16.1: Restoring the Union
The end of the Civil War saw the beginning of the Reconstruction era, when former rebel Southern states were integrated back into the Union. President Lincoln moved quickly to achieve the war’s ultimate goal: reunification of the country. He proposed a generous and non-punitive plan to return the former Confederate states speedily to the United States, but some Republicans in Congress protested, considering the president’s plan too lenient to the rebel states that had torn the country apart. The greatest flaw of Lincoln’s plan, according to this view, was that it appeared to forgive traitors instead of guaranteeing civil rights to former slaves. President Lincoln oversaw the passage of the Thirteenth Amendment abolishing slavery, but he did not live to see its ratification.
THE PRESIDENT’S PLAN
From the outset of the rebellion in 1861, Lincoln’s overriding goal had been to bring the Southern states quickly back into the fold in order to restore the Union (Figure 16.1.2). In early December 1863, the president began the process of reunification by unveiling a three-part proposal known as the ten percent planthat outlined how the states would return. The ten percent plan gave a general pardon to all Southerners except high-ranking Confederate government and military leaders; required 10 percent of the 1860 voting population in the former rebel states to take a binding oath of future allegiance to the United States and the emancipation of slaves; and declared that once those voters took those oaths, the restored Confederate states would draft new state constitutions.
Lincoln hoped that the leniency of the plan—90 percent of the 1860 voters did not have to swear allegiance to the Union or to emancipation—would bring about a quick and long-anticipated resolution and make emancipation more acceptable everywhere. This approach appealed to some in the moderate wing of the Republican Party, which wanted to put the nation on a speedy course toward reconciliation. However, the proposal instantly drew fire from a larger faction of Republicans in Congress who did not want to deal moderately with the South. These members of Congress, known as Radical Republicans, wanted to remake the South and punish the rebels. Radical Republicans insisted on harsh terms for the defeated Confederacy and protection for former slaves, going far beyond what the president proposed.
In February 1864, two of the Radical Republicans, Ohio senator Benjamin Wade and Maryland representative Henry Winter Davis, answered Lincoln with a proposal of their own. Among other stipulations, the Wade-Davis Bill called for a majority of voters and government officials in Confederate states to take an oath, called the Ironclad Oath, swearing that they had never supported the Confederacy or made war against the United States. Those who could not or would not take the oath would be unable to take part in the future political life of the South. Congress assented to the Wade-Davis Bill, and it went to Lincoln for his signature. The president refused to sign, using the pocket veto (that is, taking no action) to kill the bill. Lincoln understood that no Southern state would have met the criteria of the Wade-Davis Bill, and its passage would simply have delayed the reconstruction of the South.
THE THIRTEENTH AMENDMENT
Despite the 1863 Emancipation Proclamation, the legal status of slaves and the institution of slavery remained unresolved. To deal with the remaining uncertainties, the Republican Party made the abolition of slavery a top priority by including the issue in its 1864 party platform. The platform read: “That as slavery was the cause, and now constitutes the strength of this Rebellion, and as it must be, always and everywhere, hostile to the principles of Republican Government, justice and the National safety demand its utter and complete extirpation from the soil of the Republic; and that, while we uphold and maintain the acts and proclamations by which the Government, in its own defense, has aimed a deathblow at this gigantic evil, we are in favor, furthermore, of such an amendment to the Constitution, to be made by the people in conformity with its provisions, as shall terminate and forever prohibit the existence of Slavery within the limits of the jurisdiction of the United States.” The platform left no doubt about the intention to abolish slavery.
The president, along with the Radical Republicans, made good on this campaign promise in 1864 and 1865. A proposed constitutional amendment passed the Senate in April 1864, and the House of Representatives concurred in January 1865. The amendment then made its way to the states, where it swiftly gained the necessary support, including in the South. In December 1865, the Thirteenth Amendment was officially ratified and added to the Constitution. The first amendment added to the Constitution since 1804, it overturned a centuries-old practice by permanently abolishing slavery.
Explore a comprehensive collection of documents, images, and ephemera related toAbraham Lincoln on the Library of Congress website.
President Lincoln never saw the final ratification of the Thirteenth Amendment. On April 14, 1865, the Confederate supporter and well-known actor John Wilkes Booth shot Lincoln while he was attending a play, Our American Cousin , at Ford’s Theater in Washington. The president died the next day (Figure 16.1.3). Booth had steadfastly defended the Confederacy and white supremacy, and his act was part of a larger conspiracy to eliminate the heads of the Union government and keep the Confederate fight going. One of Booth’s associates stabbed and wounded Secretary of State William Seward the night of the assassination. Another associate abandoned the planned assassination of Vice President Andrew Johnson at the last moment. Although Booth initially escaped capture, Union troops shot and killed him on April 26, 1865, in a Maryland barn. Eight other conspirators were convicted by a military tribunal for participating in the conspiracy, and four were hanged. Lincoln’s death earned him immediate martyrdom, and hysteria spread throughout the North. To many Northerners, the assassination suggested an even greater conspiracy than what was revealed, masterminded by the unrepentant leaders of the defeated Confederacy. Militant Republicans would use and exploit this fear relentlessly in the ensuing months.
ANDREW JOHNSON AND THE BATTLE OVER RECONSTRUCTION
Lincoln’s assassination elevated Vice President Andrew Johnson, a Democrat, to the presidency. Johnson had come from very humble origins. Born into extreme poverty in North Carolina and having never attended school, Johnson was the picture of a self-made man. His wife had taught him how to read and he had worked as a tailor, a trade he had been apprenticed to as a child. In Tennessee, where he had moved as a young man, he gradually rose up the political ladder, earning a reputation for being a skillful stump speaker and a staunch defender of poor southerners. He was elected to serve in the House of Representatives in the 1840s, became governor of Tennessee the following decade, and then was elected a U.S. senator just a few years before the country descended into war. When Tennessee seceded, Johnson remained loyal to the Union and stayed in the Senate. As Union troops marched on his home state of North Carolina, Lincoln appointed him governor of the then-occupied state of Tennessee, where he served until being nominated by the Republicans to run for vice president on a Lincoln ticket. The nomination of Johnson, a Democrat and a slaveholding southerner, was a pragmatic decision made by concerned Republicans. It was important for them to show that the party supported all loyal men, regardless of their origin or political persuasion. Johnson appeared an ideal choice, because his nomination would bring with it the support of both pro-Southern elements and the War Democrats who rejected the conciliatory stance of the Copperheads, the northern Democrats who opposed the Civil War.
Unexpectedly elevated to the presidency in 1865, this formerly impoverished tailor’s apprentice and unwavering antagonist of the wealthy southern planter class now found himself tasked with administering the restoration of a destroyed South. Lincoln’s position as president had been that the secession of the Southern states was never legal; that is, they had not succeeded in leaving the Union, therefore they still had certain rights to self-government as states. In keeping with Lincoln’s plan, Johnson desired to quickly reincorporate the South back into the Union on lenient terms and heal the wounds of the nation. This position angered many in his own party. The northern Radical Republican plan for Reconstruction looked to overturn southern society and specifically aimed at ending the plantation system. President Johnson quickly disappointed Radical Republicans when he rejected their idea that the federal government could provide voting rights for freed slaves. The initial disagreements between the president and the Radical Republicans over how best to deal with the defeated South set the stage for further conflict.
In fact, President Johnson’s Proclamation of Amnesty and Reconstruction in May 1865 provided sweeping “amnesty and pardon” to rebellious Southerners. It returned to them their property, with the notable exception of their former slaves, and it asked only that they affirm their support for the Constitution of the United States. Those Southerners excepted from this amnesty included the Confederate political leadership, high-ranking military officers, and persons with taxable property worth more than $20,000. The inclusion of this last category was specifically designed to make it clear to the southern planter class that they had a unique responsibility for the outbreak of hostilities. But it also satisfied Johnson’s desire to exact vengeance on a class of people he had fought politically for much of his life. For this class of wealthy Southerners to regain their rights, they would have to swallow their pride and request a personal pardon from Johnson himself.
For the Southern states, the requirements for readmission to the Union were also fairly straightforward. States were required to hold individual state conventions where they would repeal the ordinances of secession and ratify the Thirteenth Amendment. By the end of 1865, a number of former Confederate leaders were in the Union capital looking to claim their seats in Congress. Among them was Alexander Stephens, the vice president of the Confederacy, who had spent several months in a Boston jail after the war. Despite the outcries of Republicans in Congress, by early 1866 Johnson announced that all former Confederate states had satisfied the necessary requirements. According to him, nothing more needed to be done; the Union had been restored.
Understandably, Radical Republicans in Congress did not agree with Johnson’s position. They, and their northern constituents, greatly resented his lenient treatment of the former Confederate states, and especially the return of former Confederate leaders like Alexander Stephens to Congress. They refused to acknowledge the southern state governments he allowed. As a result, they would not permit senators and representatives from the former Confederate states to take their places in Congress.
