case study questions on nervous system

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Chapter 8 Answers: Nervous System

8.2 introduction to the nervous system review questions and answers.

• List the general steps through which the nervous system generates an appropriate response to information from the internal and external environments.  The nervous system extracts information from the internal and external environments using sensory receptors. It then usually sends signals encoding this information to the brain, which processes the information to determine an appropriate response. Finally, the brain sends signals to muscles, organs, or glands to bring about the response.
• What are neurons? Neurons are special nervous system cells that transmit nerve impulses.
• Compare and contrast the central and peripheral nervous systems. The central and peripheral nervous systems are the two main divisions of the nervous system. The central nervous system includes the brain and spinal cord, whereas the peripheral nervous system consists mainly of nerves that connect the central nervous system with the rest of the body.
• Self-marking
• Which major division of the peripheral nervous system allows you to walk to class? Which major division of the peripheral nervous system controls your heart rate?  The somatic nervous system is the major division of the peripheral nervous system that allows you walk to class. The autonomic nervous system controls your heart rate.
• Identify the functions of the three main divisions of the autonomic nervous system.  The function of the sympathetic division of the autonomic nervous system is primarily to control the fight-or-flight response in emergency situations. The function of the parasympathetic division is to control the routine “housekeeping” functions of the body at other times. The function of the enteric division is to provide local control of the digestive system.
• What is an axon, and what is its function? An axon is a long projection of a neuron that transmits nerve impulses to other cells.
• Define nerve impulses. Nerve impulses are the electrical signals sent by the nervous system.
• Explain generally how the brain and spinal cord can interact with and control the rest of the body. Answers may vary. Sample answer:  The brain and spinal cord (i.e. the CNS) can interact and control the rest of the body through the nerves of the PNS.
• How are nerves and neurons related? Nerves are bundles of axons from neurons.
• What type of information from the outside environment do you think is detected by sensory receptors in your ears? Answers may vary. Sample answer:  I think sensory receptors in your ears detect sounds/sound waves.

8.3 Neurons and Glial Cells Review Questions and Answers

• Describe the myelin sheath and nodes of Ranvier. How does their arrangement allow nerve impulses to travel very rapidly along axons? The myelin sheath consists of the lipid layers that cover sections of an axon. Nodes of Ranvier are regularly spaced gaps between sections of myelin sheath along the axon. Myelin sheath is a good insulator, so nerve impulses can travel along a myelinated axon by skipping from node to node, allowing nerve impulses to travel along the axon very rapidly.
• Define neurogenesis. What is the potential for neurogenesis in the human brain? Neurogenesis is the creation of new nerve cells by cell division. This occurs prenatally when the brain is still forming and growing. However, once the brain is mature, if neurogenesis occurs, its extent is not likely to be very great in humans.
• Relate neurons to different types of nervous tissues. Gray matter is nervous tissue in the central nervous system that consists mainly of unmyelinated structures such as the cell bodies and dendrites of neurons. White matter is nervous tissue found in the central nervous system and in nerves of the peripheral nervous system that consists mainly of myelinated axons. The axons in each nerve are bundled together like wires in a cable.
• Compare and contrast sensory and motor neurons. Both sensory and motor neurons carry nerve impulses in the peripheral nervous system between the central nervous system and the rest of the body. However, they carry nerve impulses in different directions. Sensory neurons carry nerve impulses away from the body and toward the brain, whereas motor neurons carry nerve impulses away from the brain and toward the body.
• Identify the role of interneurons. The role of interneurons is to carry nerve impulses back and forth mainly between sensory neurons and motor neurons.
• Identify four specific functions of neuroglia. Answers may vary. Sample answer:  Four specific functions of glial cells are to synthesize myelin, hold neurons in place, supply neurons with nutrients, and regulate the repair of neurons.
• What is the relationship between the proportion of neuroglia to neurons and intelligence? In general, the greater the proportion of neuroglia to neurons, the greater the level of intelligence. This may be true between individuals within a species and also between different species.

8.4 Nerve Impulses Review Questions and Answers

• Define nerve impulse. A nerve impulse is an electrical phenomenon that occurs because of a difference in electrical charge across the plasma membrane of a neuron. It is a sudden reversal of the electrical gradient across the membrane.
• What is the resting potential of a neuron, and how is it maintained? The resting potential of a neuron is an electrical gradient across the plasma membrane of a neuron that is not actively transmitting a nerve impulse. The resting potential is maintained by the sodium-potassium pump, which pumps ions across the cell membrane against their concentration gradients using energy in ATP and transport proteins in the plasma membrane.
• Explain how and why an action potential occurs. An action potential occurs when there is a sudden reversal of the electrical gradient across the plasma membrane of a resting neuron. It travels rapidly down the axon as an electrical current. An action potential occurs because the neuron receives a chemical signal from another cell or some other type of stimulus.
• Outline how a signal is transmitted from a presynaptic cell to a postsynaptic cell at a chemical synapse.  At a chemical synapse, neurotransmitter chemicals are released from the presynaptic cell into the synaptic cleft between cells. The chemicals travel across the synaptic cleft to the postsynaptic cell and bind to receptors embedded in its membrane.
• What generally determines the effects of a neurotransmitter on a postsynaptic cell? The effects of a neurotransmitter on a postsynaptic cell are generally determined by the type of receptor they bind to.
• Identify three general types of effects that neurotransmitters may have on postsynaptic cells. Three general types of effects neurotransmitters may have on postsynaptic cells are excitatory effects, inhibitory effects, and effects that change the cell in more complex ways.
• Explain how an electrical signal in a presynaptic neuron causes the transmission of a chemical signal at the synapse. An action potential is a type of electrical signal. When it reaches the axon terminal of the presynaptic cell, it opens channels that allow calcium to enter the terminal. Calcium causes synaptic vesicles to fuse with the membrane, releasing their contents (chemical neurotransmitter molecules) into the synaptic cleft. This chemical signal then travels to the postsynaptic cell. In this way, an electrical signal in a presynaptic cell gets translated into a chemical signal at the synapse.
• The flow of which type of ion into a neuron results in an action potential? How do these ions get into the cell? What does this flow of ions do to the relative charge inside the neuron compared to the outside?  Sodium ions.  They flow through sodium ion channels in the cell membrane that have opened in response to a signal or stimulation. The inside of the neuron becomes more positive compared to the outside.
• Name three neurotransmitters. Answers may vary. Sample answer:  Glutamate, GABA, and serotonin.

8.5 Central Nervous System Review Questions and Answers

• What is the central nervous system? The central nervous system is the part of the nervous system that includes the brain and spinal cord.
• How is the central nervous system protected? The central nervous system is protected physically by bones, meninges, and cerebrospinal fluid. It is protected chemically by the blood-brain barrier.
• What is the overall function of the brain? The overall function of the brain is to act as the control centre of the entire organism.
• Identify the three main parts of the brain and one function of each part. Answers may vary. Sample answer:  The three main parts of the brain are the brain stem, which controls vital functions such as breathing; cerebellum, which coordinates body movements; and cerebrum, which controls conscious thoughts.
• Describe the hemispheres of the brain. The hemispheres are the right and left halves of the cerebrum, which are connected by a thick bundle of axons called the corpus callosum. The two hemispheres are similar in shape, and most areas of the cerebrum are found in both hemispheres.
• Explain and give examples of lateralization of the brain. Lateralization refers to differences between brain hemispheres in particular functions. For example, in most people, language functions are more concentrated in the left hemisphere, whereas abstract reasoning and visual-spatial abilities are more concentrated in the right hemisphere.
• Identify one function of each of the four lobes of the cerebrum. Answers may vary. Sample answer:  The frontal lobe controls reasoning. The parietal lobe controls touch. The temporal lobe controls hearing. The occipital lobe controls vision.
• Summarize the structure and function of the cerebral cortex. Explain how the hypothalamus controls the endocrine system. The cerebral cortex is a thin layer of gray matter on the outside of the cerebrum and contains many folds that greatly increase its surface area. It is the part of the brain where most information processing takes place.
• Describe the spinal cord. The spinal cord is a long, thin, tubular bundle of nervous tissue that extends from the brainstem and continues down the centre of the back to the pelvis. It is enclosed within the vertebral column. The centre of the spinal cord contains gray matter, and this is surrounded by white matter.
• What is the main function of the spinal cord? The main function of the spinal cord is to pass nerve impulses back and forth between the brain and the body.
• Explain how reflex actions occur. Reflex actions occur when sensory nerves send impulses that go to the spinal cord and from the spinal cord go to motor nerves without traveling all the way to the brain and back.
• Why do severe spinal cord injuries usually cause paralysis? Severe spinal cord injuries usually cause paralysis because they interrupt the transmission of sensory nerve messages to the brain and motor nerve messages from the brain.
• What do you think are some possible consequences of severe damage to the brain stem? How might this compare to the consequences of severe damage to the frontal lobe? Explain your answer. Answers will vary. Sample answer:  I think that severe damage to the brain stem is likely to be life-threatening, because it controls unconscious vital functions of the body, such as heart rate and breathing. Severe damage to the frontal lobe would be less likely to be life-threatening because it is involved in higher level executive functions such as planning and problem solving. It may, however, cause problems with these functions as well as abstract thought, language, attention, self-control and personality because the frontal lobe is involved in all of these functions.
• Information travels very quickly in the nervous system, but generally, the longer the path between areas, the longer it takes. Based on this, explain why you think reflexes often occur at the spinal cord level, and do not require input from the brain. Answers will vary. Sample answer:  Reflexes often occur to protect us from harm. For instance, there is a reflex that causes you to pull your arm back when you touch something that is too hot. This needs to happen very quickly so that we don’t get hurt. If the information had to travel to the brain before the arm could be moved, the response might be too slow and damage could occur. Therefore, spinal reflexes that don’t require input from the brain allow us to respond more quickly to harmful stimuli.

