Download chapter 9: nervous system

CHAPTER 9:
NERVOUS SYSTEM
9.1 Introduction
Learning Outcome 1: Distinguish between the two types of cells that comprise nervous
tissue.
and
Learning Outcome 2: Name the two major groups of nervous system organs.
1. Lecture Suggestions and Guidelines
a. Describe the structures that provide sensory, integrative, and motor functions.
b. Discuss the similarities and differences between the central and peripheral nervous systems.
c. Identify the cell body, axon, and dendrites of a neuron.
2. Application Question(s)
a. Ask students to identify microscopic structures of the nervous system.
Answer: Provide students with prepared slides that exhibit dendrites, the cell body, an axon, and
neuroglial cells.
3. Critical Thinking Issue(s)
a. Compare and contrast various types of glial cells, based on structure and function.
Answer: Responses may include an analysis of microglial cells, oligodendrocytes, astrocytes, and
ependymal cells.
9.2 General Functions of the Nervous System
Learning Outcome 3: Explain the general functions of the nervous system.
1. Lecture Suggestions and Guidelines
a. Give an overview of the nervous system.
b. Describe how the nervous system interacts with other systems of the human body.
c. Lecture on the general functions of the nervous system, including the sensory function, integrative
function, and motor functions.
2. Application Question(s)
a. Ask students to develop an organizational chart that illustrates the interrelationships among the
major divisions and subdivisions of the nervous system.
Answer: The chart should include the central nervous system, peripheral nervous system, sensory
division, motor division, autonomic nervous system, somatic nervous system, sympathetic nervous
system, and parasympathetic nervous system.
3. Critical Thinking Issue(s)
a. Divide the class into small groups and ask each group to define brain death. Discuss their
viewpoints.
Answer: Consider the moral, ethical, legal, medical, and financial implications of the definition.
Learning Outcome 4: State the functions of neuroglial cells in the central nervous system.
and
Learning Outcome 5: Distinguish among the types of neuroglial cells in the central nervous
system.
and
Learning Outcome 6: Describe the Schwann cells of the peripheral nervous system.
1. Lecture Suggestions and Guidelines
a. Describe the functions of neuroglial cells, including filling spaces, providing structural frameworks,
producing myelin, and carrying on phagocytosis.
b. Discuss the specific role of each type of glial cell.
c. Identify the function of Schwann cells.
2. Application Question(s)
a. Ask students to devise a chart depicting various functions of each type of neuroglial cell.
Answer: The students’ charts will include a comparison of microglial cells, oligodendrocytes,
astrocytes, and ependymal cells.
3. Critical Thinking Issue(s)
a. Ask students to research a disease that may result from malfunctioning accessory cells in the
nervous system.
Answer: An example of such a disease is multiple sclerosis, which affects the myelin sheath formed
by Schwann cells.
9.4 Neurons
Learning Outcome 7: Describe the general structure of a neuron.
1. Lecture Suggestions and Guidelines
a. Give an overview of neuron structure.
b. Introduce the major components of a neuron, including the cell body, neurofibrils, Nissl bodies,
dendrites, axons, Schwann cells, myelin sheath, neurilemma, and nodes of Ranvier.
c. Distinguish between gray matter and white matter.
2. Application Question(s)
a. Provide students with an unlabeled diagram of a neuron and ask them to label it.
Answer: The labeled diagram should contain the cell body, dendrite, axon, nucleus, Nissl body,
neurilemma, node of Ranvier, Schwann cell, myelin sheath, axonal terminal, synapse, and neurofibril.
3. Critical Thinking Issue(s)
a. What do we call the portion of the neuron process that connects dendrites to the axon?
Answer: In unipolar sensory neurons, the portion of the neuron process that connects dendrites to the
axon conveys properties of both. Therefore, that portion from dendrites to cell body, is called a
peripheral process. The second portion, from the cell body to the CNS, is referred to as the central
process.
Learning Outcome 8: Explain how differences in structure and function are used to classify
neurons.
1. Lecture Suggestions and Guidelines
a. Give an overview of the classification of neurons based upon structural differences.
b. Discuss bipolar neurons, unipolar neurons, and multipolar neurons.
c. Give an overview of the classification of neurons based upon functional differences.
d. Discuss sensory neurons, interneurons, and motor neurons.
e. Describe an ischemic cell change.
2. Application Question(s)
a. Distinguish among the major types of sensory receptors.
Answer: Students should be able to distinguish among Meissner’s corpuscle, Ruffini’s corpuscle,
Pacinian corpuscle, Golgi tendon organ, and Krause’s end bulb.