Instead, the Radical Republicans created a joint committee of representatives and senators to oversee Reconstruction. In the 1866 congressional elections, they gained control of the House, and in the ensuing years they pushed for the dismantling of the old southern order and the complete reconstruction of the South. This effort put them squarely at odds with President Johnson, who remained unwilling to compromise with Congress, setting the stage for a series of clashes.
Section Summary
President Lincoln worked to reach his goal of reunifying the nation quickly and proposed a lenient plan to reintegrate the Confederate states. After his murder in 1865, Lincoln’s vice president, Andrew Johnson, sought to reconstitute the Union quickly, pardoning Southerners en masse and providing Southern states with a clear path back to readmission. By 1866, Johnson announced the end of Reconstruction. Radical Republicans in Congress disagreed, however, and in the years ahead would put forth their own plan of Reconstruction.
Review Questions
What was Lincoln’s primary goal immediately following the Civil War?
- punishing the rebel states
- improving the lives of former slaves
- reunifying the country
- paying off the debts of the war
C
In 1864 and 1865, Radical Republicans were most concerned with ________.
- securing civil rights for freed slaves
- barring ex-Confederates from political office
- seeking restitution from Confederate states
- preventing Andrew Johnson’s ascent to the presidency
B
What was the purpose of the Thirteenth Amendment? How was it different from the Emancipation Proclamation?
The Thirteenth Amendment officially and permanently banned the institution of slavery in the United States. The Emancipation Proclamation had freed only those slaves in rebellious states, leaving many slaves—most notably, those in the border states—in bondage; furthermore, it did not alter or prohibit the institution of slavery in general.
Glossary
- Ironclad Oath
- an oath that the Wade-Davis Bill required a majority of voters and government officials in Confederate states to take; it involved swearing that they had never supported the Confederacy
- Radical Republicans
- northern Republicans who contested Lincoln’s treatment of Confederate states and proposed harsher punishments
- Reconstruction
- the twelve-year period after the Civil War in which the rebel Southern states were integrated back into the Union
- ten percent plan
- Lincoln’s Reconstruction plan, which required only 10 percent of the 1860 voters in Confederate states to take an oath of allegiance to the Union


12.2: Support and Protection of the Brain
By the end of this section, you will be able to:
- Describe the meninges that protect the brain
- Describe the blood vessels that supply the brain
- Name the components of the ventricular system and the regions of the brain in which each is located
- Explain the production of cerebrospinal fluid and its flow through the ventricles
Protective Coverings of the Brain
The central nervous system (CNS) is crucial to the operation of the body and any compromise of function in the brain and spinal cord can lead to severe difficulties. The brain is protected by multiple structures. First, the bones of the skull enclose and house the brain. Underneath the skeletal structures, the brain is protected by membranes made by connective tissue, called meninges , that surround, support, stabilize and partition the nervous tissue (Figure \(\PageIndex{1}\)). In addition, the brain has a privileged blood supply, as suggested by the blood-brain barrier. The function of the tissue is crucial to the survival of the organism, so the contents of the blood cannot simply pass into the central nervous tissue. To protect this region from the toxins and pathogens that may be traveling through the blood stream, there is strict control over what can move out of the general systems and into the brain. Because of this privilege, the brain needs specialized structures for the maintenance of circulation. This begins with a unique arrangement of blood vessels carrying fresh blood into the brain and venous sinuses carrying deoxygenated blood out of the brain. Beyond the supply of blood, the brain filters the blood into cerebrospinal fluid (CSF), which is then circulated through the cavities of the brain, such as the subarachnoid space and the ventricles.
Cranial Meninges
The outer surface of the CNS is covered by a series of membranes composed of connective tissue called the meninges, which protect, stabilize and partition the brain. From superficial to deep, the meningeal layers are the dura mater, arachnoid mater and pia mater.  It is anchored to the inner surface of the cranium and vertebral cavity. The arachnoid mater is a membrane of thin fibrous tissue that forms a loose sac around the brain. Beneath the arachnoid mater, there is a space called the subarachnoid space where a thin, filamentous mesh form the arachnoid trabeculae , that looking like a spider web give this layer its name. Directly adjacent to the surface of the brain is the pia mater , a thin fibrous membrane that follows the superficial convolutions of the brain and fits into other grooves and indentations (Figure \(\PageIndex{2}\)).
Dura Mater
Like a thick cap covering the brain, the dura mater is a tough outer covering. The name comes from the Latin for “tough mother” to represent its physically protective role. It encloses the entire CNS and the major blood vessels that enter the cranium and vertebral cavity. It is directly attached to the inner surface of the bones of the cranium and to the very end of the vertebral cavity. The dura mater of the brain is made by two layers, the periosteal layer which is more superficial and attached to the skull, and the meningeal layer , which lies deep to the first layer. These two layers are usually fused together. However, in some regions of the brain they separate to form large space filled with venous blood called dural sinuses . The dura mater of the spinal cord is composed of only one layer. The region between the bones and the dura mater is called epidural space . In the cranium, the epidural space contains arteries and veins that supply and drain blood from the brain. In normal conditions, the cranial epidural space is a potential space and not a real space. However, trauma can cause the leakage of fluid (hematomas) which accumulates in the epidural space enlarging it and transforming it into a real space. In the vertebral column, the epidural space is a real space that contains areolar and adipose connective tissue for an extra layer of protection, as well as blood vessels. The spinal epidural space at the lumbar level is where epidural injections are administered. Deep to the dura mater, there is another potential space called the subdural space . As the epidural space, this space can be filled with fluid causing a subdural hematoma.
The meningeal layer of the dura mater extends into the cranial cavity at four locations. These flat partitions are called cranial dural septa and separate specific parts of the brain (Figure \(\PageIndex{3}\)). The falx cerebri goes through the midline separation of the brain while the falx cerebelli separates the two cerebellar hemispheres. The tentorium cerebelli separates the cerebellum from the superior part of the brain (cerebrum), forming a shelf-like tent. Another partition called diaphragma sellae surrounds the pituitary gland.
Arachnoid Mater
Deep to the subdural space lies the middle layer of the meninges called the arachnoid mater. This layer is named for the spider-web–like projections called arachnoid trabeculae between this layer and the pia mater. The arachnoid defines a sac-like enclosure around the CNS. The trabeculae are found in the subarachnoid space , which is filled with circulating CSF, making it a real space. The arachnoid emerges into the dural sinuses as the arachnoid granulations , where the CSF is filtered back into the blood for drainage from the nervous system.
Pia Mater
The outer surface of the CNS is covered in the thin fibrous membrane of the pia mater. It is thought to have a continuous layer of cells providing a fluid-impermeable membrane. The name pia mater comes from the Latin for “tender mother,” suggesting the thin membrane is a gentle covering for the brain. The pia extends into every convolution of the CNS. Blood vessels that are nourishing the central nervous tissue are between the pia mater and the nervous tissue.
DISORDERS OF THE...
Meninges: Meningitis
Meningitis is an inflammation of the meninges, the three layers of fibrous membrane that surround the CNS. Meningitis can be caused by infection by bacteria or viruses. The particular pathogens are not special to meningitis; it is just an inflammation of that specific set of tissues from what might be a broader infection. Bacterial meningitis can be caused by Streptococcus, Staphylococcus, or the tuberculosis pathogen, among many others. Viral meningitis is usually the result of common enteroviruses (such as those that cause intestinal disorders), but may be the result of the herpes virus or West Nile virus. Bacterial meningitis tends to be more severe.
The symptoms associated with meningitis can be fever, chills, nausea, vomiting, light sensitivity, soreness of the neck, or severe headache. More important are the neurological symptoms, such as changes in mental state (confusion, memory deficits, and other dementia-type symptoms). A serious risk of meningitis can be damage to peripheral structures because of the nerves that pass through the meninges. Hearing loss is a common result of meningitis.
The primary test for meningitis is a lumbar puncture. A needle inserted into the lumbar region of the spinal column through the dura mater and arachnoid membrane into the subarachnoid space can be used to withdraw the fluid for chemical testing. Fatality occurs in 5 to 40 percent of children and 20 to 50 percent of adults with bacterial meningitis. Treatment of bacterial meningitis is through antibiotics, but viral meningitis cannot be treated with antibiotics because viruses do not respond to that type of drug. Fortunately, the viral forms are milder.
Blood Supply to the Brain
A lack of oxygen to the CNS can be devastating, and the cardiovascular system has specific regulatory reflexes to ensure that the blood supply is not interrupted. There are multiple routes for blood to get into the CNS, with specializations to protect that blood supply and to maximize the ability of the nervous tissue to get an uninterrupted perfusion.
Arterial Supply to the Brain
The major artery carrying recently oxygenated blood away from the heart is the aorta. The very first branches off the aorta supply the heart with nutrients and oxygen. The next branches give rise to the common carotid arteries , which further branch into the internal carotid arteries . The external carotid arteries supply blood to the tissues on the surface of the cranium. The internal carotid artery enters the cranium through the carotid canal in the temporal bone.
