Which statement is NOT true regarding cardiac muscle?
A) Cardiac muscle cells must obey the all-or-none law of contraction.
B) Calcium-induced calcium release is the process by which extracellular Ca2+ triggers the release of stored Ca2+ from the sarcoplasmic reticulum.
C) Intercalated disks contain both desmosomes for firm attachment and gap junctions to allow communication.
D) Cardiac muscle cells rely on a sarcoplasmic reticulum for storage of Ca2+ ions.
E) The oxygen demand of cardiac muscle cells is high because they have many mitochondria.
A) Cardiac muscle cells must obey the all-or-none law of contraction.
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The smooth muscle cells of the digestive tract need to send electrical signals between each other to contract in unison. The type of intercellular junction best suited for this need is ________.
A. a desmosome B. found in the blood-brain barrier C. a tight junction D. a gap junction
Cryptorchidism
A. results in feminization of the male fetus. B. is the lack of testes. C. is the failure of the testes to descend into the scrotal sac. D. has no effect on fertility. E. may be due to excessive amounts of testosterone in the fetus.
Sperm travels to the ampulla of the ductus deferens before reaching the spermatic cord
Indicate whether the statement is true or false
How would a decrease in the concentration of iron in the blood affect the process of hemostasis?
A) Coagulation would proceed more slowly. B) Platelet plugs would fail to form. C) Retraction would occur prematurely. D) Coagulation would proceed more rapidly. E) There would be no effect.