8.6 Peripheral Nervous System Review Questions and Answers

• Describe the general structure of the peripheral nervous system. State its primary function. The peripheral nervous system consists of all the nervous tissue that lies outside of the central nervous system. It consists of ganglia and nerves. The primary function of the peripheral nervous system is to connect the central nervous system to the rest of the organism.
• What are ganglia? Ganglia are groups of cell bodies in the PNS.
• Identify three types of nerves based on the direction in which they carry nerve impulses.  Three types of nerves based on the direction in which they carry nerve impulses are: sensory nerves, which carry nerve impulses from the body to the CNS; motor nerves, which carry impulses from the CNS to the body; and mixed nerves, which contain both sensory and motor neurons.
• Outline all of the divisions of the peripheral nervous system. The two major divisions of the peripheral nervous system are the somatic and autonomic nervous systems. The autonomic system, in turn, is divided into sympathetic, parasympathetic, and enteric divisions.
• Compare and contrast the somatic and autonomic nervous systems. The somatic and autonomic nervous systems are the two main divisions of the peripheral nervous system. The somatic nervous system primarily senses the external environment and controls voluntary activities, generally under control of the cerebral cortex. The autonomic nervous system primarily senses the internal environment and controls involuntary activities, generally under control of the hypothalamus.
• When and how does the sympathetic division of the autonomic nervous system affect the body? The sympathetic division prepares the body to fight or flee when it is faced with danger. For example, it speeds up the heart rate, widens air passages in the lungs, increases blood flow to the skeletal muscles, and temporarily shuts down the digestive system.
• What is the function of the parasympathetic division of the autonomic nervous system? Specifically, how does it affect the body?  The function of the parasympathetic division of the autonomic nervous system is to return the body to normal after a fight-or-flight response and to maintain internal homeostasis of the body at other times. Specifically, the parasympathetic division slows down the heart rate, narrows air passages in the lungs, reduces blood flow to the skeletal muscles, and stimulates the digestive system to start working again.
• Name and describe two peripheral nervous system disorders. Answers may vary. Sample answer:  Two disorders of the peripheral nervous system include Guillain-Barre syndrome and Charcot-Marie-Tooth disease. In Guillain-Barre syndrome, the immune system attacks nerves of the PNS, leading to muscle weakness and paralysis. The exact cause is unknown, but it appears to be linked to an infection. Most people eventually make a full recovery. Charcot-Marie-Tooth disease is an incurable hereditary disorder that affects predominantly the nerves in the feet and legs. It is characterized by loss of muscle tissue and sense of touch.
• Give one example of how the CNS interacts with the PNS to control a function in the body. Answers will vary. Sample answer: The cerebral cortex of the brain, which is in the CNS, commands the somatic nervous system of the PNS to carry out voluntary motor activities.
• Visual information sensory, somatic
• Blood pressure information  sensory, autonomic
• Information that causes muscle contraction in digestive organs after eating motor, autonomic
• Information that causes muscle contraction in skeletal muscles based on the person’s decision to make a movement motor, somatic

8.7 Human Senses Review Questions and Answers

• Compare and contrast special senses and general senses. Special senses have specialized sense organs and include vision (eyes), hearing (ears), balance (ears), taste (tongue), and smell (nasal passages). General senses are all associated with touch and lack special sense organs. Instead, touch receptors are found throughout the body, particularly in the skin.
• What are sensory receptors? Sensory receptors are specialized nerve cells that respond to stimuli in the internal or external environment and transform them into nerve impulses.
• Describe the range of tactile stimuli detected in the sense of touch.  Tactile stimuli that are detected in the sense of touch include pressure, vibration, temperature, and pain.
• Explain how the eye collects and focuses light to form an image, and how it converts it to nerve impulses. Light passes first through the cornea, which helps to focus the light by refracting it. Light next enters the interior of the eye through an opening called the pupil. Light then passes through the lens, which refracts the light even more and focuses it on the retina at the back of the eye. The retina contains photoreceptor cells called rods and cones that convert the light that strikes them into nerve impulses.
• Identify two common vision problems,along with their causes and their effects on vision.  Answers may vary. Sample answer:  Two common vision problems are myopia and hyperopia. Myopia occurs when the eyeball is too long or the cornea is too curved, causing distant objects to be out of focus without affecting near vision. Hyperopia occurs when the eyeball is too long or the lens is not curved enough, causing close objects to be out of focus without affecting distant vision.
• Explain how structures of the ear collect and amplify sound waves and transform them to nerve impulses. Sound waves enter the ear canal and strike the eardrum, causing it to vibrate. The vibrations are passed through and amplified by the three tiny bones (hammer, anvil, and stirrup) of the middle ear, which passes the amplified vibrations to the fluid-filled cochlea in the inner ear. The vibrations make waves in the fluid inside the cochlea, which bends the tiny hair cells lining it. The bending of the hair cells causes them to generate nerve impulses.
• What role does the ear play in balance? Which structures of the ear are involved in balance? The semicircular canals in the ear contain fluid that moves when the head changes position. Tiny hairs lining the canals sense movement of the fluid. In response, they send nerve impulses to the vestibular nerve, which carries the impulses the brain.
• Describe two ways that the body senses chemicals. What are the special sense organs involved in these senses? Two ways the body senses chemicals are with the sense of taste and the sense of smell. Taste buds on the tongue contain chemoreceptors that sense chemicals in food. Olfactory chemoreceptors in the nasal passages sense chemicals in air.
• Explain why your skin can detect different types of stimuli, such as pressure and temperature. Answers may vary. Sample answer:  Human skin can detect different types of stimuli, because it contains several different types of receptors that respond to different kinds of stimuli by generating nerve impulses. For example, skin contains mechanoreceptors which detect mechanical force or touch, nociceptors that detect painful stimuli, and thermoreceptors that detect temperature.
• Is sensory information sent to the central nervous system via efferent or afferent nerves? Afferent
• Identify a mechanoreceptor used in two different human senses. Describe the type of mechanical stimuli that each detects. Answers may vary. Sample answer:  Hair cells in the ear are mechanoreceptors that detect sound waves by moving back and forth in the cochlea in response to transmission of sound within the ear. There are also mechanoreceptors in the skin that detect the mechanical stimulation of touch stimuli, such as pressure and vibration.
• If a person is blind, but their retina is functioning properly, where do you think the damage might be? Explain your answer. Answers may vary. Sample answer:  For a person to perceive visual stimuli, their brain must be able to interpret the information coming from their retina. Therefore, if a person is blind but their retina is functioning properly, there may be a problem later in the pathway to the brain, such as in the path the optic nerve takes, or in the visual cortex itself.
• When you see colours, what receptor cells are activated? Where are these receptors located? What lobe of the brain is primarily used to process visual information? Cone photoreceptors. Cones are located in the retina, particularly in the centre of the retina. The occipital lobe.
• The auditory nerve carries sound information .