A second set of vessels that supply the CNS are the vertebral arteries , which are protected as they pass through the neck region by the transverse foramina of the cervical vertebrae. The vertebral arteries enter the cranium through the foramen magnum of the occipital bone. The two vertebral arteries then merge into the basilar artery , which gives rise to branches to the brainstem and cerebellum. The left and right internal carotid arteries and branches of the basilar artery all become the circle of Willis , a confluence of arteries that can maintain perfusion of the brain even if narrowing or a blockage limits flow through one part (Figure \(\PageIndex{4}\)).
Interactive Link
Circle of Willis
Watch this animation of the Circle of Willis to see how blood flows to the brain and passes through it before being distributed through the tissues. The circle of Willis is a specialized arrangement of arteries that ensure constant perfusion of the brain even in the event of a blockage of one of the arteries in the circle. The animation shows the normal direction of flow through the circle of Willis to the middle cerebral artery. Where would the blood come from if there were a blockage just posterior to the middle cerebral artery on the left?
- Answer
-
If blood could not get to the middle cerebral artery through the posterior circulation, the blood would flow around the circle of Willis to reach that artery from an anterior vessel. Blood flow would just reverse within the circle.
Venous Return from the Brain
After passing through the CNS, blood returns to the circulation through a series of dural sinuses and cerebral veins (Figure \(\PageIndex{5}\)). The dural sinuses are housed within the two layers of the dura mater. The superior sagittal sinus runs in the medial groove of the brain, where it absorbs CSF from the meninges. The superior sagittal sinus drains to the confluence of sinuses , along with the occipital sinuses and straight sinus , to then drain into the transverse sinuses . The transverse sinuses connect to the sigmoid sinuses , which then connect to the jugular veins . From there, the blood continues toward the heart to be pumped to the lungs for reoxygenation.
Ventricular System
Cerebrospinal fluid (CSF) is produced by a type of specialized membrane made of ependymal cells called a choroid plexus . Ependymal cells (one of the types of glial cells described in the introduction to the nervous system) surround blood capillaries and filter the blood to make CSF. The fluid is a clear solution with a limited amount of the constituents of blood. It is essentially water, small molecules, and electrolytes and is continuous with the interstitial fluid. Oxygen and carbon dioxide are dissolved into the CSF, as they are in blood, and can diffuse between the fluid and the nervous tissue. CSF circulates through the nervous tissue to remove metabolic wastes from the interstitial fluids of nervous tissues and return them to the blood stream. The choroid plexus lines open spaces within the brain called ventricles . The CSF circulates through all of the ventricles to eventually emerge into the subarachnoid space where it will be reabsorbed into the blood.
Ventricles
There are four ventricles within the brain, all of which developed from the original hollow space within the neural tube, the central canal . The first two are named the lateral ventricles and are deep within the brain (Figure \(\PageIndex{6}\)). The two lateral ventricles are shaped as a C and are located in the left and right hemispheres, and were at one time referred to as the first and second ventricles. These ventricles are connected to the third ventricle by two openings called the interventricular foramina . The third ventricle opens into a canal called the cerebral aqueduct that passes through the midbrain and connects the third ventricle to the fourth ventricle . The fourth ventricle is the space between the cerebellum and the pons and upper medulla. The ventricular system opens up to the subarachnoid space from the fourth ventricle. The single median aperture and the pair of lateral apertures connect to the subarachnoid space so that CSF can flow through the ventricles and around the outside of the CNS (Figure \(\PageIndex{7}\)). From the fourth ventricle, CSF can continue down the central canal of the spinal cord.
Cerebrospinal Fluid Circulation
The choroid plexuses are found in all four ventricles. Observed in dissection, they appear as soft, fuzzy structures that may still be pink, depending on how well the circulatory system is cleared in preparation of the tissue. The CSF is produced from components extracted from the blood, so its flow out of the ventricles is tied to the pulse of cardiovascular circulation.
From the lateral ventricles, the CSF flows into the third ventricle, where more CSF is produced, and then through the cerebral aqueduct into the fourth ventricle where even more CSF is produced (Figure \(\PageIndex{7}\)). A very small amount of CSF is filtered at any one of the plexuses, for a total of about 500 milliliters daily, but it is continuously made and pulses through the ventricular system, keeping the fluid moving. From the fourth ventricle, CSF can continue down the central canal of the spinal cord, but this is essentially a cul-de-sac, so more of the fluid leaves the ventricular system and moves into the subarachnoid space through the median and lateral apertures.
Within the subarachnoid space, the CSF flows around all of the CNS, providing two important functions. As with elsewhere in its circulation, the CSF picks up metabolic wastes from the nervous tissue and moves it out of the CNS. It also acts as a liquid cushion for the brain and spinal cord. By surrounding the entire system in the subarachnoid space, it provides a thin buffer around the organs within the strong, protective dura mater. The arachnoid granulations are outpocketings of the arachnoid membrane into the dural sinuses so that CSF can be reabsorbed into the blood, along with the metabolic wastes. From the dural sinuses, blood drains out of the head and neck through the jugular veins, along with the rest of the circulation for blood, to be reoxygenated by the lungs and wastes to be filtered out by the kidneys.
DISORDERS OF THE...
Central Nervous System: Strokes
The supply of blood to the brain is crucial to its ability to perform many functions. Without a steady supply of oxygen, and to a lesser extent glucose, the nervous tissue in the brain cannot keep up its extensive electrical activity. These nutrients get into the brain through the blood, and if blood flow is interrupted, neurological function is compromised.
The common name for a disruption of blood supply to the brain is a stroke. It is caused by a blockage to an artery in the brain or by blood leaking out of blood vessels (hemorrhagic stroke), although less common.  When the blood cannot travel through the artery, the surrounding tissue that is deprived starves and dies. Strokes will often result in the loss of very specific functions. A stroke in the lateral medulla, for example, can cause a loss in the ability to swallow. Sometimes, seemingly unrelated functions will be lost because they are dependent on structures in the same region. Along with the swallowing in the previous example, a stroke in that region could affect sensory functions from the face or extremities because important white matter pathways also pass through the lateral medulla. Loss of blood flow to specific regions of the brain can lead to the loss of specific higher functions, from the ability to recognize faces to the ability to move a particular region of the body. Severe or limited memory loss can be the result of a temporal lobe stroke.
Related to strokes are transient ischemic attacks (TIAs), which can also be called “mini-strokes.” These are events in which a physical blockage may be temporary, cutting off the blood supply and oxygen to a region, but not to the extent that it causes cell death in that region. While the neurons in that area are recovering from the event, neurological function may be lost. TIAs usually resolve spontaneously by the body, that is why it is called "transient".
Recovery from a stroke (or TIA) is strongly dependent on the speed of treatment. Often, the person who is present and notices something is wrong must then make a decision. The mnemonic FAST helps people remember what to look for when someone is dealing with sudden losses of neurological function. If someone complains of feeling “funny,” check these things quickly: Look at the person’s face. Does he or she have problems moving Face muscles and making regular facial expressions? Ask the person to raise his or her Arms above the head. Can the person lift one arm but not the other? Has the person’s Speech changed? Is he or she slurring words or having trouble saying things? If any of these things have happened, then it is Time to call for help.
Sometimes, treatment with blood-thinning drugs can alleviate the problem, and recovery is possible. If the tissue is damaged, the amazing thing about the nervous system is that it is adaptable. With physical, occupational, and speech therapy, victims of strokes can recover, or more accurately relearn, functions.
Concept Review
The CNS has a privileged blood supply established by the blood-brain barrier. Establishing this barrier are anatomical structures that help to protect and isolate the CNS. The skull and vertebral column are the first mean of protection of the brain and spinal cord, respectively. Layers of connective tissue called meninges support and stabilize the brain and spinal cord, as well as partition the brain into specific regions. The outer layer is the dura mater, the middle layer is the arachnoid mater and the inner layer is the pia mater.
The arterial blood to the brain comes from the internal carotid and vertebral arteries, which both contribute to the unique circle of Willis that provides constant perfusion of the brain even if one of the blood vessels is blocked or narrowed. That blood is eventually filtered to make a separate medium, the CSF, that circulates within the spaces of the brain and then into the surrounding space defined by the meninges, the protective covering of the brain and spinal cord.
The blood that nourishes the brain and spinal cord is behind the glial-cell–enforced blood-brain barrier, which limits the exchange of material from blood vessels with the interstitial fluid of the nervous tissue. Thus, metabolic wastes are collected in cerebrospinal fluid that circulates through the CNS. This fluid is produced by filtering blood at the choroid plexuses in the four ventricles of the brain. It then circulates through the ventricles and into the subarachnoid space, between the pia mater and the arachnoid mater. From the arachnoid granulations, CSF is reabsorbed into the blood, removing the waste from the privileged central nervous tissue.
The blood, now with the reabsorbed CSF, drains out of the cranium through the dural sinuses. The dura mater is the tough outer covering of the CNS, which is anchored to the inner surface of the cranial and vertebral cavities. It surrounds the venous space known as the dural sinuses, which connect to the jugular veins, where blood drains from the head and neck.
