In the mammalian heart, the valves open and close because
A) They are under neural control.
B) They are under myogenic control.
C) Changes in chamber pressure cause them to open and close.
D) All of the above
Answer: C
You might also like to view...
Any condition accompanied by severe kidney damage can result in ________, the second most common acid-base disorder.
A) metabolic acidosis B) metabolic alkalosis C) respiratory acidosis D) respiratory alkalosis E) pyelonephritis
The following are steps involved in transmission at the cholinergic synapse:
1. Chemically regulated ion channels on the postsynaptic membrane are activated. 2. Calcium ions enter the axon terminal. 3. An action potential depolarizes the axon terminal at the presynaptic membrane. 4. Acetylcholine is released from storage vesicles by exocytosis. 5. Acetylcholine binds to receptors on the postsynaptic membrane. The correct sequence for these events is A) 2, 4, 1, 3, 5 B) 4, 2, 1, 5, 3 C) 1, 2, 3, 4, 5 D) 3, 2, 4, 5, 1 E) 2, 5, 4, 1, 3
How does surfactant reduce the surface tension of water in the lungs?
A. Reduces hydrogen bonding between water molecules B. Decomposes water C. Covers the alveoli D. All of the choices are correct.
Stem cells that can form all types of lymphocytes are concentrated in the
A) circulation. B) thymus. C) red bone marrow. D) spleen. E) yellow marrow.