In humans, the blood vessels of the allantois become the umbilical blood vessels?
a. true
b. false
Ans: a. true
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Which muscles attached to hair follicles cause "gooseflesh"?
A) arrector pili B) arrector integument C) arrector folliculi D) skeletal muscle
Relaxin is a hormone produced by the placenta and ovaries. The function of this hormone is to ________
A) ensure the implantation of the blastula B) block the pain of childbirth C) prevent morning sickness D) relax the pubic symphysis
A drop in blood glucose concentration would likely cause
a. increased release of ACh onto autonomic effectors b. decreased frequency of impulses along short preganglionic neurons c. increased frequency of autonomic impulses from the lumbar region of the spinal cord d. decreased binding of neurotransmitters to alpha-2 receptors in the pancreas e. all of the above
All of the following are true statements EXCEPT:
A) The cells of lymphatic capillaries are tightly joined. B) Lymphatic vessels operate under low-pressure. C) Lymphatic vessels belong to a one-way system that drains lymphatic capillaries. D) Lymph flow is driven in part by contraction of smooth muscle in the walls of lymph-collecting vessels.