3. Critical Thinking Issue(s)
a. What are the major concerns when treating a third-degree burn patient?
Answer: Concerns may include infection, suffocation due to burned air passageways, scar tissue
formation, inhibited regeneration of damaged tissue.
9.5 The Synapse
Learning Outcome 9: Explain how information passes from one neuron to another.
and
9.6 Cell Membrane Potential
Learning Outcome 10: Explain how a membrane becomes polarized.
and
9.7 Nerve Impulses
Learning Outcome 11: Describe the events that lead to the conduction of a nerve impulse.
1. Lecture Suggestions and Guidelines
a. Describe how polarization is due to an unequal distribution of positive and negative ions between
sides of a cell membrane.
b. Discuss the concept of the opening and closing of channels.
c. Explain the development of the resting membrane potential.
d. Distinguish between depolarization and repolarization.
e. List the major events leading to the conduction of a nerve impulse.
f. Describe the all-or-none response.
2. Application Question(s)
a. Are neurons likely to be a site for tumorigenesis in adults?
Answer: Supporting cells, such as neuroglia and Schwann cells, all of which are mitotically active, are
more likely sites for the development of a tumor. Fully mature neurons, as well as some precursor
cells, are not capable of mitosis.
3. Critical Thinking Issue(s)
a. Explain what happens when your arm “falls asleep” after awkwardly lying on it for an extended
period
of time.
Answer: The pressure exerted on your arm by your body weight has a decrease in supply of oxygen
and nutrients to the neurons. When the pressure is alleviated, you feel a tingling in your arm due to the
return of nerve impulse transmission.
9.8 Synaptic Transmission
Learning Outcome 12: Identify the changes in membrane potential associated with
excitatory and inhibitory neurotransmitters.
and
9.9 Impulse Processing
Learning Outcome 13: Describe the general ways in which the nervous system processes
information.
1. Lecture Suggestions and Guidelines
a. Introduce the term synapse.
b. Describe a synaptic transmission, including excitatory and inhibitory actions.
c. Discuss the role of neurotransmitters.
d. Describe factors affecting synaptic transmission.
e. Introduce the terms neuronal pool, facilitation, convergence, and divergence.
2. Application Question(s)
a. Ask students to describe, in order, eight key events leading to the conduction of a nerve impulse.
Answer: The steps include resting potential, threshold stimulus received, sodium channels open,
sodium ion diffusion, potassium channels open, potassium ion diffusion, stimulation of adjacent
portions, and a wave of action potentials.
3. Critical Thinking Issue(s)
a. Discuss factors that may influence the conduction of a nerve impulse.
Answer: Factors may include calcium deficiency, increases/decreases in extracellular potassium,
sedatives, pressure, cold, and anesthetics.
9.10 Types of Nerves
Learning Outcome 14: Describe how nerve fibers in peripheral nerves are classified.
1. Lecture Suggestions and Guidelines
a. Give an overview of the different types of nerves.
b. Reiterate the definition of a nerve.
c. Give examples of sensory nerves, motor nerves, and mixed nerves.
2. Application Question(s)
a. For each pair of the cranial nerves, what simple, but effective, clinical test could be used to insure
normal function?
Answer: Example: To test cranial nerve pair I, the patient could be asked to identify certain odors,
such as ammonia, oranges, or vanilla. To test cranial nerve pair VIII, the patient would respond to a
tuning fork, etc.
3. Critical Thinking Issue(s)
a. Compare and contrast the somatic and autonomic nervous systems.
Answer: Responses should include a discussion of effector organs, types of neurotransmitters, and
construction of the efferent pathways.
9.11 Nerve Pathways
Learning Outcome 15: Name the parts of a reflex arc, and describe the function of each
part.
1. Lecture Suggestions and Guidelines
a. Describe a nerve pathway.
b. Discuss reflex behaviors and give some examples, for instance, the knee-jerk reflex and withdrawal
reflex.
c. Discuss the parts of a reflex arc.
2. Application Question(s)
a. Ask students to compare the parts of a reflex arc, in terms of description and function.
Answer: Responses should include an analysis of the receptor, sensory neuron, interneuron, motor
neuron,
and effector.
3. Critical Thinking Issue(s)
a. Explain the knee-jerk reflex.
Answer: Striking the patellar region initiates the reflex. The quadriceps femoris stimulates stretch
receptors, which in turn, send a message to the spinal cord, where the sensory axon forms a synapse
with a motor neuron. The impulse travels back to the muscle, causing the leg to extend.
