Select the correct statement about efferent neurons.
a. their cell bodies are located in dorsal root ganglia.
b. they are part of a two-neuron chain in the autonomic nervous system.
c. they arise peripherally at a receptor.
d. they send information toward the central nervous system.
e. they signal only skeletal muscles.
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Question 2) Urea
a. reabsorption occurs passively in the distal tubules
b. is only 50 reabsorbed in the proximal tubule.
c. is not normally found in the urine because it is completely reabsorbed
d. reabsorption is controlled by aldosterone
e. has a clearance value of 0
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Question 3) What would occur if ACh was not removed from the nicotinic receptors on skeletal muscle cells?
a. the cell would relax.
b. the cell would repolarize with the opening of chloride channels.
c. the cell would remain contracted until fatigued.
d. sodium would continue to move into the cell causing excitation.
e. both (c) and (d) above.
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Question 4) Urea
a. is the waste product with the smallest molecular size in the glomerular filtrate.
b. is in greater concentration at the end of the proximal tubule than in other body fluids.
c. has a clearance rate greater than GFR.
d. both (a) and (b) above are correct.
e. all of these answers.
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Question 5) What is the fate of ACh following binding to receptors?
a. it remains bound causing continued excitement.
b. it is removed by the enzyme acetylcholinesterase.
c. it is actively reabsorbed the axon terminal.
d. it is passively reabsorbed by the muscle cell.
e. none of these answers.
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Question 6) Water reabsorption
a. cannot occur from any portion of the nephron in the absence of vasopressin.
b. occurs to the greatest extent in the proximal convoluted tubule.
c. is under vasopressin control in the proximal tubule.
d. is under vasopressin control in the distal and collecting tubules.
e. both (b) and (d) above.
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Question 7) Which of the following is the final signaling step following impulse conduction along the axon terminal?
a. ACh binds with receptors on the muscle cell membrane, opening sodium channels.
b. ACh diffuses across the cleft of the junction.
c. ACh is released by exocytosis.
d. calcium diffuses into the terminal button.
e. voltage-gated channels for calcium are opened.
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Question 8) Which of the following statements concerning water reabsorption is correct?
a. water reabsorption is under control of vasopressin throughout the length of the nephron.
b. the ascending limb of the loop of Henle is always impermeable to water.
c. vasopressin makes the distal and collecting tubules impermeable to water.
d. fifteen percent of the filtered water osmotically follows the absorption of Na+ and other solutes in the proximal tubule.
e. water reabsorption is passive in the early portions of the nephron but is active in the distal portions of the nephron.
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Question 9) Acetylcholine
a. is released from an axon.
b. destroys acetylcholinesterase.
c. is blocked by sodium.
d. both (a) and (b) above.
e. all of these answers.
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Question 10) Water reabsorption
a. occurs passively by osmosis in the proximal tubule.
b. is under the control of vasopressin in the distal and collecting tubules.
c. occurs by active transport in the distal and collecting tubules.
d. both (a) and (b) above.
e. all of these answers.
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