Review Questions
Q. What blood vessel enters the cranium to supply the brain with fresh, oxygenated blood?
A. common carotid artery
B. jugular vein
C. internal carotid artery
D. aorta
- Answer
-
C
Q. Which layer of the meninges surrounds and supports the sinuses that form the route through which blood drains from the CNS?
A. dura mater
B. arachnoid mater
C. subarachnoid
D. pia mater
- Answer
-
A
Q. What type of glial cell is responsible for filtering blood to produce CSF at the choroid plexus?
A. ependymal cell
B. astrocyte
C. oligodendrocyte
D. Schwann cell
- Answer
-
A
Critical Thinking Questions
Q. Why can the circle of Willis maintain perfusion of the brain even if there is a blockage in one part of the structure?
A. The structure is a circular connection of blood vessels, so that blood coming up from one of the arteries can flow in either direction around the circle and avoid any blockage or narrowing of the blood vessels.
Q. Meningitis is an inflammation of the meninges that can have severe effects on neurological function. Why is infection of this structure potentially so dangerous?
A. The nerves that connect the periphery to the CNS pass through these layers of tissue and can be damaged by that inflammation, causing a loss of important neurological functions.
Glossary
- arachnoid granulation
- outpocket of the arachnoid membrane into the dural sinuses that allows for reabsorption of CSF into the blood
- arachnoid mater
- middle layer of the meninges named for the spider-web–like trabeculae that extend between it and the pia mater
- arachnoid trabeculae
- filaments between the arachnoid and pia mater within the subarachnoid space
- basilar artery
- blood vessel from the merged vertebral arteries that runs along the dorsal surface of the brainstem
- central canal
- hollow space within the spinal cord that is the remnant of the center of the neural tube
- cerebral aqueduct
- connection of the ventricular system between the third and fourth ventricles located in the midbrain
- choroid plexus
- specialized structures containing ependymal cells lining blood capillaries that filter blood to produce CSF in the four ventricles of the brain
- circle of Willis
- unique anatomical arrangement of blood vessels around the base of the brain that maintains perfusion of blood into the brain even if one component of the structure is blocked or narrowed
- common carotid artery
- blood vessel that branches off the aorta (or the brachiocephalic artery on the right) and supplies blood to the head and neck
- confluence of sinuses
- connecting point of the superior sagittal sinus, straight sinus, and occipital sinus
- cranial dura septa
- extensions of meningeal dura mater into the cranial cavity
- diaphragma sellae
- extension of the dura that separates the pituitary from the neural structures located superiorly including the optic chiasm
- dura mater
- tough, fibrous, outer layer of the meninges that is attached to the inner surface of the cranium and vertebral column and surrounds the entire CNS
- dural sinus
- any of the venous structures surrounding the brain, enclosed within the dura mater, which drain blood from the CNS to the common venous return of the jugular veins
- epidural space
- area between the dura mater and the above structures
- falx cerebelli
- extension of dura mater, projecting to the cerebellum
- falx cerebri
- extension of dura mater that lies between the cerebral hemispheres, in the longitudinal fissure
- fourth ventricle
- the portion of the ventricular system that is in the region of the brainstem and opens into the subarachnoid space through the median and lateral apertures
- internal carotid artery
- branch from the common carotid artery that enters the cranium and supplies blood to the brain
- interventricular foramina
- openings between the lateral ventricles and third ventricle allowing for the passage of CSF
- jugular veins
- blood vessels that return “used” blood from the head and neck
- lateral apertures
- pair of openings from the fourth ventricle to the subarachnoid space on either side and between the medulla and cerebellum
- lateral ventricles
- portions of the ventricular system that are deep within the brain
- median aperture
- singular opening from the fourth ventricle into the subarachnoid space at the midline between the medulla and cerebellum
- meningeal layer
- one of the two layers of the cranial dura mater
- meninges
- protective outer coverings of the CNS composed of connective tissue
- occipital sinuses
- dural sinuses along the edge of the most posterior region of the brain
- periosteal layer
- one of the two layers of the cranial dura mater
- pia mater
- thin, innermost membrane of the meninges that directly covers the surface of the CNS
- sigmoid sinuses
- dural sinuses that drain directly into the jugular veins
- straight sinus
- dural sinus that drains blood from the deep center of the brain to collect with the other sinuses
- subarachnoid space
- space between the arachnoid mater and pia mater that contains CSF and the fibrous connections of the arachnoid trabeculae
- subdural space
- space between the dura mater and arachnoid mater
- superior sagittal sinus
- dural sinus that runs along the top of the longitudinal fissure and drains blood from the majority of the outer brain
- tentorium cerebelli
- extension of dura mater that covers the upper surface of the cerebellum
- third ventricle
- portion of the ventricular system that is in the region of the diencephalon
- transverse sinuses
- dural sinuses that drain along either side of the occipital–cerebellar space
- ventricles
- remnants of the hollow center of the neural tube that are spaces for cerebrospinal fluid to circulate through the brain
- vertebral arteries
- arteries that ascend along either side of the vertebral column through the transverse foramina of the cervical vertebrae and enter the cranium through the foramen magnum
-
Contributors and Attributions
-
OpenStax Anatomy & Physiology (CC BY 4.0). Access for free at https://openstax.org/books/anatomy-and-physiology


5.2: The Ethical and Legal Implications of Information Systems
The rapid changes in information technology in the past few decades have brought a broad array of new capabilities and powers to governments, organizations, and individuals alike. These new capabilities have required thoughtful analysis and the creation of new norms, regulations, and laws. In this chapter, we have seen how the areas of intellectual property and privacy have been affected by these new capabilities and how the regulatory environment has been changed to address them.
Information Systems Ethics
The term ethics is defined as “a set of moral principles” or “the principles of conduct governing an individual or a group.” Since the dawn of civilization, the study of ethics and its impact has fascinated mankind. But what do ethics have to do with information systems?
The introduction of new technology can have a profound effect on human behavior. New technologies give us capabilities that we did not have before, which in turn create environments and situations that have not been specifically addressed in ethical terms. Those who master new technologies gain new power; those who cannot or do not master them may lose power. In 1913, Henry Ford implemented the first moving assembly line to create his Model T cars. While this was a great step forward technologically (and economically), the assembly line reduced the value of human beings in the production process. The development of the atomic bomb concentrated unimaginable power in the hands of one government, which then had to wrestle with the decision to use it. Today’s digital technologies have created new categories of ethical dilemmas.
For example, the ability to anonymously make perfect copies of digital music has tempted many music fans to download copyrighted music for their own use without making payment to the music’s owner. Many of those who would never have walked into a music store and stolen a CD find themselves with dozens of illegally downloaded albums.
Digital technologies have given us the ability to aggregate information from multiple sources to create profiles of people. What would have taken weeks of work in the past can now be done in seconds, allowing private organizations and governments to know more about individuals than at any time in history. This information has value but also chips away at the privacy of consumers and citizens.
Code of Ethics
One method for navigating new ethical waters is a code of ethics. A code of ethics is a document that outlines a set of acceptable behaviors for a professional or social group; generally, it is agreed to by all members of the group. The document details different actions that are considered appropriate and inappropriate.
A good example of a code of ethics is the Code of Ethics and Professional Conduct of the Association for Computing Machinery, an organization of computing professionals that includes academics, researchers, and practitioners. Here is a quote from the preamble:
Commitment to ethical professional conduct is expected of every member (voting members, associate members, and student members) of the Association for Computing Machinery (ACM).
This Code, consisting of 24 imperatives formulated as statements of personal responsibility, identifies the elements of such a commitment. It contains many, but not all, issues professionals are likely to face. Section 1 outlines fundamental ethical considerations, while Section 2 addresses additional, more specific considerations of professional conduct. Statements in Section 3 pertain more specifically to individuals who have a leadership role, whether in the workplace or in a volunteer capacity such as with organizations like ACM. Principles involving compliance with this Code are given in Section 4 .
In the ACM’s code, you will find many straightforward ethical instructions, such as the admonition to be honest and trustworthy. But because this is also an organization of professionals that focuses on computing, there are more specific admonitions that relate directly to information technology:
- No one should enter or use another’s computer system, software, or data files without permission. One must always have appropriate approval before using system resources, including communication ports, file space, other system peripherals, and computer time.
- Designing or implementing systems that deliberately or inadvertently demean individuals or groups is ethically unacceptable.
- Organizational leaders are responsible for ensuring that computer systems enhance, not degrade, the quality of working life. When implementing a computer system, organizations must consider the personal and professional development, physical safety, and human dignity of all workers. Appropriate human-computer ergonomic standards should be considered in system design and in the workplace.
One of the major advantages of creating a code of ethics is that it clarifies the acceptable standards of behavior for a professional group. The varied backgrounds and experiences of the members of a group lead to a variety of ideas regarding what is acceptable behavior. While to many the guidelines may seem obvious, having these items detailed provides clarity and consistency. Explicitly stating standards communicates the common guidelines to everyone in a clear manner.