9.12 Meninges
Learning Outcome 16: Describe the coverings of the brain and spinal cord.
1. Lecture Suggestions and Guidelines
a. Introduce the three meningeal layers.
b. Describe the structures and functions of the dura mater, arachnoid mater, and pia mater.
c. Locate the subarachnoid space and discuss its importance.
2. Application Question(s)
a. Ask students to develop a flowchart depicting the location of formation, circulation, and reabsorption
of CSF.
Answer: Begin with a box labeled choroid plexuses of the lateral and third ventricle.
3. Critical Thinking Issue(s)
a. Meningitis is an acute inflammation of the meninges. Which meninges are most likely affected?
Answer: Meningitis most often affects the pia mater and arachnoid mater.
9.13 Spinal Cord
Learning Outcome 17: Describe the structure of the spinal cord and its major functions.
1. Lecture Suggestions and Guidelines
a. Define the spinal cord as a slender nerve column that passes downward from the brain into the
vertebral column.
b. Describe the cervical and lumbar enlargement.
c. Locate the anterior median fissure and posterior median sulcus with the use of wall charts and
models.
d. Describe a nerve tract.
e. Differentiate between an ascending tract and a descending tract.
f. Describe a spinal reflex.
2. Application Question(s)
a. What is spina bifida?
Answer: Spina bifida is a condition in which one or more of the vertebrae fail to fuse, leaving an
opening in the vertebral column. It may not be apparent at birth, but later manifestations include
hydrocephalus, cleft palate, club foot, strabismus, and muscular abnormalities.
3. Critical Thinking Issue(s)
a. What is a subdural hematoma?
Answer: A subdural hematoma occurs when blood collects in the space beneath the dura mater due to
trauma.
This increases pressure between the skull bones and the soft brain tissue.
9.14 Brain
Learning Outcome 18: Name the major parts and functions of the brain.
and
Learning Outcome 19: Distinguish among motor, sensory, and association areas of the
cerebral cortex.
1. Lecture Suggestions and Guidelines
a. Give a general overview of the cerebrum, cerebellum, and brain stem.
b. Lecture on the structure of the cerebrum, including the names and locations of the major lobes.
c. Discuss the functional regions of the cerebral cortex.
d. Describe hemisphere dominance.
e. Lecture on the structure and function of the diencephalon.
f. Describe the major structures of the brain stem.
g. Describe the location and major functions of the cerebellum.
2. Application Question(s)
a. Provide students with an anatomical model of the brain and ask them to identify the major lobes and
describe which functions are associated with each.
Answer: Students should be able to identify major motor, sensory, and association locations on the
model.
3. Critical Thinking Issue(s)
a. Stroke victims are sometimes frustrated during recovery because they know what they want to say,
but cannot vocalize the words. What has most likely happened?
Answer: Responses should include a discussion of Broca’s area.
Learning Outcome 20: Describe the formation and function of cerebrospinal fluid.
1. Lecture Suggestions and Guidelines
a. Describe the role of the choroid plexuses.
b. Define a ventricle and give examples of location, structure, and function in the human brain.
c. Give an overview of the circulatory path of cerebral spinal fluid.
2. Application Question(s)
a. Provide a diagram of the human brain and ask students to trace the flow of cerebrospinal fluid.
Answer: Discussion should begin with the two lateral ventricles and end with the return of CSF to the
blood in the dural sinuses.
3. Critical Thinking Issue(s)
a. Why is it important that a patient remain in a horizontal position following a spinal tap procedure?
Answer: CSF pressure is decreased following this procedure. It is recommended that the patient
remain in a horizontal position for a period of six to twelve hours after the procedure to prevent a
“spinal headache.”
9.15 Peripheral Nervous System
Learning Outcome 21: List the major parts of the peripheral nervous system.
1. Lecture Suggestions and Guidelines
a. Introduce the major subdivisions of the nervous system.
b. Distinguish between the somatic nervous system and the autonomic nervous system.
c. Give an overview of the cranial nerves and spinal nerves, which will be discussed in detail later in
the chapter.
2. Application Question(s)
a. Ask students to investigate the adverse effects of certain drugs on the nervous system. Discuss their
findings in the classroom.
Answer: Suggestions for topics to investigate include barbiturates, benzodiazepines, opiates,
cannabinoids, CNS stimulants, hallucinogens, and anabolic steroids.
