Questions: Question 5 pts Cardiac muscle, like skeletal muscle, uses multiple motor unit summation to control the length and force of contraction. True False Question 6 1 pts The effect of endurance-type athletic training may be to lower the heart rate. This phenomenor: results in decreased cardiac output. is caused by hypertrophy of the heart muscle. does not occur in aerobic training. is a sign of dangerous overexertion. Question 7 1 pts Compared to skeletal muscle, cardiac muscle: has gap junctions that allow it to act as a functional syncytium. lacks striations, cells are larger than skeletal muscle cells, has more nuclej per cell,

Question 5:
The answer is False.
Explanation: Cardiac muscle does not use multiple motor unit summation like skeletal muscle. Instead, cardiac muscle cells are connected by intercalated discs, which allow for the synchronized contraction of the heart muscle as a whole unit.

Question 6:
The answer is the second one: is caused by hypertrophy of the heart muscle.
Explanation: Endurance-type athletic training often leads to hypertrophy of the heart muscle, particularly the left ventricle, which increases the efficiency of the heart. This can result in a lower resting heart rate, as the heart can pump more blood per beat. This is not a sign of dangerous overexertion, nor does it result in decreased cardiac output; rather, it is a normal adaptation to aerobic training.

Question 7:
The answer is the first one: has gap junctions that allow it to act as a functional syncytium.
Explanation: Cardiac muscle cells are connected by gap junctions, which facilitate the rapid transmission of electrical signals, allowing the heart to contract as a coordinated unit (functional syncytium). Cardiac muscle is striated, similar to skeletal muscle, but the cells are generally smaller and have one or two nuclei per cell, not more.