Which of the following best describes a motor unit?
A) a section of a myofibril from Z disk to Z disk
B) one motor neuron and all the muscle fibers innervated by that neuron
C) all of the neurons that unite to make a whole muscle contract
D) all of the fascicles innervated by several neurons
Ans: B) one motor neuron and all the muscle fibers innervated by that neuron
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The velocity of blood flow is ________.
A) in direct proportion to the total cross-sectional area of the blood vessels B) slower in the arteries than in capillaries because arteries possess a relatively large diameter C) slower in the veins than in the capillaries because veins have a large diameter D) slowest in the capillaries because the total cross-sectional area is the greatest
A person with type B- blood receives a transfusion of type O+ blood. It is his very first blood transfusion. Will there be a transfusion reaction? Why or why not?
A) Yes: the anti-A antibodies of the recipient will clump and hemolyze the donated blood. B) Yes: the recipient has anti-Rh antibodies which will clump and hemolyze the donated blood. C) No: the recipient has no antibodies to the Rh factor because this is his first transfusion. D) Yes: the recipient must receive blood of the same type as his or her own.
Dark, intensely stained, membrane-bound secretory granules are visible in electron micrographs of the cytoplasm of which cell type?
a. Cells of the zona fasciculata of the adrenal cortex b. Follicle cells of the thyroid gland c. Norepinephrine-containing chromaffin cells of the adrenal medulla d. Oxyphil cells of the parathyroid gland e. Pituicytes of the posterior pituitary gland
Neurotransmitters are small, ____________________-acting molecules
Fill in the blank(s) with correct word