Having a code of ethics can also have some drawbacks. First of all, a code of ethics does not have legal authority; in other words, breaking a code of ethics is not a crime in itself. So what happens if someone violates one of the guidelines? Many codes of ethics include a section that describes how such situations will be handled. In many cases, repeated violations of the code result in expulsion from the group.
In the case of ACM: “Adherence of professionals to a code of ethics is largely a voluntary matter. However, if a member does not follow this code by engaging in gross misconduct, membership in ACM may be terminated.” Expulsion from ACM may not have much of an impact on many individuals, since membership in ACM is usually not a requirement for employment. However, expulsion from other organizations, such as a state bar organization or medical board, could carry a huge impact.
Another possible disadvantage of a code of ethics is that there is always a chance that important issues will arise that are not specifically addressed in the code. Technology is quickly changing, and a code of ethics might not be updated often enough to keep up with all of the changes. A good code of ethics, however, is written in a broad enough fashion that it can address the ethical issues of potential changes to technology while the organization behind the code makes revisions.
Finally, a code of ethics could have also been a disadvantage in that it may not entirely reflect the ethics or morals of every member of the group. Organizations with a diverse membership may have internal conflicts as to what is acceptable behavior. For example, there may be a difference of opinion on the consumption of alcoholic beverages at company events. In such cases, the organization must make a choice about the importance of addressing a specific behavior in the code.
Acceptable Use Policy
Many organizations that provide technology services to a group of constituents or the public require agreement to an acceptable use policy (AUP) before those services can be accessed. Similar to a code of ethics, this policy outlines what is allowed and what is not allowed while someone is using the organization’s services. An everyday example of this is the terms of service that must be agreed to before using the public Wi-Fi at Starbucks, McDonald’s, or even a university. Here is an example of an acceptable use policy from Virginia Tech .
Just as with a code of ethics, these acceptable use policies specify what is allowed and what is not allowed. Again, while some of the items listed are obvious to most, others are not so obvious:
- “Borrowing” someone else’s login ID and password is prohibited.
- Using the provided access for commercial purposes, such as hosting your own business website, is not allowed.
- Sending out unsolicited emails to a large group of people is prohibited.
Also as with codes of ethics, violations of these policies have various consequences. In most cases, such as with Wi-Fi, violating the acceptable use policy will mean that you will lose your access to the resource. While losing access to Wi-Fi at Starbucks may not have a lasting impact, a university student getting banned from the university’s Wi-Fi (or possibly all network resources) could have a large impact.
Intellectual Property
One of the domains that have been deeply impacted by digital technologies is the domain of intellectual property. Digital technologies have driven a rise in new intellectual property claims and made it much more difficult to defend intellectual property.
Intellectual property is defined as “property (as an idea, invention, or process) that derives from the work of the mind or intellect.” [3] This could include creations such as song lyrics, a computer program, a new type of toaster, or even a sculpture.
Practically speaking, it is very difficult to protect an idea. Instead, intellectual property laws are written to protect the tangible results of an idea. In other words, just coming up with a song in your head is not protected, but if you write it down it can be protected.
Protection of intellectual property is important because it gives people an incentive to be creative. Innovators with great ideas will be more likely to pursue those ideas if they have a clear understanding of how they will benefit. In the US Constitution, Article 8, Section 8, the authors saw fit to recognize the importance of protecting creative works:
Congress shall have the power . . . To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.
An important point to note here is the “limited time” qualification. While protecting intellectual property is important because of the incentives it provides, it is also necessary to limit the amount of benefit that can be received and allow the results of ideas to become part of the public domain.
Outside of the US, intellectual property protections vary. You can find out more about a specific country’s intellectual property laws by visiting the World Intellectual Property Organization .
Copyright
Copyright is the protection given to songs, computer programs, books, and other creative works; any work that has an “author” can be copyrighted. Under the terms of copyright, the author of work controls what can be done with the work, including:
- Who can make copies of the work.
- Who can make derivative works from the original work.
- Who can perform the work publicly.
- Who can display the work publicly.
- Who can distribute the work.
Many times, work is not owned by an individual but is instead owned by a publisher with whom the original author has an agreement. In return for the rights to the work, the publisher will market and distribute the work and then pay the original author a portion of the proceeds.
Copyright protection lasts for the life of the original author plus seventy years. In the case of a copyrighted work owned by a publisher or another third party, the protection lasts for ninety-five years from the original creation date. For works created before 1978, the protections vary slightly. You can see the full details on copyright protections by reviewing the Copyright Basics document available at the US Copyright Office’s website .
Obtaining Copyright Protection
In the United States, copyright is obtained by the simple act of creating the original work. In other words, when an author writes down that song, makes that film, or designs that program, he or she automatically has the copyright. However, for a work that will be used commercially, it is advisable to register for a copyright with the US Copyright Office. A registered copyright is needed in order to bring legal action against someone who has used a work without permission.
First Sale Doctrine
If an artist creates a painting and sells it to a collector who then, for whatever reason, proceeds to destroy it, does the original artist have any recourse? What if the collector, instead of destroying it, begins making copies of it and sells them? Is this allowed? The first sale doctrine is a part of copyright law that addresses this, as shown below [4] :
The first sale doctrine, codified at 17 U.S.C. § 109, provides that an individual who knowingly purchases a copy of a copyrighted work from the copyright holder receives the right to sell, display or otherwise dispose of that particular copy , notwithstanding the interests of the copyright owner.
So, in our examples, the copyright owner has no recourse if the collector destroys her artwork. But the collector does not have the right to make copies of the artwork.
Fair Use
Another important provision within copyright law is that of fair use. Fair use is a limitation on copyright law that allows for the use of protected works without prior authorization in specific cases. For example, if a teacher wanted to discuss a current event in her class, she could pass out copies of a copyrighted news story to her students without first getting permission. Fair use is also what allows a student to quote a small portion of a copyrighted work in a research paper.
Unfortunately, the specific guidelines for what is considered fair use and what constitutes copyright violation are not well defined. Fair use is a well-known and respected concept and will only be challenged when copyright holders feel that the integrity or market value of their work is being threatened. The following four factors are considered when determining if something constitutes fair use: [5]
- The purpose and character of the use, including whether such use is of commercial nature or is for nonprofit educational purposes;
- The nature of the copyrighted work;
- The amount and substantiality of the portion used in relation to the copyrighted work as a whole;
- The effect of the use upon the potential market for, or value of, the copyrighted work.
If you are ever considering using a copyrighted work as part of something you are creating, you may be able to do so under fair use. However, it is always best to check with the copyright owner to be sure you are staying within your rights and not infringing upon theirs.
Patent
Another important form of intellectual property protection is the patent. A patent creates protection for someone who invents a new product or process. The definition of invention is quite broad and covers many different fields. Here are some examples of items receiving patents:
- circuit designs in semiconductors;
- prescription drug formulas;
- firearms;
- locks;
- plumbing;
- engines;
- coating processes; and
- business methods.
Once a patent is granted, it provides the inventor with protection from others infringing on his or her patent. A patent holder has the right to exclude others from making, using, offering for sale, or selling the invention throughout the United States or importing the invention into the United States for a limited time in exchange for public disclosure of the invention when the patent is granted.
As with copyright, patent protection lasts for a limited period of time before the invention or process enters the public domain. In the US, a patent lasts twenty years. This is why generic drugs are available to replace brand-name drugs after twenty years.
Business Method Patents
Most patents protect a physical object. However, a business method patent is a type of utility patent that protects a process such as one created in a software program. It has proved especially useful to online companies that use software for their business. Protection through a business method patent, also known as an Internet patent, allows the owner to control rights to that business method during the life of the patent. This means that they can prevent other companies from using the process, or they can license the process to other companies for a fee.
Requirements for Business Method Patents
There are four main requirements for patenting a business method. First, the business method must be patentable subject matter rather than an abstract idea. It also must meet the usefulness requirement, but this is a low threshold to meet. The method only must produce a concrete result. The two remaining requirements are more complicated. These involve showing that the method is novel and that it is not obvious.
A novel business method must be different from any previous method or invention, and it must not have been exposed to the public. A method is exposed to the public if it was used publicly or described in a publication before the application was filed. (An exception applies if the applicant described the method in a publication no more than one year before the filing date.)
A business method that is non-obvious must produce a result that is new or unexpected to someone in the relevant field. This is often determined by assessing whether someone in the field would have seen the new method as a natural evolution of previous methods.
The Digital Millennium Copyright Act
As digital technologies have changed what it means to create, copy, and distribute media, a policy vacuum has been created. In 1998, the US Congress passed the Digital Millennium Copyright Act (DMCA), which extended copyright law to take into consideration digital technologies. Two of the best-known provisions from the DMCA are the anti-circumvention provision and the “safe harbor” provision.