8.8 Psychoactive Drugs Review Questions and Answers

• What are psychoactive drugs? Psychoactive drugs are substances that change the function of the brain and result in alterations of mood, thinking, perception, and/or behavior.
• Identify six classes of psychoactive drugs, along with an example of a drug in each class. Examples may vary. Sample answer:  Six classes of psychoactive drugs (and an example of each) are: stimulants (caffeine), depressants (ethanol), anxiolytics (diazepam), euphoriants (MDMA), hallucinogens (LSD), and empathogens (amphetamine).
• Compare and contrast psychoactive drugs that are agonists and psychoactive drugs that are antagonists.  Both agonists and antagonists produce their effects by affecting particular neurotransmitters in the brain. Agonists increase the activity of neurotransmitters, whereas antagonists decrease the activity of neurotransmitters.
• Describe two medical uses of psychoactive drugs. Answers may vary. Sample answer:  Two medical uses of psychoactive drugs are controlling pain and stabilizing mood.
• Give an example of a ritual use of a psychoactive drug. An example of a ritual use of a psychoactive drug is the use of the mescaline-containing peyote cactus for religious ceremonies by Native Americans.
• Generally speaking, why do people use psychoactive drugs recreationally? People generally use psychoactive drugs recreationally to alter their state of consciousness and create a feeling of euphoria.
• Define addiction. Addiction is the compulsive use of a drug despite negative consequences that such use may entail.
• Identify possible withdrawal symptoms associated with physical dependence on a psychoactive drug. Possible withdrawal symptoms associated with physical dependence on a psychoactive drug include tremors, pain, seizures, and insomnia.
• Why might a person with a heroin addiction be prescribed the psychoactive drug methadone? A person with a heroin addiction might be prescribed the psychoactive drug methadone to reduce their cravings and withdrawal symptoms.
• Is Prozac an agonist or an antagonist for serotonin? Explain your answer. It is an agonist for serotonin because it causes more serotonin to be present in the synapse, increasing the activation of serotonin receptors on the postsynaptic cell.
• Is Prozac a psychoactive drug? Explain your answer. Yes, Prozac is a psychoactive drug because it can alter a person’s mood.
• Name three classes of psychoactive drugs that include opioids. Depressants, anxiolytics, euphoriants
• True or False: All psychoactive drugs are either illegal or available by prescription only.  False
• True or False: Anxiolytics might be prescribed by a physician.  True
• Name two drugs that activate receptors for the neurotransmitter GABA. Why do you think these drugs generally have a depressant effect?  Answers may vary. Sample answer: Ethanol (alcohol) and barbiturates. GABA normally has an inhibitory effect on neurons, so activation of GABA receptors can cause a depressant effect.

8.9 Case Study Conclusion and Chapter 10 Summary Review Questions and Answers

• Which part of the brain is neuron A located in — the cerebellum, cerebrum, or brain stem? Explain how you know. Neuron A is in the cerebrum, because it is in the cerebral cortex which makes up the outer layer of the cerebrum.
• The cell body of neuron A is located in a lobe of the brain that is involved in abstract thought, problem solving, and planning. Which lobe is this? The frontal lobe
• Part of neuron A travels all the way down to the spinal cord to meet neuron B. Which part of neuron A travels to the spinal cord? The axon
• Neuron A forms a chemical synapse with neuron B in the spinal cord. How is the signal from neuron A transmitted to neuron B? When the action potential in neuron A reaches the axon terminal, it opens channels that allow calcium to enter the terminal. The calcium causes synaptic vesicles containing neurotransmitter to fuse with the membrane of the terminal. This releases neurotransmitter across the synaptic cleft to neurotransmitter receptors on neuron B. This is how the signal is transmitted from neuron A to neuron B.
• Is neuron A in the central nervous system (CNS) or peripheral nervous system (PNS)? CNS
• The axon of neuron B travels in a nerve to a skeletal muscle cell. Is the nerve part of the CNS or PNS? Is this an afferent nerve or an efferent nerve? PNS; efferent nerve
• What part of the PNS is involved in this pathway — the autonomic nervous system or the somatic nervous system? Explain your answer. The somatic nervous system, because this pathway controls a voluntary movement. The somatic nervous system controls voluntary activities and the autonomic nervous system controls involuntary activities.
• What are the differences between a neurotransmitter receptor and a sensory receptor? Answers may vary. Sample answer:  A neurotransmitter receptor is a protein embedded in the membrane of a postsynaptic cell that binds to neurotransmitter from the presynaptic cell. A sensory receptor is a specialized cell that responds to sensory stimuli and transmits the information to the CNS.
• If a person has a stroke and then has trouble using language correctly, which hemisphere of their brain was most likely damaged? Explain your answer. Answers may vary. Sample answer:  The left hemisphere of the brain was most likely damaged because in most people, language is concentrated (lateralized) on the left side. However, it can be different in different people.
• Define an electrical gradient, in the context of a cell. An electrical gradient is a difference in electrical charge across a cell membrane.
• What is responsible for maintaining the electrical gradient that results in the resting potential? The sodium-potassium pump
• Compare and contrast the resting potential and the action potential. Answers may vary. Sample answer:  The resting potential and action potential are both differences in electrical charge across the cell membrane of a neuron, but the resting potential is the electrical potential when the neuron is at rest, and the action potential occurs when a neuron becomes sufficiently stimulated or excited. Also, the action potential is a sudden reversal of the charge difference across the membrane compared to the resting potential. This makes the inside of the membrane more positive than the outside, as opposed to the typical negative resting membrane potential.
• Where along a myelinated axon does the action potential occur? Why does it happen here? Answers may vary. Sample answer:  In a myelinated axon, the action potential occurs at the nodes of Ranvier, which are unmyelinated gaps along the axon. This is because myelin is electrically insulating, preventing ions from flowing across, so the ion flow necessary for the action potential to occur can only happen at the nodes.
• What does it mean that the action potential is “all-or-none?” Answers may vary. Sample answer:  The action potential is said to be “all-or-none” because it either fully happens or it doesn’t happen at all. An action potential always occurs to the same extent, there are not smaller or larger action potentials.
• Compare and contrast Schwann cells and oligodendrocytes.  Schwann cells and oligodendrocytes are both glial cells in the nervous system that produce myelin sheath. However, Schwann cells are in the PNS, while oligodendrocytes are in the CNS.
• For the senses of smell and hearing, name their respective sensory receptor cells, what type of receptor cells they are, and what stimuli they detect. The sensory receptor cells for hearing are called hair cells, they are mechanoreceptors, and they detect sound waves. The sensory receptor cells for smell are called olfactory receptors, they are chemoreceptors, and they detect odor molecules.
• Nicotine is a psychoactive drug that binds to and activates a receptor for the neurotransmitter acetylcholine. Is nicotine an agonist or an antagonist for acetylcholine? Explain your answer. Nicotine is an agonist for acetylcholine because it activates an acetylcholine receptor, thereby mimicking its function.

Human Biology Copyright © 2020 by Christine Miller is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License , except where otherwise noted.

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Chapter 1:  Nervous System

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Functional classification of neurons, anatomical divisions of the nervous system.

• FUNCTIONAL DIVISIONS OF THE NERVOUS SYSTEM
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The neuron , or nerve cell, is the basic functional unit of the nervous system. A neuron includes its cell body and processes (axons and dendrites). Long neuronal processes are frequently referred to as fibers . Neurons are generally classified as either afferent or efferent:

Afferent , or sensory, neurons receive input from peripheral structures and transmit it to the spinal cord and/or brain.

Efferent , or motor, neurons transmit impulses from the brain and/or spinal cord to effectors (skeletal muscle, cardiac muscle, smooth muscle, glands) throughout the body.

The nervous system has two anatomical divisions:

The central nervous system (CNS) includes the brain and spinal cord.

The peripheral nervous system (PNS) consists of spinal nerves, their roots, and branches; cranial nerves (CN) and their branches; and components of the autonomic nervous system (ANS).

Collections of nerve cell bodies in the CNS form nuclei , whereas those in the PNS form ganglia . Ganglia and nuclei contain either motor or sensory neurons. Bundles of axons in the CNS are called tracts . Similar neuronal processes collected in the PNS form nerves . Nerves are categorized based on their CNS origin:

Spinal nerves are attached to the spinal cord. They transmit both motor and sensory impulses and are, thus, considered mixed nerves .

Most CN are attached to the brain. Some CN are either motor or sensory only, while others are mixed.

Spinal Nerves

The spinal cord is composed of segments, as indicated by the 31 pairs of spinal nerves. Each segment has numerous dorsal (posterior) and ventral (anterior) rootlets that arise from the respective surfaces of the spinal cord ( Fig. 1.1 ). Dorsal rootlets contain neuronal processes that conduct afferent impulses to the spinal cord, whereas the ventral rootlets conduct efferent impulses from the spinal cord. Respective rootlets from each segment unite to form dorsal and ventral roots :

The dorsal root contains the central processes of sensory neuronal cell bodies that are located in the dorsal root ganglion (DRG) . The DRG is also called a spinal ganglion. The peripheral processes of these neurons are located in the spinal nerve, its rami, and their branches. These processes end at or form receptors.

The ventral root contains motor fibers. Their neuronal cell bodies are found in the gray matter of the spinal cord: ventral horn if the axons innervate skeletal muscle; lateral horn if the axons supply smooth muscle, cardiac muscle, or glands.

Somatic components of a spinal nerve.

