Under the influence of the trophoblast, maternal blood vessels in the endometrium
A) disappear.
B) attach to the inner cell mass.
C) break down and form lacunae.
D) form a capillary network in the trophoblast.
E) increase in size and penetrate the blastocyst.
Answer: C
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If precapillary sphincters relax, local blood flow in the capillary bed ________; if this occurs in several capillary beds at the same time, and no other circulatory changes occur, then systemic blood pressure ________.
A. increases; decreases B. increases; increases C. decreases; decreases D. decreases; increases
Most of a membrane potential is established by the passive movement of different cations into and out of a cell
Indicate whether the statement is true or false
Which of the following statements about voltage-gated sodium channels is true?
a. All cells contain voltage-gated sodium channels. b. Voltage-gated sodium channels are integral membrane proteins. c. Voltage-gated sodium channels have roughly equal permeability to Na+ and K+. d. Voltage-gated sodium channels open in response to any change in membrane potential. e. Voltage-gated sodium channels open in response to binding of acetylcholine.
When light encounters a medium of different density, it is bent or
A) reflected. B) refracted. C) absorbed. D) transduced. E) propagated.