- The anti-circumvention provision makes it illegal to create technology to circumvent technology that has been put in place to protect a copyrighted work. This provision includes not just the creation of the technology but also the publishing of information that describes how to do it. While this provision does allow for some exceptions, it has become quite controversial and has led to a movement to have it modified.
- The “safe harbor” provision limits the liability of online service providers when someone using their services commits copyright infringement. This is the provision that allows YouTube, for example, not to be held liable when someone posts a clip from a copyrighted movie. The provision does require the online service provider to take action when they are notified of the violation (a “takedown” notice).
Many think that the DMCA goes too far and ends up limiting our freedom of speech. The Electronic Frontier Foundation (EFF) is at the forefront of this battle. For example, in discussing the anti-circumvention provision, the EFF states:
Yet the DMCA has become a serious threat that jeopardizes fair use, impedes competition and innovation, chills free expression and scientific research, and interferes with computer intrusion laws. If you circumvent DRM [digital rights management] locks for non-infringing fair uses or create the tools to do so you might be on the receiving end of a lawsuit.
Privacy
The term privacy has many definitions, but for our purposes, privacy will mean the ability to control information about oneself. Our ability to maintain our privacy has eroded substantially in the past decades, due to information systems.
Personally Identifiable Information
Information about a person that can be used to uniquely establish that person’s identify is called personally identifiable information, or PII. This is a broad category that includes information such as:
- name;
- social security number;
- date of birth;
- place of birth;
- mother‘s maiden name;
- biometric records (fingerprint, face, etc.);
- medical records;
- educational records;
- financial information; and
- employment information.
Organizations that collect PII are responsible to protect it. The Department of Commerce recommends that “organizations minimize the use, collection, and retention of PII to what is strictly necessary to accomplish their business purpose and mission.” They go on to state that “the likelihood of harm caused by a breach involving PII is greatly reduced if an organization minimizes the amount of PII it uses, collects, and stores.” [7] Organizations that do not protect PII can face penalties, lawsuits, and loss of business. In the US, most states now have laws in place requiring organizations that have had security breaches related to PII to notify potential victims, as does the European Union.
Just because companies are required to protect your information does not mean they are restricted from sharing it. In the US, companies can share your information without your explicit consent (see sidebar below), though not all do so. Companies that collect PII are urged by the FTC to create a privacy policy and post it on their website.
While the privacy laws in the US seek to balance consumer protection with promoting commerce, in the European Union privacy is considered a fundamental right that outweighs the interests of commerce. This has led to much stricter privacy protection in the EU, but also makes commerce more difficult between the US and the EU.
Other Privacy Laws
Restrictions on Record Collecting
In the US, the government has strict guidelines on how much information can be collected about its citizens. Certain classes of information have been restricted by laws over time, and the advent of digital tools has made these restrictions more important than ever.
Children’s Online Privacy Protection Act
Websites that are collecting information from children under the age of thirteen are required to comply with the Children’s Online Privacy Protection Act (COPPA), which is enforced by the Federal Trade Commission (FTC). To comply with COPPA, organizations must make a good-faith effort to determine the age of those accessing their websites and, if users are under thirteen years old, must obtain parental consent before collecting any information.
Family Educational Rights and Privacy Act
The Family Educational Rights and Privacy Act (FERPA) is a US law that protects the privacy of student education records. In brief, this law specifies that parents have a right to their child’s educational information until the child reaches either the age of eighteen or begins attending school beyond the high school level. At that point, control of the information is given to the child. While this law is not specifically about the digital collection of information on the Internet, the educational institutions that are collecting student information are at a higher risk for disclosing it improperly because of digital technologies.
Health Insurance Portability and Accountability Act
The Health Insurance Portability and Accountability Act of 1996 (HIPAA) is the law that specifically singles out records related to health care as a special class of personally identifiable information. This law gives patients specific rights to control their medical records, requires health care providers and others who maintain this information to get specific permission in order to share it, and imposes penalties on the institutions that breach this trust. Since much of this information is now shared via electronic medical records, the protection of those systems becomes paramount.
Non-Obvious Relationship Awareness
Digital technologies have given us many new capabilities that simplify and expedite the collection of personal information. Every time we come into contact with digital technologies, information about us is being made available. From our location to our web-surfing habits, our criminal record to our credit report, we are constantly being monitored. This information can then be aggregated to create profiles of each and every one of us. While much of the information collected was available in the past, collecting it and combining it took time and effort. Today, detailed information about us is available for purchase from different companies. Even information not categorized as PII can be aggregated in such a way that an individual can be identified.
This process of collecting large quantities of a variety of information and then combining it to create profiles of individuals is known as non-obvious relationship awareness or NORA. First commercialized by big casinos looking to find cheaters, NORA is used by both government agencies and private organizations, and it is big business.
In some settings, NORA can bring many benefits, such as in law enforcement. By being able to identify potential criminals more quickly, crimes can be solved more quickly or even prevented before they happen. But these advantages come at a price: our privacy.
Study Questions
- What does the term information systems ethics mean?
- What is a code of ethics? What are one advantage and one disadvantage of a code of ethics?
- What does the term intellectual property mean? Give an example.
- What protections are provided by copyright? How do you obtain one?
- What is fair use?
- What protections are provided by a patent? How do you obtain one?
- What does a trademark protect? How do you obtain one?
- What does the term personally identifiable information mean?
- What protections are provided by HIPAA, COPPA, and FERPA?
- How would you explain the concept of NORA?
Exercises
- Provide one example of how information technology has created an ethical dilemma that would not have existed before the advent of information technology.
- Find an example of a code of ethics or acceptable use policy related to information technology and highlight five points that you think are important.
- Do some original research on the effort to combat patent trolls. Write a two-page paper that discusses this legislation.
- Give an example of how NORA could be used to identify an individual.
- How are intellectual property protections different across the world? Pick two countries and do some original research, then compare the patent and copyright protections offered in those countries to those in the US. Write a two to three pages paper describing the differences.


9.7: Remaining Loan Balance
With loans, it is often desirable to determine what the remaining loan balance will be after some number of years. For example, if you purchase a home and plan to sell it in five years, you might want to know how much of the loan balance you will have paid off and how much you have to pay from the sale.
To determine the remaining loan balance after some number of years, we first need to know the loan payments, if we don’t already know them. Remember that only a portion of your loan payments go towards the loan balance; a portion is going to go towards interest. For example, if your payments were $1,000 a month, after a year you will not have paid off $12,000 of the loan balance.
To determine the remaining loan balance, we can think “how much loan will these loan payments be able to pay off in the remaining time on the loan?”
If a mortgage at a 6% interest rate has payments of $1,000 a month, how much will the loan balance be 10 years from the end the loan?
Solution
To determine this, we are looking for the amount of the loan that can be paid off by $1,000 a month payments in 10 years. In other words, we’re looking for \(P_0\) when
\(\begin{array}{ll} d = \$1,000 & \text{the monthly loan payment} \\ r = 0.06 & 6\% \text{ annual rate} \\ k = 12 & \text{since we’re doing monthly payments, we’ll compound monthly} \\ N = 10 & \text{since we’re making monthly payments for 10 more years} \end{array} \)
\[\begin{align*} P_{0} & =\dfrac{1000\left(1-\left(1+\dfrac{0.06}{12}\right)^{-10(12)}\right)}{\left(\dfrac{0.06}{12}\right)}
\\[4pt] &=\dfrac{1000\left(1-(1.005)^{-120}\right)}{(0.005)}
\\[4pt] &=\dfrac{1000\left(1-(1.005)^{-120}\right)}{(0.005)}
\\[4pt] &=\dfrac{1000(1-0.5496)}{(0.005)}
\\[4pt] &=\$ 90,073.45 \end{align*} \nonumber \]
The loan balance with 10 years remaining on the loan will be \(\$ 90,073.45\)
Often times answering remaining balance questions requires two steps:
- Calculating the monthly payments on the loan
- Calculating the remaining loan balance based on the remaining time on the loan
A couple purchases a home with a \(\$ 180,000\) mortgage at \(4 \%\) for 30 years with monthly payments. What will the remaining balance on their mortgage be after 5 years?
Solution
First we will calculate their monthly payments.
We’re looking for \(d\).
\(\begin{array}{ll} r = 0.04 & 4\% \text{ annual rate} \\ k = 12 & \text{since they’re paying monthly} \\ N = 30 & \text{30 years} \\ P_0 = \$180,000 & \text{the starting loan amount} \end{array} \)
We set up the equation and solve for \(d\).
\[ \begin{align*} 180,000 &=\dfrac{d\left(1-\left(1+\dfrac{0.04}{12}\right)^{-30(12)}\right)}{\left(\dfrac{0.04}{12}\right)}
\\[4pt] 180,000 &=\dfrac{d\left(1-(1.00333)^{-360}\right)}{(0.00333)}
\\[4pt] 180,000 &=d(209.562)
\\[4pt] d &=\dfrac{180,000}{209.562}
\\[4pt] &=\$ 858.93 \end{align*} \nonumber \]
Now that we know the monthly payments, we can determine the remaining balance. We want the remaining balance after 5 years, when 25 years will be remaining on the loan, so we calculate the loan balance that will be paid off with the monthly payments over those 25 years.
