During the contraction phase of a muscle twitch,
A. acetylcholine stimulates the pre-synaptic terminal.
B. sodium ions diffuse into the muscle fiber.
C. actin-myosin cross-bridges form.
D. calcium ions are transported back to the sarcoplasmic reticulum.
E. the action potential travels down the T tubule.
C
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Atropine inhibits parasympathetic activity. Discuss the effects of atropine on the heart and describe common expected side effects.
What will be an ideal response?
Generally, a decrease in substrate concentration leads to an increase in reaction rate.
Answer the following statement true (T) or false (F)
During the contractions of gastric emptying
A. the strongest contractions are in the antrum of the stomach because the intrinsic pacemaker frequency is fastest there. B. the pyloric sphincter opens to allow stomach contents to pass quickly and completely into the duodenum. C. the strength of stomach wall contractions is increased when the duodenum secretes cholecystokinin. D. the pyloric sphincter closes to allow only a small amount of liquefied chyme to pass into the duodenum with each contraction of the stomach. E. the stomach is induced to contract by increased sympathetic activity.
Luteinizing hormone (LH) binds to interstitial (Leydig) cells and
A. inhibits sustentacular cells. B. promotes sperm cell production by the interstitial cells. C. decreases testosterone production by the interstitial cells. D. stimulates GnRH levels to increase in the testes. E. increases testosterone production by the interstitial cells.