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Chapter 21:  Pathology of the Nervous System

Diane Armao; Thomas Bouldin

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Introduction: the central nervous system, cns histology and common cellular responses to injury.

• CEREBROVASCULAR DISEASE
• BRAIN TUMORS
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• NEURODEGENERATIVE DISEASES
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The central nervous system (CNS) comprises the brain and spinal cord and is the most complex organ system in the human body. The CNS differs from other organ systems in the variety of functions that it provides and in the localization of these functions to specialized areas of the CNS. The localization of specialized functions means that a relatively small, focal lesion in the CNS can produce a profound deficit, for example, loss of speech. This localization also results in the various populations of neurons within the CNS having unique capabilities and also unique vulnerabilities to disease. For example, Parkinson disease (PD) preferentially affects the neurons of the substantia nigra in the brain stem, while Alzheimer disease (AD) preferentially affects the neurons of the cerebral cortex.

Neurons ( Figure 21-1 ) are the principal cell type within the nervous system. Acute neuronal injury is most often due to ischemia, but there are many other causes, including trauma, infections, toxic/metabolic diseases, and genetic diseases. Neurons undergoing acute cell death often show red (eosinophilic) cytoplasm and pyknotic nuclei histologically and are referred to as red neurons ( Figure 21-2 ). Neurons may also undergo programmed cell death (apoptosis). Central chromatolysis refers to the changes that occur in the neuronal cell body (usually a lower motor neuron) when its axon is injured (axonal reaction). This axonal reaction is characterized by enlargement of the neuronal cell body, displacement of the neuron's nucleus to the periphery of the cell body, and disappearance of the more centrally located Nissl bodies (stacks of rough endoplasmic reticulum). The more peripherally located Nissl bodies remain, hence the term central chromatolysis.

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• J Undergrad Neurosci Educ
• v.18(1); Fall 2019

The Mysterious Case of Patient X: A Case Study for Neuroscience Students

The Mysterious Case of Patient X is adapted from an actual clinical case of a famous American writer whose symptoms initially presented as Parkinson’s disease. His complex medical history challenges students to investigate alternative diagnoses. Students confront the complexity of biomedical systems from the molecular and cellular processes that underlie neuronal degeneration to the organization and integration of brain regions that control the symptoms of disease.

The case is written for upper-level undergraduate or beginning graduate students in biology or neuroscience but could be adapted for introductory neuroscience courses.

BACKGROUND AND CONTEXT

The American Association for the Advancement of Science report, Vision and Change In Undergraduate Biology Education: A Call to Action ( Brewer & Smith, 2011 ), provides a foundation of core competencies that all students in biological sciences, including neuroscience, should develop through their undergraduate education. These include the ability to apply the process of science, i.e., constructing new knowledge by formulating hypotheses and testing a hypothesis with observations and data. Also included are development of effective communication skills, within and beyond the discipline, and the ability to relate key concepts to society. Case studies provide an excellent tool for building these skills and have been demonstrated to increase student engagement, motivation and self-confidence ( White et al., 2009 ; Yadav et al., 2007 ).

A case study tells a story. The Mysterious Case of Patient X is the real-world story of one of America’s greatest storytellers. Eugene O’Neill is the only American-born playwright to be awarded the Nobel prize in Literature (“ All Nobel Prizes in Literature,” 2019 ) in addition to four Pulitzer Prizes for Drama. His most famous play, “Long Day’s Journey into Night,” is a semi-autobiographical drama that addresses addiction, alcoholism and the impact of these disorders on family dynamics. O’Neill died in 1953 at the age of 65 after suffering for more than a decade with a degenerative neurological disorder diagnosed as Parkinson’s Disease (PD), although the symptoms and progression were atypical. His widow requested an autopsy in order to get a more complete and accurate diagnosis. The results, however, were sealed at her request. Decades later, the surviving grandchildren agreed to the release of the autopsy results. This case study is adapted from the publication of those results in the New England Journal of Medicine ( Price & Richardson, 2000 ).

Parkinson’s Disease is a member of a larger family of parkinsonian syndromes, sometimes called atypical parkinsonian disorders or simply parkinsonism ( Brooks, 2002 ; Williams & Litvan, 2013 ). For this case study, the term Parkinson’s-like disorder (PLD) is used because it less well defined, fostering greater exploration by the students. PD is generally characterized by four key symptoms: tremors, rigidity, bradykinesia, and a shuffling gait. PLDs share many of the motor symptoms associated with PD. However PD is generally distinguished by an asymmetric onset that continues as the disease progresses and, importantly, by a responsiveness to treatment with dopaminergic agonists ( Lew, 2007 ). The latter is a direct consequence of the underlying pathology that characterizes PD: loss of dopaminergic neurons in the substantia nigra and the presence of protein aggregates called Lewy bodies. Today, many PLDs have been characterized and researchers are actively seeking diagnostic tools and therapeutic approaches to these disorders. Although much less was known about the wide range of PLDs in the mid-20 th century, differential diagnosis continues to be a significant challenge. This case study challenges students to confront the complexity of biomedical systems ranging from the molecular and cellular processes that underlie neuronal degeneration to the organization of the brain regions that control the symptoms of disease.

The Mysterious Case of Patient X was developed for an upper-level undergraduate course on Neurobiology of Disease. The pathology report includes family history as well as behavioral, neurological, systems and cellular analysis, providing a broad foundation that can be adapted for many different courses. The original publication has been modified here using the interrupted case method with two scenes and an epilogue. Student materials and implementation notes are available from the corresponding author or from [email protected] .

LEARNING OBJECTIVES

Content objectives.

At the end of the unit, students will be able to:

• describe the progression of PD symptoms and how these relate to brain regions affected by the disease
• describe the criteria for diagnosis of PD
• explain the biological mechanism underlying treatment options for PD including side effects of DA agonists
• list known causes and risk factors for PD and explain the difference
• compare and contrast PD to other related disorders
• apply knowledge of PD to explain why Patient X’s diagnosis is not PD
• describe the significance of the substantia nigra and the anatomical progression of PD pathology
• define α-synuclein and Lewy bodies and explain how they contribute to PD pathology
• describe the proteolytic pathways that are implicated in α-synuclein processing.

Process Objectives

• develop and justify a hypothesis based on available diagnostic criteria
• critically evaluate reliability and accuracy of biomedical information from internet resources
• clearly articulate neuroscientific questions and concepts in a group setting
• demonstrate collaborative problem-solving skills.

CLASSROOM MANAGEMENT OVERVIEW

This case is comprised of two scenes and an epilogue. The unit is taught in four 75-minute class periods but could be easily adapted to less class time. Students should have a basic understanding of neuroscience. Some knowledge of brain structure is helpful, but not required.

• Prior to beginning the case study, students learn the symptoms, criteria for diagnosis, treatments, causes and risk factors associated with PD. This could be included in lecture material prior to beginning the case study. An alternative problem-based learning approach is presented here, in which students consider what they already know, what they don’t know, and then to work in small groups to find the information supported by reliable references. Students research PLDs as a homework assignment.
• The Mysterious Case of Patient X: Part 1 – The Patient presents the patient’s demographic and family history, general medical history, and the neurological progression of the disease. Students consider what information supports the diagnosis of PD and what alternative PLDs should be considered.
• The Mysterious Case of Patient X: Part 2 – Postmortem Findings presents the autopsy results, detailing the anatomical structures of the brain. Again, students consider what information supports the diagnosis of PD and to identify alternative PLDs.
• The Mysterious Case of Patient X: Part 3 – Epilogue concludes the case study presenting the analysis and final conclusions of the pathologists that performed the autopsy. Biographical information about Eugene O’Neill is also provided. The name of the patient is not revealed until the end in order to prevent students from finding the diagnosis through an internet search.

This case study provides a launching point for more advanced discussion of misfolded proteins and protein aggregation. Several genes that are mutated in familial PD are known to function in autophagy and ubiquitin-proteasome pathways. This topic provides a common thread for a wide range of neurological disorders characterized by protein aggregation, including PD, Alzheimer’s disease, Huntington’s disease, Amyotrophic Lateral Sclerosis, and prion diseases ( Ciechanover & Kwon, 2015 ).

CASE EVALUATION

Direct assessment.

The Mysterious Case of Patient X has been taught four semesters. Direct measures of student learning were assessed through classroom participation, assignments and exams. Homework assignments were checked at the beginning of class but not collected until the end, in order to facilitate class participation. Students notes added to the assignment during class were to be clearly indicated.