\(\begin{array}{ll} d = \$858.93 & \text{the monthly loan payment we calculated above} \\ r = 0.04 & 4\% \text{ annual rate} \\ k = 12 & \text{since they’re paying monthly} \\ N = 25 & \text{since they’d be making monthly payments for 25 more years} \end{array} \)
\[\begin{align*} P_{0} &=\dfrac{858.93\left(1-\left(1+\dfrac{0.04}{12}\right)^{-25(12)}\right)}{\left(\dfrac{0.04}{12}\right)}
\\[4pt] &=\dfrac{858.93\left(1-(1.00333)^{-300}\right)}{(0.00333)}
\\[4pt] &=\dfrac{858.93(1-0.369)}{(0.00333)}
\\[4pt] & \approx \$ 162,758 \end{align*} \nonumber \]
The loan balance after 5 years, with 25 years remaining on the loan, will be \(\$ 162,758\)
Over that 5 years, the couple has paid off \(\$ 180,000-\$ 162,758=\$ 17,242\) of the loan balance. They have paid a total of \(\$ 858.93\) a month for 5 years ( 60 months), for a total of \(\$ 51,535.80\), so \(\$ 51,535.80-\$ 17,242=\$ 34,292.80\) of what they have paid so far has been interest.


5.6: Periods of Greek History
Historians today separate Greek history into particular periods, which shared specific features throughout the Greek world:
The Bronze Age (c. 3,300 – 1,150 BCE) – a period characterized by the use of bronze tools and weapons. In addition, two particular periods during the Bronze Age are crucial in the development of early Greece: the Minoan Age on the island of Crete (c. 2,000 – 1,450 BCE) and the Mycenean period on mainland Greece (c. 1,600 – 1,100 BCE), both of them characterized by massive palaces, remnants of which still proudly stand today. The Minoan and Mycenaean civilizations had writing (dubbed Linear A and Linear B , respectively), which they used for keeping lists and palace inventories.
The Dark Ages (c. 1,100 – 700 BCE) – a period that is “dark” from the archaeological perspective, which means that the monumental palaces of the Mycenean period disappear, and the archaeological record reveals a general poverty and loss of culture throughout the Greek world. For instance, the Linear A and Linear B writing systems disappear. The Greeks do not rediscover writing until the invention of the Greek alphabet at the end of the Dark Ages or the early Archaic Period.
Archaic Period (c. 700 – 480 BCE) – the earliest period for which written evidence survives; this is the age of the rise of the Greek city-states, colonization, and the Persian Wars.
Classical Period (c. 480 – 323 BCE) – the period from the end of the Persian Wars to the death of Alexander the Great . One of the most important events during this period is the Peloponnesian War (431 – 404 BCE), which pitted Athens against Sparta, and forced all other Greek city-states to choose to join one side or the other. This period ends with the death of Alexander the Great, who had unified the Greek world into a large kingdom with himself at its helm.
Hellenistic Period (323 – 146 BCE) – the period from the death of Alexander to the Roman conquest of Greece; this is the age of the Hellenistic monarchies ruling over territories previously conquered by Alexander and his generals. Some historians end this period in 30 BCE, with the death of Cleopatra VII , the last surviving ruler of Egypt who was a descendant of one of Alexander’s generals.
The rest of this chapter will be devoted to examining each of these periods in greater detail, covering chief political, military, and cultural developments.


Describe the impact of different parenting styles on children’s development
Parenting Styles
Relationships between parents and children continue to play a significant role in children’s development during early childhood. We will explore two models of parenting styles. Keep in mind that most parents do not follow any model completely. Real people tend to fall somewhere in between these styles. And sometimes parenting styles change from one child to the next or in times when the parent has more or less time and energy for parenting. Parenting styles can also be affected by concerns the parent has in other areas of their life. For example, parenting styles tend to become more authoritarian when parents are tired and perhaps more authoritative when they are more energetic. Sometimes parents seem to change their parenting approach when others are around, maybe because they become more self-conscious as parents or are concerned with giving others the impression that they are a “tough” parent or an “easy-going” parent. And of course, parenting styles may reflect the type of parenting someone saw modeled while growing up.
Baumrind’s Parenting Styles
Baumrind (1971) offers a model of parenting that includes three styles. The first,
authoritarian
, is the traditional model of parenting in which parents make the rules and children are expected to be obedient. Baumrind suggests that authoritarian parents tend to place maturity demands on their children that are unreasonably high and tend to be aloof and distant. Consequently, children reared in this way may fear rather than respect their parents and, because their parents do not allow discussion, may take out their frustrations on safer targets – perhaps as bullies toward peers.
Permissive parenting
involves being a friend to a child rather than an authority figure. Children are allowed to make their own rules and determine their own activities. Parents are warm and communicative but provide little structure for their children. Children may fail to learn self-discipline and may feel somewhat insecure because they do not know the limits.
Authoritative parenting
involves being appropriately strict, reasonable, and affectionate. Parents allow negotiation where appropriate and discipline matches the severity of the offense. A popular parenting program that is offered in many school districts is called “Love and Logic” and reflects the authoritative or democratic style of parenting just described.
Today we recognize a fourth style within the Baumrind framework:
uninvolved parenting.
These parents are disengaged from their children. They do not make demands on their children and are non-responsive. These children can suffer in school and in their relationships with their peers (Gecas & Self, 1991).
Lemasters and Defrain’s Parenting Model
Lemasters and Defrain (1989) offered yet another model of parenting. This model is interesting because it looks more closely at the motivations of the parent and suggests that parenting styles are often designed to meet the psychological needs of the parent rather than the developmental needs of the child.
The
martyr
is a parent who will do anything for the child, even tasks that the child should do for himself or herself. All of the good deeds performed for the child, in the name of being a “good parent,” may be used later should the parent want to gain compliance from the child. If a child goes against the parent’s wishes, the parent can remind the child of all of the times the parent helped the child and evoke a feeling of guilt so that the child will do what the parent wants. The child learns to be dependent and manipulative as a result. (Beware, a parent busy whipping up cookies may really be thinking “control”!)
The
pal
is like the permissive parent described in Baumrind’s model above. The pal wants to be the child’s friend. Perhaps the parent is lonely, or perhaps the parent is trying to win a popularity contest against an ex-spouse. Pals let children do what they want and focus most on being entertaining and fun. They set few limitations. Consequently, the child may have little self-discipline and may try to test limits with others.
The
police officer/drill sergeant
style of parenting is similar to the authoritarian parent described above. The parent focuses primarily on making sure that the child is obedient and that the parent has full control of the child. Sometimes this can be taken to extremes by giving the child tasks that are really designed to check on their level of obedience. For example, the parent may require that the child fold the clothes and place items back in the drawer in a particular way. If not, the child might be scolded or punished for not doing things “right.” This type of parent has a very difficult time allowing the child to grow and learn to make decisions independently. And the child may have a lot of resentment toward the parent that is displaced on others.
The
teacher-counselor
parent is one who pays a lot of attention to expert advice on parenting and who believes that as long as all of the steps are followed, the parent can rear a perfect child. “What’s wrong with that?” you might ask. There are two major problems with this approach. First, the parent is taking all of the responsibility for the child’s behavior, at least indirectly. If the child has difficulty, the parent feels responsible and thinks that the solution lies in reading more advice and trying more diligently to follow that advice. Parents can certainly influence children, but thinking that the parent is fully responsible for the child’s outcome is faulty. A parent can only do so much and can never have full control over the child. Another problem with this approach is that the child may get an unrealistic sense of the world and what can be expected from others. For example, if a teacher-counselor parent decides to help the child build self-esteem and has read that telling the child how special he or she is or how important it is to compliment the child on a job well done, the parent may convey the message that everything the child does is exceptional or extraordinary. A child may come to expect that all of his efforts warrant praise, and in the real world, this is not something one can expect. Perhaps children get more of a sense of pride from assessing their own performance than from having others praise their efforts.
So what is left? Lemasters and Defrain (1989) suggest that the
athletic coach style of parenting
is best. Before you draw conclusions here, set aside any negative experiences you may have had with coaches in the past. The principles of coaching are what are important to Lemasters and Defrain. A coach helps players form strategies, supports their efforts, gives feedback on what went right and what went wrong, and stands at the sideline while the players perform. Coaches and referees make sure that the rules of the game are followed and that all players adhere to those rules. Similarly, the athletic coach as parent helps the child understand what needs to happen in certain situations whether in friendships, school, or home life and encourages and advises the child about how to manage these situations. The parent does not intervene or do things for the child. Rather, the parent’s role is to provide guidance while the child learns first hand how to handle these situations. The rules for behavior are consistent and objective and presented in that way. So, a child who is late for dinner might hear the parent respond in this way, “Dinner was at six o’clock.” Rather than, “You know good and well that we always eat at six. If you expect me to get up and make something for you now, you have got another thing coming! Just who do you think you are showing up late and looking for food? You’re grounded until further notice!”