3. Critical Thinking Issue(s)
a. Provide students with an anatomical model of the human brain and ask them to identify the
approximate location of the origin of the twelve pairs of cranial nerves.
Answer: Reiterate the concept that the cranial nerves, except for the first pair, arise from the brain
stem.
Learning Outcome 22: Name the cranial nerves, and list their major functions.
1. Lecture Suggestions and Guidelines
a. Discuss the nomenclature of the twelve cranial nerves. Assign each a Roman numeral identification
and a name.
b. Classify each of the cranial nerves by type, i.e., sensory, motor, or mixed.
c. Lecture on the function of each of the twelve cranial nerves.
2. Application Question(s)
a. Ask students to prepare a set of flash cards, each of which has a Roman numeral (from I to XII)
written on the front of the card.
Answer: By revealing the Roman numeral only, ask each student to identify the cranial nerve by
name, type (sensory, motor, or mixed), and function.
3. Critical Thinking Issue(s)
a. Discuss which bodily functions would be affected as each of the twelve cranial nerves becomes
injured.
Answer: Also, give examples of simple tests that could be performed to check the nerve’s function.
Learning Outcome 23: Describe the structure of a spinal nerve.
1. Lecture Suggestions and Guidelines
a. Explain how the anterior branches of the spinal nerves in the thoracic region give rise to intercostal
nerves, and those in other regions combine to form plexuses.
b. Describe the naming of spinal nerves.
c. Discuss various spinal nerve injuries, including whiplash.
d. Describe how a spinal nerve joins the spinal cord.
2. Application Question(s)
a. Ask students to trace which body areas are served by the cervical plexus, brachial plexus, lumbar
plexus, and sacral plexus.
Answer: Direct the students’ responses by offering the following guidelines: cervical plexus contains
the phrenic nerve, brachial plexus contains the axillary, radial, median, musculocutaneous, and ulnar
nerves, lumbar plexus contains the femoral and obturator nerves, and sacral plexus contains the sciatic,
common peroneal, and tibial nerves.
3. Critical Thinking Issue(s)
a. Ask students to determine possible results of damage to the above-mentioned nerves. Use
previously learned body movement nomenclature, such as adduction, extension, plantar flexion, etc.
Answer: Responses will vary.
9.16 Autonomic Nervous System
Learning Outcome 24: Describe the functions of the autonomic nervous system.
1. Lecture Suggestions and Guidelines
a. Give an overview of the autonomic nervous system.
b. Lecture on the general characteristics of the autonomic nervous system, including the sympathetic
and parasympathetic divisions.
c. Describe an autonomic nerve pathway.
2. Application Question(s)
a. Compare the anatomy of the sympathetic and parasympathetic divisions of the autonomic nervous
system.
Answer: Discuss in terms of first and second neurons, collateral ganglion, and postganglionic axons.
3. Critical Thinking Issue(s)
a. Discuss the effects of whiplash.
Answer: Whiplash is an abnormal bending of the neck, commonly caused by rear-end automobile
collisions. It
may cause pain, headaches, and nausea.
Learning Outcome 25: Distinguish between the sympathetic and parasympathetic divisions
of the
autonomic nervous system.
and
Learning Outcome 26: Describe a sympathetic and a parasympathetic nerve pathway.
1. Lecture Suggestions and Guidelines
a. Lecture on the autonomic neurotransmitters.
b. Discuss the control mechanisms of autonomic activity.
c. Compare the effects of neurotransmitter substances on the sympathetic and parasympathetic
divisions. Give examples of these effects on various organs and tissues.
d. Describe the differences between cholinergic and adrenergic responses.
e. Comment on the major differences between a sympathetic nerve pathway and a parasympathetic
nerve pathway.
2. Application Question(s)
a. Discuss the effects of neurotransmitter substances on visceral effectors or actions. Compare the
sympathetic and parasympathetic responses.
Answer: Ask students to compare these effects on the pupil of the eye, heart rate, bronchioles, blood
glucose levels, salivary glands, tear glands, and urinary bladder.
3. Critical Thinking Issue(s)
a. Compare the type of neurotransmitter employed in a sympathetic and parasympathetic response.
Answer: Parasympathetic fibers are cholinergic and secrete acetylcholine. Sympathetic fibers are
adrenergic and secrete norepinephrine.
Related Films
Acupuncture: Anesthesia. 44 min. University of Illinois Film Center.
Acupuncture: An Exploration. 17 min. University of Illinois Film Center.
Advancements in Traumatic Brain Injury. 18 min. Films for the Humanities and Sciences.