The exam format was adjusted each year to accommodate modifications in the overall structure of the course. In Spring 2017, the Parkinson’s unit was assessed with a take-home exam that asked students to develop a hypothesis and design an experiment emphasizing material covered beyond the case study. Sample data from the three semesters that were assessed with an in-class exam is shown in Table 1 . These exams served as the primary means of assessing learning outcomes. They included multiple choice, short answer, and, in some cases, an essay question. Students consistently did very well on multiple choice questions. Not surprisingly, students did better in small classes with less than 10 students than in the larger class with 28 students. However, in all cases, students performed well above the proficient level, defined as 80%.

Examples of learning objectives assessed on the unit exam are shown with types of questions and student performance. 2015, n = 9; 2018, n = 7; 2019, n = 28.

Student self-assessment was performed through both a structured survey and an open-ended three-minute reflection. Prior to this unit, the course used two major case studies making it impossible in most cases to determine the relative contribution of The Mysterious Case of Patient X to their responses. The prior cases relied on a problem-based learning approach exemplified by Professor Eric Can ’ t See: A Project-Based Learning Case For Neurobiology Students ( Ogilvie & Ribbens, 2016 ). Nevertheless, some student responses were specific to this case and, since it was taught at the end of the semester, it was likely to bias their responses.

Indirect Assessment

In 2019, students were given both a pre- and post-assessment survey ( Fig 1 ). At the beginning of the semester, students rated their level of experience critically evaluating information in the popular press or internet about neurobiological disorders. On a scale of 1 (no experience) to 5 (extensive experience), the average self-assessment was 3.1 ± 0.98. On the post-assessment survey, students rated how much learning they gained for this element on a scale of 1 (no gain) to 5 (very large gain). The average score was 4.2 ± 0.88, with 100% of the students indicating some level of gain and 78% indicating large or very large gain. In the pre-assessment survey, students rated their level of experience actively participating in class discussion with an average score of 3.8 ± 0.81. In spite of this strong response, students indicated that they had moderate to large gain (3.5 ± 1.13) with 29% of the students indicating very large gain. Using the Likert scale (1 = strongly disagree; 5 = strongly agree), students also rated their level of agreement with the statement: I gained knowledge by learning from my classmates and/or by explaining to them. Notably, 89% of students agreed or strongly agreed with this statement (4.33 ± 0.78).

A . Pre-assessment survey asked students to rate their experience on a scale from no experience (1) to extensive experience (5). B . For the first two items, students were asked on a post-assessment survey to rate how much experience they gained on a scale from no gain (1) to very large gain (5). For the third item, students were asked to rate their agreement with the statement on a scale from strongly disagree (1) to strongly agree (5).

Finally, students were given the following question for a three-minute reflection: “What is the most interesting knowledge you have gained in this class? Why?” Box 1 includes sample responses. Many students commented here and in the university course evaluation that they expected to hate the collaborative learning approach in the class and were surprised to discover how much they loved it, consistent with their responses on the post-assessment survey. Students found The Mysterious Case of Patient X to be “challenging and engaging.” Students also appreciated that this was a real case of a well-known individual. Overall, the self-report data support student fulfillment of the process objectives.

SUMMARY AND FUTURE DIRECTIONS

The Mysterious Case of Patient X is presented as the third and last major case study of the semester. Self-reported data from reflection papers and post-assessment surveys indicate that the approach is successful in student attainment of both content and process learning objectives. This is supported by student performance on exams demonstrating that content objectives were successfully met.

This case study can be adapted in several ways. It can be shortened by introducing basic information on Parkinson’s disease in a lecture format rather than having students research this information in small groups. Assignments may be done individually as homework rather than as groups in class. Having the instructor present more of the background information, would enable the case study to be adapted for introductory level neuroscience courses, where students can appreciate the complexity of the nervous system at the gross level, without necessarily delving into the molecular and cellular systems, that may be more appropriate for an advanced course. Future plans are to add discussion of primary literature that focuses on the biological mechanisms underlying Parkinson’s disease. The Journal Case Study format ( Prud’homme-Généreux, 2016 ) provides an excellent tool for this addition.

Sample student comments.

The author thanks Ken Long for the initial concept, Elena Bray-Speth for valuable discussion on pedagogical approaches and members of the Neuroscience Case Network for their helpful comments and feedback. The Neuroscience Case Network is supported by an NSF RCN-UBE grant #1624104.

• All Nobel Prizes in Literature. 2019. Available at https://www.nobelprize.org/prizes/lists/all-nobel-prizes-in-literature .
• Brewer CA, Smith D. Vision and change in undergraduate biology education: A call to action. Washington, DC: American Association for the Advancement of Science; 2011. [ Google Scholar ]
• Brooks DJ. Diagnosis and management of atypical parkinsonian syndromes. J Neurol Neurosurg Psychiatry. 2002; 72 :I10–I16. Available at https://jnnp.bmj.com/content/72/suppl_1/i10.full . [ PMC free article ] [ PubMed ] [ Google Scholar ]
• Ciechanover A, Kwon YT. Degradation of misfolded proteins in neurodegenerative diseases: therapeutic targets and strategies. Exp Mol Med. 2015; 47 :e147. doi: 10.1038/emm.2014.117. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Lew M. Overview of Parkinson’s disease. Pharmacotherapy. 2007; 27 (12 Pt 2):155S–160S. doi: 10.1592/phco.27.12part2.155S. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Ogilvie JM, Ribbens E. Professor Eric Can’t See: A Project-Based Learning Case for Neurobiology Students. J Undergrad Neurosci Educ. 2016; 15 (1):C4–C6. [ PMC free article ] [ PubMed ] [ Google Scholar ]
• Price BH, Richardson EP., Jr The neurologic illness of Eugene O’Neill--a clinicopathological report. N Engl J Med. 2000; 342 (15):1126–1133. doi: 10.1056/NEJM200004133421511. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Prud’homme-Généreux A. Writing a Journal Case Study. Journal of College Science Teaching. 2016; 45 (6):65–70. [ Google Scholar ]
• White TK, Whitaker P, Gonya T, Hein R, Kroening D, Lee K, Lee L, Lukowiak A, Hayes E. The use of interrupted case studies to enhance critical thinking skills in biology. J Microbiol Biol Educ. 2009; 10 (1):25–31. Available at: https://www.asmscience.org/content/journal/jmbe/10.1128/jmbe.v10.96 . [ PMC free article ] [ PubMed ] [ Google Scholar ]
• Williams DR, Litvan I. Parkinsonian syndromes. Continuum (Minneap Minn) 2013; 19 (5 Movement Disorders):1189–1212. doi: 10.1212/01.CON.0000436152.24038.e0. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Yadav A, Lundeberg M, DeSchryver M, Dirkin K, Schiller NA, Maier K, Herreid CF. Teaching Science with Case Studies: A National Survey of Faculty Perceptions of the Benefits and Challenges of Using Cases. Journal of College Science Teaching. 2007; 37 (1):34–38. [ Google Scholar ]

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Neurological Disorders Case Studies

Case study 1 – the man with no memory.

Henry Molaison, known by thousands as “H.M.”, is probably the best known single patient in the history of neuroscience. His severe memory impairment, which resulted from experimental brain surgery to control seizures, was the subject of study for five decades until his death in December 2008. Work with H.M. established fundamental principles about how memory functions are organized in the brain. In this case study, students predict H.M.’s performance in some of Milner’s most famous experiments with H.M.

Download Case Study 1 here .

Case Study 2 — What causes Alzheimer’s Disease?

Axonal transport systems are crucial to maintain neuronal viability and differentiation. Considerable evidence suggests that failure of axonal transport may play a role in the development and progression of neurological diseases such as Alzheimer’s disease. The goal of the research study this lesson focuses on investigates the role of axonal transport in the pathology of Alzheimer’s disease.

Download Case Study 2 here .

Case Study 3 — How do placebos work?

The placebo effect occurs when we perceive that an inactive substance is having the effect of an active substance. In this case study, students analyze real data from an original research paper investigating subjects’ reaction to pain when given a placebo ‘pain reliever’ or a control. Both control and ‘pain reliever’ were actually the same. Students are asked to consider the design of the experiment and then predict outcomes based on stated hypotheses. They then analyze and interpret the actual data and compare to their own predictions.

Download Case Study 3 here .

Case Study 4 — What causes narcolepsy?

In this study, students synthesize information from different studies to arrive at a model to explain the neuronal basis for narcolepsy. In this study the authors actually removed the gene candidate for causing narcolepsy and were able to show that removing the gene caused narcolepsy symptoms to develop in comparison with controls. This evidence is indicative of causation. In a second set of experiments the authors showed that humans with narcolepsy had fewer neurons expressing this gene, further evidence that the gene in question plays a causative role in narcolepsy.

Download Case Study 4 here .

Case Study 5 – What role do cues play in addiction?

