What happens when acetylcholine stimulates its receptors in the neuromuscular junction?
A) The inhibitory effect of acetylcholinesterase is overridden.
B) The threshold of the muscle fiber lowers.
C) The release of Ca2+ from the sarcoplasmic reticulum decreases.
D) The permeability of the sarcolemma to Na+ increases.
E) The positive charge on the sarcolemma decreases.
D
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Lymphatic capillaries owe their permeability to the presence of:
A. an open end that siphons fluid from the interstitial fluid. B. minivalves in their walls. C. tight junctions between adjacent cells. D. proteins in the lymph fluid.
Parasympathetic stimulation ____ heart rate and ____ the motility in the digestive tract
a. does not affect, increases. b. decreases, decreases. c. decreases, increases. d. increases, decreases. e. increases, increases.
In the small intestine, fat soluble vitamins are
a. digested by lipases b. actively absorbed c. absorbed in micelles d. absorbed through cotransport with sodium ions e. passively absorbed with anions
Which of the following is a nutritional requirement for developing the red blood cells necessary for pregnancy?
A. Fat B. Folic acid C. Iron D. Calcium