a& p chapter 10

Topics: Spinal cord, Neuron, Action potential Pages: 12 (2254 words) Published: November 29, 2013
Chapter 10-12: Nervous System & Special Senses
1. Masses of myelinated nerve fibers appear
a. white.
b. gray.
c. brown.
d. transparent.
Answer: A
2. Which of the following lists the parts of a reflex arc in the correct sequence? a. receptor, sensory neuron, motor neuron, interneuron, effector b. effector, receptor, sensory neuron, motor neuron, interneuron c. effector, sensory neuron, receptor, interneuron, motor neuron d. receptor, sensory neuron, interneuron, motor neuron, effector Answer: D

3. When a nerve fiber is polarized, the concentration of
a. sodium and potassium ions is higher on the inside of its membrane. b. sodium and potassium ions is higher on the outside of its membrane. c. sodium ions is higher on the inside of its membrane and potassium ions is higher on the outside. d. sodium ions is higher on the outside of its membrane and potassium ions is higher on the inside. Answer: D

4. Saltatory conduction
a. occurs only if the myelin sheath is continuous.
b. occurs only if nodes of Ranvier are lacking.
c. is faster than conduction on an unmyelinated fiber.
d. is slower than conduction on an unmyelinated fiber.
Answer: C
5. The most rapid nerve impulses are conducted on fibers that are a. thick and myelinated.
b. thick and unmyelinated.
c. thin and myelinated.
d. thin and unmyelinated.
Answer: A
6. The nervous system
a. detects changes in the internal or external environment. b. controls the movement of muscles and secretions of glands. c. integrates information from several sources and uses it to make an appropriate response. d. all of the above

Answer: D
7. Which of the following neurotransmitters functions to relieve pain sensations? a. beta-endorphin
b. acetylcholine
c. epinephrine
d. dopamine
Answer: A

8. What is the correct sequence of these events that follow a threshold potential? 1. The membrane becomes depolarized.
2. Sodium channels open and sodium ions diffuse inward.
3. The membrane becomes repolarized.
4. Potassium channels open and potassium ions diffuse outward. a. 3, 2, 4, 1
b. 2, 1, 4, 3
c. 1, 2, 4, 3
d. 4, 1, 3, 2
Answer: B
9. Most of the neurons in the brain and spinal cord are
a. bipolar.
b. unipolar
c. multipolar.
d. nonpolar
Answer: C
10. Reflexes help to control
a. heart rate.
b. blood pressure.
c. digestive activities.
d. all of the above
Answer: D
11. An infant’s response to stimuli are coarse and undifferentiated because its nerve fibers a. have not yet appeared.
b. are incapable of carrying impulses.
c. have not yet developed connections to the brain.
d. are not completely myelinated.
Answer: D
12. During an action potential, calcium ions cause
a. potassium channels to open.
b. potassium channels to close.
c. sodium channels to open.
d. sodium channels to close.
Answer: D
13. A decreased blood calcium concentration is likely to be accompanied by a. tetanic skeletal muscle contractions.
b. paralysis of skeletal muscles.
c. loss of vitamin D.
d. diarrhea.
Answer: A
14. Drugs that decrease membrane permeability to sodium
a. are used as local anesthetics.
b. prevent nerve impulses from passing.
c. cause a loss in the perception of pain.
d. all of the above
Answer: D

15. The Babinski reflex, in which the great toe extends upward and the smaller toes fan apart, a. may indicate immaturity of the corticospinal tract.
b. may indicate an injury to the corticospinal tract.
c. is abnormal in adults.
d. all of the above
Answer: D
16. Three general functions of the nervous system are
a. sensory, motor, and predictive.
b. integrative, motor, and sensory.
c. predictive, manipulative, and integrative.
d. reflexive, sensory, and predictive.
Answer: B
17. Myelin is defined as
a. an outer membrane on a neuroglial cell.
b. a lipoprotein cell membrane on the outside of axons.
c. a mass of white lipid material that surrounds the cell body of a neuron. d....
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