In this study, students analyze and interpret data from different studies then synthesize this information to arrive at a model to explain the role that contextual cues play in self-stimulation with alcohol or sugar. In this study the authors trained rats to anticipate a self-reinforcer (alcohol or sugar) and then measured the time frame of the rats’ response and levels of dopamine in the rats’ nucleus accumbens. They were able to show that rats were able to learn to anticipate self-stimulation when presented with a contextual cue and that their locomotion increased during the anticipatory phase. When the self-reinforcer was alcohol, dopamine levels in the nucleus accumbens rose during the anticipatory phase as well as during the consummatory phase showing that the rise is not simply a consequence of self-stimulation. In contrast although rats could learn to self-stimulate for sugar in response to a contextual cue it neither increased locomotion during the anticipatory phase nor increased dopamine levels in the nucleus accumbens during either phase. The results are evidence that a contextual cue can activate the reward pathway in advance of a self-reinforcing stimulus.

Download Case Study 5 here .

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Class 11th Biology - Neural Control and Coordination Case Study Questions and Answers 2022 - 2023

By QB365 on 09 Sep, 2022

QB365 provides a detailed and simple solution for every Possible Case Study Questions in Class 11 Biology Subject - Neural Control and Coordination, CBSE. It will help Students to get more practice questions, Students can Practice these question papers in addition to score best marks.

QB365 - Question Bank Software

Neural control and coordination case study questions with answer key.

11th Standard CBSE

Final Semester - June 2015

The following flow chart gives the steps in the generation and conduction of a nerve impulse along a nerve fibre. Fill in the blanks A, B, C, D, E and F. At resting/polarised state of the neuron, the electrical potential difference is called ______ (A).                                        \(\downarrow\)   When the neuron is stimulated at a point, there is a rapid influx of _____(B) and the outer side becomes ______(C) charged.                                        \(\downarrow\)   The membrane is ______(D) and the potential difference across the membrane, is called _______(E).                                        \(\downarrow\)   The permeability of the membrane to B is very short-lived and the membrane potential A is restored, i.e. membrane is _______(F).

Anatomically, the human ear can be divided into three regions, (i) external ear, (ii) middle ear and (iii) inner ear. The inner ear, also called labyrinth, consists of two parts, (i) the coiled part, cochlea and (ii) the vestibular apparatus (a) Mention the component parts of the vestibular apparatus. (b) Name the specific receptors in the vestibular apparatus. (c) What is the function of vestibular apparatus?

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Neural control and coordination case study questions with answer key answer keys.

A - PNS (Peripheral nervous system) B - Spinal cord C - Somatic nervous system D - Forebrain E - Hindbrain F - Parasympathetic nervous system.

A. Resting potential B. Na C. Negatively D. Depolarised E. Action potential F. Repolarised.

(A) Synaptic vesicles (B) Neurotransmitters  (C) Synaptic cleft (D) Post-synaptic membrane (E) Ion channels (F) Post-synaptic neuron.

A - Receptor (muscle spindle) B - Afferent pathway C - Dorsal root ganglion D - Interneuron E - Motor neuron F - Efferent pathway.

(a) -A-Cornea (b) -G-Fovea (c) -E-Ciliarybody (d) -F -Vitreous chamber (e) -D-Iris (f) -H-Blindspot

(a) Vestibular apparatus consists of three semicircular canals and an otolith organ, consisting of utricle and saccule. (b) Crista and macula. (c) lt is responsible for the maintenance of body balance and posture.

(o) G Reissner's membrane D - Basilar membrane (b) F Scala media (c) E - Organ of Corti (d) B - Tectorial membrane (e) A Scala vestibuli.

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Peripheral Nervous System Patient Case Studies

Nine interactive computer-based cases providing beginner health professionals with drill-and-practice exercises that assess introductory nervous system content acquisition and knowledge. Another version of it is published by MedEdPORTAL (MEP ID# 3159).

Media:  Interactive Patient Cases

Last Update:  12/14/2007

Authors:  Reilly, F., E. Allen, A. Reed, and J. Altemus.

Certification:  HEAL, 2009, ID = 429

Technology:  Browser (Internet Explorer 6.0 or higher, Firefox 2.0 or higher, Safari 3.0 or higher) and Adobe Flash 6.0 or higher.

Copyright:  WVU and Frank Reilly

Contact:   [email protected]

Links:   HSC  |  External

Central Nervous System: Case Study

Welcome to the 21st Century electronic classroom for Advanced Human and Physiology class. You can find additional resources on my science web site Mitchell's Cosmic Adventure. Com. While case studies cannot provide specific guidance for the management of successive patients, they are a record of clinical interactions. You will need to locate the Google Document file on my website. Here will need to read the case study: Spinal Cord Injury, the patient is Thomas (Tommy) Potter. It is under the Nervous System TAB and then select Central Nervous System - Patient Medical History! Read more This test has a T. E. M. (Test Exam Mode) setting that doesn't reveal the answer during the test period. A report and certificate will be printed for each attempt. Each attempt will randomly generate a new set of 20 questions and answers. This is a method to cover all the material and increase your testing ability. Good Luck on this case study and your studies in Human Anatomy & Physiology!

What activity was Thomas (Tommy) Potter, a 20-year old college student performing to send him to emergency Trauma Center for treatment?

Riding a bicycle

Rock climbing

Jogging on campus

Playing tennis

Painting the ceiling of his campus apartment

Rate this question:

After you gathered initial information from this patient concerning his activities on campus.  Please check all to which apply to Mr. Potter.  

Which one of the following explanations best describes the changes in Thomas's vital signs?

Lying on his back during transport

The level and extent of injury

Anxiety related to the injury

Lack of Mobility during transport

Tommy Potter is a 20-year old college student, who was rock climbing and fell _____ meters to the ground. Please round to one tenth of a decimal.

How tall is tommy potter in ______centimeters  please round to one tenth of a centimeter., what was thomas potter's skin condition in the emergency room  please check all which applies to this patient..

Paramedics applied a cervical collar at the scene of the accident, placed him on a backboard and immobilized his head. Mr. Potter asked a paramedic why he could feel just a little sensation in some parts of his arms and legs. The paramedic's response would be based on the understanding that:   (HINT: this is a multiple answer question.)

A concussion is causing these transient signs

The autonomic nervous center in the cerebellum was injured

C5 and C6 injury would be consistent with these sensations

Brain pathways are too complex to respond to his question

Damage to this patent's cervical region is in question

Damage to the spinal cord will affect the function of the nervous from the point of injury upward.

Due to the nature of tommys injuries, all of the following central nervous system functions will be affected except :.

Control of posture

Conduction route to the brain

Reflex activity for the spine

Conduction route from the brain

Control of posture is a cerebellar activity, not a spinal cord function.

Dr. john babinski was checking tommy's vital signs and noticed a drop in his blood pressure. what is causing this condition at the time of the emergency.

patient has suffered damage to his spinal cord

Patient has no sensory detection in his arms

Patient has no motor movement in his arms

Patient has no sensory detection in his legs

Patient has no motor movement in his legs

___ ___ is a combination of areflexia/hyporeflexia and autonomic dysfunction that accompanies spinal cord injury .

What is spinal shock phase 1?

0 - 1 day: areflexia/Hyporeflexia

1 - 3 days: Initial reflex return

1 - 4 weeks: Hyperreflexia (initial)

1 - 12 weeks: Hyperreflexia, Spasticity

What is spinal shock phase 2?

What is spinal shock phase 3?

What is spinal shock phase 4?

What phrases of spinal shock shows strong reflexes usually produced with minimal stimulation. Motor neurons begin sprouting and attempting to re-establish synapses?

Phase 1 - 0 - 1 day: areflexia/Hyporeflexia

Phase 2 - 1 - 3 days: Initial reflex return

Phase 3 - 1 - 4 weeks: Hyperreflexia (initial)

Phase 4 - 1 - 12 weeks: Hyperreflexia, Spasticity

What does S.C.I. stand for as it relates to spinal shock?

Standard Control Instructions

Spinal Cord Injury

Spinal Cord Instructions

Spinal Control Instructions

Spinal Cord Innervation

What is the cause of Thomas Potter's respiratory rate at 24 (very shallow breathing)?

Injury to C3

Injury to C4

Injury to C5

Injury to T1

Injury to C4 and C5

Which cervical vertebrae was damaged in the patient's rock climbing injury? Taking all of the physical examination findings suggest that there was incomplete, diffuse, bilateral damage to the spinal cord at about the ___ segment.

Due to damage of the c5 vertebrae and the respiration rate of this patient. what condition is causing his blood ph to 7.25.

Thomas is hypoventilating resulting in respiratory acidosis.

Thomas is hyperventilating resulting in respiratory acidosis.

Thomas is hyporeflexia resulting in respiratory acidosis.

Thomas is not breathing on his own resulting in respiratory acidosis.

