Select the correct statement about the neuromuscular junction.
a. AChE activity is absent here.
b. It involves presynaptic neurons of the autonomic nervous system.
c. It is a junction between two neurons.
d. It is always excitatory.
e. The axon terminals do not store neurotransmitters.
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Question 2) Tubular secretion is important
a. in the renal regulation of hydrogen ion concentration.
b. for the elimination of metabolic waste products from the body.
c. in the renal regulation of sodium balance.
d. both (a) and (b) above.
e. all of these answers.
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Question 3) Curare
a. strongly binds to acetylcholine receptor sites.
b. inhibits acetylcholinesterase.
c. is found in pesticides and military nerve gases.
d. two of these answers.
e. all of these answers.
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Question 4) Tubular secretion
a. involves transepithelial transport.
b. is the movement of a substance from the peritubular capillary blood into the tubular fluid.
c. always occurs by active transport.
d. both (a) and (b) above.
e. both (b) and (c) above.
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Question 5) Which of the following chemicals paralyzes skeletal muscle by binding to the acetylcholine receptor sites?
a. black widow spider venom.
b. curare.
c. organophosphates.
d. DDT.
e. local anesthetics.
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Question 6) Tubular secretion
a. refers to the movement of a substance from the peritubular capillary blood into the tubular lumen.
b. can occur by active or passive transport mechanisms.
c. of K+ occurs in the distal and collecting tubules and is stimulated by aldosterone.
d. of organic anions and cations occurs in the proximal tubule by two distinct types of carriers.
e. all of these answers.
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Question 7) Botulism is caused by a toxin from the bacterium of the group (genus)
a. Clostridium.
b. Escherichia.
c. Salmonella.
d. Staphylococcus.
e. Streptococcus.
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Question 8) When the extracellular fluid becomes too acidic, the tubular secretion of
a. no ionic substance is affected.
b. hydrogen ions decreases.
c. hydrogen ions increases.
d. sodium ions decreases.
e. sodium ions increases.
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Question 9) Select the CNS structure that does not influence autonomic activity.
a. medulla.
b. hypothalamus.
c. spinal cord.
d. cerebellum
e. all these answers.
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Question 10) Urea
a. is a waste product resulting from the breakdown of protein.
b. is passively reabsorbed at the end of the proximal tubule down a urea concentration gradient created by the osmotic-induced reabsorption of water from the proximal tubule.
c. recycling between the late portion of the collecting tubule and the long loops of Henle contributes to medullary hypertonicity.
d. both (a) and (b) above.
e. all of these answers.
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