Autonomic Nervous System. 17 min. International Film Bureau.
The Autonomic Nervous System. 28 min. Films for the Humanities & Sciences.
Basic Anatomy and Physiology of the Mammal: The Nervous System. 7 min. University of Illinois Film
Center.
The Brain. 28 min. Films for the Humanities & Sciences.
Brain and Behavior. 22 min. University of California Extension Media Center.
Brain Triggers: Biochemicals and Behavior. 45 min. WCB/McGraw-Hill.
Drugs and the Nervous System. 18 min. Churchill Films.
Exploring the Human Brain. 18 min. BFA Educational Media.
Exploring the Human Nervous System. 23 min. Churchill Films.
Fundamentals of the Nervous System. 17 min. Encyclopaedia Britannica Educational Corp.
The Hidden Universe: The Brain. part 1, 23 min.; part 2, 25 min., McGraw-Hill Training Systems.
Human Body: The Brain. 11 min. Encyclopaedia Britannica Educational Corp.
Human Body: Nervous System. 23 min. Coronet Film and Video.
Human Brain. 10 min. University of California Extension Media Center.
The Human Brain. 24 min. Encyclopaedia Britannica Educational Corp.
Marvels of the Brain. 23 min. National Geographic Society.
The Mind of Man. 119 min. University of Illinois Film Center.
Miracle of the Mind. 26 min. McGraw-Hill Training Systems.
Mysteries of the Mind. 59 min. National Geographic Society.
The Nerve Impulse. 21 min. Encyclopaedia Britannica Educational Corp.
Nervous System. 25 min. TV Video Publishing.
Nervous System. 28 min. McGraw-Hill Training Systems.
The Nervous System. 29 min. Insight Media.
The Peripheral Nervous System. 19 min. International Film Bureau.
Physiology: The Nerve Impulse. 22 min. University of Illinois Film Center.
Suggestions for Additional Reading
Barondes, Samuel H. February 25, 1994. Thinking about Prozac. Science, vol. 263. The anti-depressant
drug Prozac alters mood by preventing certain nerve cell receptors from binding a neurotransmitter.
Caldwell, Mark. June 1995. Kernel of fear. Discover. In the brain's amygdala, innocuous stimuli are linked
to painful memories.
Campion, E.W. March 21, 1996. When a mind dies. The New England Journal of Medicine, vol. 334. A
look at dementia.
Chiles III, B.W. and P.R. Cooper. February 22, 1996. Acute spinal injury. The New England Journal of
Medicine. An update on treatments for spinal cord injuries.
Damasio, Hanna, et al. May 20, 1994. The return of Phineas Gage: Clues about the brain from the skull of a
famous patient. Science, vol. 264. A rod blasted through the head of a railroad worker revealed much about
the brain and personality.
Gutin, Jo Ann C. June 1996. A brain that talks. Discover. How are our brains wired for language use?
Helmich, R., de Lane, F., Bloem, B., and Toni, I. August, 2007. Cerebral compensation during motor
imagery in Parkinson’s disease. Neuropsychologica, 45(10), 2201-2215. Retreived June 8, 2007, from
Academic Search Complete database.
Hill, C. Stratton. December 20, 1995. When will adequate pain treatment be the norm? The Journal of the
American Medical Association, vol. 274. Physicians should relieve patients of chronic or cancer- related
pain.
Leshner, A. I. July 11, 1996. Molecular mechanisms of cocaine addiction. The New England Journal of
Medicine, vol. 335. Addiction seen at the molecular level.
Rosenblatt, Roger. August 26, 1996. New hopes, new dreams. Time. A riveting account of Christopher
Reeve's spinal cord injury.
Sacks, Oliver. 1985. The man who mistook his wife for a hat. New York: Harper & Row. Fascinating tales
of human brain malfunctions.
Salzman, E. W. January 11, 1996. Living with Parkinson's disease. The New England Journal of Medicine,
vol. 334. A review of treatments for Parkinson's disease.
Schwab, Martin E. September 1996. Bridging the gap in spinal cord regeneration. Nature Medicine, vol. 2.
It may be possible one day to heal damaged spinal cords.
Strollo, P.J. Jr. and R.M. Rogers. January 11, 1996. Current concepts: obstructive sleep apnea. The New
England Journal of Medicine, vol. 334. In sleep apnea, people cease breathing often during sleep.
Young, Wise. July 26, 1996. Spinal cord regeneration. Science, vol. 273. Experiments in rats reveal that
spinal cord injuries may be treatable.