At what blood pH would Thomas have died?

The micturition reflex may return as Mr Potter's spinal shock resolves, since this reflex arc involves non-damaged segments of the spinal cord (S2 to S4).

What is the halo traction brace called?

Halo Orthosis

Cervical Halo Brace

Thoracic Halo Brace

Lumbar Halo Orthosis

Cervical Orthosis

Tommy Potter will wear his halo orthosis due to severe damage to the C5 vertebrae for ___ weeks. (Hint: please enter a number from 5 to 24 .)

How many rock climbing members are part of Thomas's team including himself?

___ / ___ is the medical term used when a person has a spinal cord injury above the first thoracic vertebra. Paralysis affects the cervical spinal nerves (C1-C8) resulting in paralysis in varying degrees in all four limbs.

Tetraplegia

Quadriplegia

Cauda Equina Syndrome

___ / ___ is the medical term used when the level of spinal cord injury occurs below the first thoracic spinal nerve root (T1-S5). The degree at which the person is paralysed can vary from the impairment of leg movement, to complete paralysis of the legs and abdomen up to the nipple line. Paraplegics have full use of their arms and hands.

___ / ___  is the mass of nerves which fan out of the spinal cord at just below the first and second Lumbar region of the spinal cord, an area known as the conus medullaris. The spinal cord ends at L1 and L2 at which point a bundle of nerves travel downwards within the lumbar and sacral vertebrae.

When Cauda Equina Syndrome,  Injury to these nerves will cause partial or complete loss of movement and sensation of ___, ___, ___, and ___.

Urinary Bladder

Sexual Organs

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9.9: Case Study Conclusion- Memory and Chapter Summary

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• Suzanne Wakim & Mandeep Grewal
• Butte College

Case Study Conclusion: Fading Memory

Figure \(\PageIndex{1}\) illustrates some of the molecular and cellular changes that occur in Alzheimer’s disease (AD), which Rosa was diagnosed with at the beginning of this chapter, after experiencing memory problems and other changes in her cognitive functioning, mood, and personality. These abnormal changes in the brain include the development of amyloid plaques between brain cells and neurofibrillary tangles inside of neurons. These hallmark characteristics of AD are associated with the loss of synapses between neurons, and ultimately the death of neurons.

After reading this chapter, you should have a good appreciation for the importance of keeping neurons alive and communicating with each other at synapses. The nervous system coordinates all of the body’s voluntary and involuntary activities. It interprets information from the outside world through sensory systems and makes appropriate responses through the motor system, through communication between the PNS and CNS. The brain directs the rest of the nervous system and controls everything from basic vital functions such as heart rate and breathing to high-level functions such as problem-solving and abstract thought. The nervous system is able to perform these important functions by generating action potentials in neurons in response to stimulation and sending messages between cells at synapses, typically using chemical neurotransmitter molecules. When neurons are not functioning properly, lose their synapses, or die, they cannot carry out the signaling that is essential for the proper functioning of the nervous system.

AD is a progressive neurodegenerative disease, meaning that the damage to the brain becomes more extensive as time goes on. Figure \(\PageIndex{2}\) illustrates how the damage progresses from before AD is diagnosed (preclinical AD), to mild and moderate AD, and finally to severe AD.

You can see that the damage starts in a relatively small location towards the bottom of the brain. One of the earliest brain areas to be affected by AD is the hippocampus. The hippocampus is important for learning and memory. This explains why many of Rosa’s symptoms of mild AD involve deficits in memory, such as trouble remembering where she placed objects, recent conversations, and appointments.

As AD progresses, more of the brain is affected, including areas involved in emotional regulation, social behavior, planning, language, spatial navigation, and higher-level thought. Rosa is beginning to show signs of problems in these areas, including irritability, lashing out at family members, getting lost in her neighborhood, problems finding the right words, putting objects in unusual locations, and difficulty in managing her finances. You can see that as AD progresses, damage spreads further across the cerebrum, which you now know controls conscious functions such as reasoning, language, and interpretation of sensory stimuli. You can also see how the frontal lobe, which controls executive functions such as planning, self-control, and abstract thought, becomes increasingly damaged.

Increasing damage to the brain causes corresponding deficits in functioning. In moderate AD, patients have increased memory, language, and cognitive deficits compared to mild AD. They may not recognize their own family members, and may wander and get lost, engage in inappropriate behaviors, become easily agitated, and have trouble carrying out daily activities such as dressing. In severe AD, much of the brain is affected. Patients usually cannot recognize family members or communicate and are fully dependent on others for their care. They begin to lose the ability to control their basic functions, such as bladder and bowel control and proper swallowing. Eventually, AD causes death, usually as a result of this loss of basic functions.

For now, Rosa only has mild AD is still able to function relatively well with care from her family. The medication her doctor gave her has helped improve some of her symptoms. It is a cholinesterase inhibitor, which blocks an enzyme that normally degrades the neurotransmitter acetylcholine. With more of the neurotransmitter available, more of it can bind to neurotransmitter receptors on postsynaptic cells. Therefore, this drug acts as an agonist for acetylcholine, which enhances communication between neurons in Rosa’s brain. This increase in neuronal communication can help restore some of the functions lost in early Alzheimer’s disease and may slow the progression of symptoms.

But medication such as this is only a short-term measure and does not halt the progression of the underlying disease. Ideally, the damaged or dead neurons would be replaced by new, functioning neurons. Why does this not happen automatically in the body? As you have learned, neurogenesis is very limited in adult humans, so once neurons in the brain die, they are not normally replaced to any significant extent. However, scientists are studying the ways in which neurogenesis might be able to be increased in cases of disease or injury to the brain. Also, they are investigating the possibility of using stem cell transplants to replace damaged or dead neurons with new neurons. But this research is in very early stages and is not currently a treatment for AD.

One promising area of research is in the development of methods to allow earlier detection and treatment of AD, given that the changes in the brain may actually start 10 to 20 years before the diagnosis of AD. For example, a radiolabeled chemical called Pittsburgh Compound B (PiB) binds to amyloid plaques in the brain and in the future may be used in conjunction with brain imaging techniques to detect early signs of AD. Scientists are also looking for biomarkers in bodily fluids such as blood and cerebrospinal fluid that might indicate the presence of AD before symptoms appear. Finally, researchers are also investigating possible early and subtle symptoms, such as changes in how people move or a loss of smell, to see whether they can be used to identify people who will go on to develop AD. This research is in the early stages, but the hope is that patients can be identified earlier to provide earlier and possibly more effective treatment and to allow families more time to plan.

Scientists are also still trying to fully understand the causes of AD, which affects more than 5 million Americans. Some genetic mutations have been identified that play a role, but environmental factors also appear to be important. With more research into the causes and mechanisms of AD, hopefully, a cure can be found, and people like Rosa can live a longer and better life.

Chapter Summary

In this chapter, you learned about the human nervous system. Specifically, you learned that:

• The nervous system is the organ system that coordinates all of the body’s voluntary and involuntary actions by transmitting signals to and from different parts of the body. It has two major divisions, the central nervous system (CNS) and the peripheral nervous system (PNS).
• The CNS includes the brain and spinal cord.
• The PNS consists mainly of nerves that connect the CNS with the rest of the body. It has two major divisions: the somatic nervous system and the autonomic nervous system. The somatic system controls activities that are under voluntary control. The autonomic system controls activities that are involuntary.
• The autonomic nervous system is further divided into the sympathetic division, which controls the fight-or-flight response; the parasympathetic division, which controls most routine involuntary responses; and the enteric division, which provides local control for digestive processes.
• Signals sent by the nervous system are electrical signals called nerve impulses. They are transmitted by special, electrically excitable cells called neurons, which are one of two major types of cells in the nervous system.
• Glial cells are the other major type of nervous system cells. There are many types of glial cells, and they have many specific functions. In general, glial cells function to support, protect, and nourish neurons.
• The main parts of a neuron include the cell body, dendrites, and axon. The cell body contains the nucleus. Dendrites receive nerve impulses from other cells, and the axon transmits nerve impulses to other cells at axon terminals. A synapse is a complex membrane junction at the end of an axon terminal that transmits signals to another cell.
• Axons are often wrapped in an electrically-insulating myelin sheath, which is produced by glial cells. Electrical impulses called action potentials occur at gaps in the myelin sheath, called nodes of Ranvier, which speeds the conduction of nerve impulses down the axon.
• Neurogenesis, or the formation of new neurons by cell division, may occur in a mature human brain but only to a limited extent.
• The nervous tissue in the brain and spinal cord consists of gray matter, which contains mainly the cell bodies of neurons; and white matter, which contains mainly myelinated axons of neurons. Nerves of the peripheral nervous system consist of long bundles of myelinated axons that extend throughout the body.
• There are hundreds of types of neurons in the human nervous system, but many can be classified on the basis of the direction in which they carry nerve impulses. Sensory neurons carry nerve impulses away from the body and toward the central nervous system, motor neurons carry them away from the central nervous system and toward the body, and interneurons often carry them between sensory and motor neurons.
• A nerve impulse is an electrical phenomenon that occurs because of a difference in electrical charge across the plasma membrane of a neuron.
• The sodium-potassium pump maintains an electrical gradient across the plasma membrane of a neuron when it is not actively transmitting a nerve impulse. This gradient is called the resting potential of the neuron.
• An action potential is a sudden reversal of the electrical gradient across the plasma membrane of a resting neuron. It begins when the neuron receives a chemical signal from another cell or some other type of stimulus. The action potential travels rapidly down the neuron’s axon as an electric current.
• A nerve impulse is transmitted to another cell at either an electrical or a chemical synapse. At a chemical synapse, neurotransmitter chemicals are released from the presynaptic cell into the synaptic cleft between cells. The chemicals travel across the cleft to the postsynaptic cell and bind to receptors embedded in its membrane.
• There are many different types of neurotransmitters. Their effects on the postsynaptic cell generally depend on the type of receptor they bind to. The effects may be excitatory, inhibitory, or modulatory in more complex ways. Both physical and mental disorders may occur if there are problems with neurotransmitters or their receptors.
• The CNS includes the brain and spinal cord. It is physically protected by bones, meninges, and cerebrospinal fluid. It is chemically protected by the blood-brain barrier.
• The brain is the control center of the nervous system and of the entire organism. The brain uses a relatively large proportion of the body’s energy, primarily in the form of glucose.
• The brain is divided into three major parts, each with different functions: brain stem, cerebellum, and cerebrum. The cerebrum is further divided into left and right hemispheres. Each hemisphere has four lobes: frontal, parietal, temporal, and occipital. Each lobe is associated with specific senses or other functions.
• The cerebrum has a thin outer layer called the cerebral cortex. Its many folds give it a large surface area. This is where most information processing takes place.
• Inner structures of the brain include the hypothalamus, which controls the endocrine system via the pituitary gland; and the thalamus, which has several involuntary functions.
• The spinal cord is a tubular bundle of nervous tissues that extends from the head down the middle of the back to the pelvis. It functions mainly to connect the brain with the PNS. It also controls certain rapid responses called reflexes without input from the brain.
• A spinal cord injury may lead to paralysis (loss of sensation and movement) of the body below the level of the injury because nerve impulses can no longer travel up and down the spinal cord beyond that point.
• The PNS consists of all the nervous tissue that lies outside of the CNS. Its main function is to connect the CNS to the rest of the organism.
• The tissues that make up the PNS are nerves and ganglia. Ganglia act as relay points for messages that are transmitted through nerves. Nerves are classified as sensory, motor, or a mix of the two.
• The PNS is not as well protected physically or chemically as the CNS, so it is more prone to injury and disease. PNS problems include injury from diabetes, shingles, and heavy metal poisoning. Two disorders of the PNS are Guillain-Barre syndrome and Charcot-Marie-Tooth disease.
• The human body has two major types of senses, special senses, and general senses. Special senses have specialized sense organs and include vision (eyes), hearing (ears), balance (ears), taste (tongue), and smell (nasal passages). General senses are all associated with touch and lack special sense organs. Touch receptors are found throughout the body but particularly in the skin.
• All senses depend on sensory receptor cells to detect sensory stimuli and transform them into nerve impulses. Types of sensory receptors include mechanoreceptors (mechanical forces), thermoreceptors (temperature), nociceptors (pain), photoreceptors (light), and chemoreceptors (chemicals).
• Touch includes the ability to sense pressure, vibration, temperature, pain, and other tactile stimuli. The skin includes several different types of touch receptor cells.
• Vision is the ability to sense light and see. The eye is the special sensory organ that collects and focuses light, forms images, and changes them to nerve impulses. Optic nerves send information from the eyes to the brain, which processes the visual information and “tells” us what we are seeing.
• Common vision problems include myopia (nearsightedness), hyperopia (farsightedness), and presbyopia (age-related decline in close vision).
• Hearing is the ability to sense sound waves, and the ear is the organ that senses sound. It changes sound waves to vibrations that trigger nerve impulses, which travel to the brain through the auditory nerve. The brain processes the information and “tells” us what we are hearing.
• The ear is also the organ that is responsible for the sense of balance, which is the ability to sense and maintain an appropriate body position. The ears send impulses on head position to the brain, which sends messages to skeletal muscle via the peripheral nervous system. The muscles respond by contracting to maintain balance.
• Taste and smell are both abilities to sense chemicals. Taste receptors in taste buds on the tongue sense chemicals in food and olfactory receptors in the nasal passages sense chemicals in the air. The sense of smell contributes significantly to the sense of taste.
• Psychoactive drugs are substances that change the function of the brain and result in alterations of mood, thinking, perception, and/or behavior. They include prescription medications such as opioid painkillers, legal substances such as nicotine and alcohol, and illegal drugs such as LSD and heroin.
• Psychoactive drugs are divided into different classes according to their pharmacological effects. They include stimulants, depressants, anxiolytics, euphoriants, hallucinogens, and empathogens. Many psychoactive drugs have multiple effects so they may be placed in more than one class.
• Psychoactive drugs generally produce their effects by affecting brain chemistry. Generally, they act either as agonists, which enhance the activity of particular neurotransmitters; or as antagonists, which decrease the activity of particular neurotransmitters.
• Psychoactive drugs are used for various purposes, including medical, ritual, and recreational purposes.
• Misuse of psychoactive drugs may lead to addiction, which is the compulsive use of a drug despite negative consequences. Sustained use of an addictive drug may produce physical or psychological dependence on the drug. Rehabilitation typically involves psychotherapy and sometimes the temporary use of other psychoactive drugs.

In addition to the nervous system, there is another system of the body that is important for coordinating and regulating many different functions – the endocrine system. You will learn about the endocrine system in the next chapter.

Chapter Summary Review

• Which part of the brain is neuron A located in — the cerebellum, cerebrum, or brain stem? Explain how you know.
• The cell body of neuron A is located in a lobe of the brain that is involved in abstract thought, problem-solving and planning. Which lobe is this?
• Part of neuron A travels all the way down to the spinal cord to meet neuron B. Which part of neuron A travels to the spinal cord?
• Neuron A forms a chemical synapse with neuron B in the spinal cord. How is the signal from neuron A transmitted to neuron B?
• Is neuron A in the central nervous system (CNS) or peripheral nervous system (PNS)?
• The axon of neuron B travels in a nerve to a skeletal muscle cell. Is the nerve part of the CNS or PNS? Is this an afferent nerve or an efferent nerve?
• What part of the PNS is involved in this pathway — the autonomic nervous system or the somatic nervous system? Explain your answer.
• What are the differences between a neurotransmitter receptor and a sensory receptor?
• The axon terminal
• The nodes of Ranvier
• The dendrites
• The cell body
• True or False. Glial cells produce action potentials.
• True or False. The spinal cord consists of white matter only.
• True or False. Axons may be more than a meter long in adult humans.
• If a person has a stroke and as a result has trouble using language correctly, which hemisphere of their brain was most likely damaged? Explain your answer.
• head region
• trunk and leg regions
• Define what an electrical gradient is, in the context of a cell.
• What is responsible for maintaining the electrical gradient that results in the resting potential?
• Compare and contrast the resting potential and the action potential.
• Where along a myelinated axon does the action potential occur? Why does it happen here?
• What does it mean that the action potential is “all-or-none?”
• The neurotransmitter itself
• The specific receptor for the neurotransmitter on the postsynaptic cell
• The number of synaptic vesicles in the axon terminal
• Whether it is in a sensory neuron or a motor neuron
• Compare and contrast Schwann cells and oligodendrocytes.
• True or False. The cerebellum makes up most of the brain and is divided into four lobes.
• True or False. The hypothalamus is part of the brain.
• Mechanoreceptors
• Nociceptors
• Photoreceptors
• Chemoreceptors
• For the senses of smell and hearing, name their respective sensory receptor cells, what type of receptor cells they are, and what stimuli they detect.
• True or False. Sensory information such as smell, taste, and sound, are carried to the CNS by cranial nerves.
• True or False. The parasympathetic nervous system is a division of the central nervous system.

Attributions

• Characteristics of AD by National Institute on Aging, National Institutes of Health; public domain via Wikimedia Commons
• Alzheimer’s Disease, Spreads through the Brain by National Institute on Aging, National Institutes of Health; public domain via Flickr.com
• Text adapted from Human Biology by CK-12 licensed CC BY-NC 3.0