Which of the following statements is true regarding cardiac muscle?
A) Its main source of ATP production is glycogen.
B) The actin and myosin myofilaments are not arranged in sarcomeres.
C) Cardiac muscle preferentially metabolizes anaerobically.
D) There are specialized gap junctions in cardiac muscle not found in skeletal or smooth muscles.
E) Cardiac muscle goes into sustained contractions faster than skeletal muscle.
D
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Regarding fertilization, which of the following events happens first?
A) The fast block to polyspermy B) The cortical reaction C) The acrosomal reaction D) The slow block to polyspermy E) Formation of a fertilization membrane
Heat energy gained from muscle contraction is released by the ________ system
A) integumentary B) respiratory C) cardiovascular D) urinary E) endocrine
What is responsible for initiating contraction of smooth muscle?
a. stimulation by motor neurons b. inhibition of acetylcholinesterase c. membrane potential drifting to threshold as a result of automatic changes in ion movement across the membrane d. excitation of the gap junctions by transmitter substance e. stimulation by the autonomic nervous system
The three subdivisions of the small intestine are duodenum, jejunum, and ileum
Indicate whether the statement is true or false