The most important thing to remember about parenting is that you can be a better, more objective parent when you are directing your actions toward the child’s needs while considering what they can reasonably be expected to do at their stage of development. Parenting is more difficult when you are tired and have psychological needs that interfere with the relationship. Some of the best advice for parents is to try not to take the child’s actions personally, and be as objective as possible.
Class and Culture
The impact of class and culture cannot be ignored when examining parenting styles. The two models of parenting described above assume that authoritative and athletic coaching styles are best because they are designed to help the parent raise a child who is independent, self-reliant, and responsible. These are qualities favored in “individualistic” cultures such as the United States, particularly by the middle class.
Authoritarian parenting has been used historically and reflects the cultural need for children to do as they are told. African-American, Hispanic, and Asian parents tend to be more authoritarian than non-Hispanic whites. In collectivistic cultures such as China or Korea, being obedient and compliant are favored behaviors. In societies where family members’ cooperation is necessary for survival, as in the case of raising crops, rearing children who are independent and who strive to be on their own makes no sense. But in an economy based on being mobile in order to find jobs and where one’s earnings are based on education, raising a child to be independent is very important.
Working class parents are more likely than middle-class parents to focus on obedience and honesty when raising their children. In a classic study on social class and parenting styles called
Class and Conformity
, Kohn (1977) explained that parents tend to emphasize qualities that are needed for their own survival when parenting their children. Working class parents are rewarded for being obedient, reliable, and honest in their jobs. They are not paid to be independent or to question the management; rather, they move up and are considered good employees if they show up on time, do their work as they are told, and can be counted on by their employers. Consequently, these parents reward honesty and obedience in their children. Middle-class parents who work as professionals are rewarded for taking initiative, being self-directed, and assertive in their jobs. They are required to get the job done without being told exactly what to do. They are asked to be innovative and to work independently. These parents encourage their children to have those qualities as well by rewarding independence and self-reliance. Parenting styles can reflect many elements of culture.
Link to Learning
In
Scout O’Donnell’s TED Talk,
she describes the alternative parenting style used by her parents. Can you find elements of authoritative and coaching parenting, along with a little Love and Logic?
About 75.7 percent of mothers of school-aged and 65.1 percent of mothers of preschool aged children in the United States work outside the home
[1]
. Since more women have been entering the workplace, there has been a concern that families do not spend as much time with their children. This, however, may not be true. Between 1981 and 1997, the amount of time that parents spent with children increased overall (Sandberg and Hofferth, 2001). Modern numbers for this vary widely, as many parents who work outside of the home also devote significant amounts of time to childcare, to 14 hours a week, compared with 10 in 1965.
[2]
The amount of this time that is undistracted and involved may be close to 34 minutes a day.
[3]
Seventy-five percent of children under age 5 are in scheduled child care programs. Others are cared for by family members, friends, or are in Head Start Programs. Older children are often in after school programs, before school programs, or stay at home alone after school once they are older. Quality childcare programs can enhance a child’s social skills and can provide rich learning experiences. But long hours in poor quality care can have negative consequences for young children in particular. What determines the quality of child care? One very important consideration is the teacher/child ratio. States specify the maximum number of children that can be supervised by one teacher. In general, the younger the children, the more teachers required for a given number of children. The lower the teacher to child ratio, the more time the teacher has for involvement with the children and the less stressed the teacher may be so that the interactions can be more relaxed, stimulating and positive. The more children there are in a program, the less desirable the program as well. This is because the center may be more rigid in rules and structure to accommodate the large number of children in the facility.
The physical environment should be colorful, stimulating, clean, and safe. The philosophy of the organization and the curriculum available should be child-centered, positive, and stimulating. Providers should be trained in early childhood education as well. A majority of states do not require training for their child care providers. And while formal education is not required for a person to provide a warm, loving relationship to a child, knowledge of a child’s development is useful for addressing their social, emotional, and cognitive needs in an effective way. By working toward improving the quality of childcare and increasing family-friendly workplace policies, such as more flexible scheduling and perhaps childcare facilities at places of employment, we can accommodate families with smaller children and relieve parents of the stress sometimes associated with managing work and family life.
Global Concerns: The Market Women of Liberia
Work and mothering go hand in hand in many parts of the world. Consider the market women of Liberia. These are women who work as street vendors and are primary providers for their families.  Recently, they have been supported by President Sirleaf whose grandmother was a market woman. President Sirleaf has worked to raise funds to improve the marketplaces and conditions for mothers and children. The hope has been to make these marketplaces more safe, to provide childcare, and social services to improve the lives of mothers and children (Nance-Nash, 2009).
This video on the Sirleaf Market Women’s Fund
explains more.
the rules for behavior are consistent and objective and presented in that way. The parent’s role is to provide guidance while the child learns first hand how to handle these situations
authoritarian parenting
the traditional model of parenting in which parents make the rules and children are expected to be obedient
authoritative parenting
appropriately strict, reasonable, and affectionate. They are willing to negotiate when appropriate
martyr parent
parent who will do anything for the child, even tasks that the child should do independently, may later use what they have done for the child to invoke guilt and compliance
pal parent
wants to be the child’s friend and focuses being entertaining and fun
permissive parenting
involves being a friend to a child rather than an authority figure. Children are allowed to make their own rules and determine their own activities
police officer/drill sergeant parent
focuses primarily on making sure that the child is obedient and that the parent has full control of the child
teacher-counselor parent
pays a lot of attention to expert advice on parenting and believes that as long as all of the steps are followed, the parent can rear a perfect child
uninvolved parenting
parents who are disengaged from their children, do not make demands on their children, and are non-responsive
Modification, adaptation, and original content.
Authored by
: Stephanie Loalada for Lumen Learning.
Provided by
: Lumen Learning.
License
:
CC BY: Attribution


15.5: Other Quantitative Analysis
-
- Last updated
- Save as PDF
There are many other useful inferential statistical techniques—based on variations in the GLM—that are briefly mentioned here. Interested readers are referred to advanced textbooks or statistics courses for more information on these techniques:
Factor analysis is a data reduction technique that is used to statistically aggregate a large number of observed measures (items) into a smaller set of unobserved (latent) variables called factors based on their underlying bivariate correlation patterns. This technique is widely used for assessment of convergent and discriminant validity in multi-item measurement scales in social science research.
Discriminant analysis is a classificatory technique that aims to place a given observation in one of several nominal categories based on a linear combination of predictor variables. The technique is similar to multiple regression, except that the dependent variable is nominal. It is popular in marketing applications, such as for classifying customers or products into categories based on salient attributes as identified from large-scale surveys.
Logistic regression (or logit model) is a GLM in which the outcome variable is binary (0 or 1) and is presumed to follow a logistic distribution, and the goal of the regression analysis is to predict the probability of the successful outcome by fitting data into a logistic curve. An example is predicting the probability of heart attack within a specific period, based on predictors such as age, body mass index, exercise regimen, and so forth. Logistic regression is extremely popular in the medical sciences. Effect size estimation is based on an ‘odds ratio’, representing the odds of an event occurring in one group versus the other.
Probit regression (or probit model) is a GLM in which the outcome variable can vary between 0 and 1—or can assume discrete values 0 and 1—and is presumed to follow a standard normal distribution, and the goal of the regression is to predict the probability of each outcome. This is a popular technique for predictive analysis in the actuarial science, financial services, insurance, and other industries for applications such as credit scoring based on a person’s credit rating, salary, debt and other information from their loan application. Probit and logit regression tend to demonstrate similar regression coefficients in comparable applications (binary outcomes), however the logit model is easier to compute and interpret.
Path analysis is a multivariate GLM technique for analysing directional relationships among a set of variables. It allows for examination of complex nomological models where the dependent variable in one equation is the independent variable in another equation, and is widely used in contemporary social science research.
Time series analysis is a technique for analysing time series data, or variables that continually changes with time. Examples of applications include forecasting stock market fluctuations and urban crime rates. This technique is popular in econometrics, mathematical finance, and signal processing. Special techniques are used to correct for autocorrelation, or correlation within values of the same variable across time.


13.5: Conclusion
selected template will load here
This action is not available.
The aim of the chapter was to show how, in various parts of the world, the voices of ordinary people – intensified and encouraged by globalisation and the attendant communications revolution – challenged the status quo. In some cases this resulted in significant regime change; in others, rulers were able to hang on to power. While the picture may appear more gloomy than cheerful in terms of evidence of change, it is important to understand that none of the examples of the protests covered in this chapter are definitively concluded. Unlike earlier revolutions – for example, those in France, Russia and China, all of which ushered in definitive regime changes – none of the examples covered in this chapter amount to clear-cut jumps from one political system to another. What we can observe is the connectedness and shared ideas that collectively characterise today’s popular protests. We can expect to see more such protests in the years to come as people across the world raise their voices and demand change.