Question

Unlike skeletal muscle, cardiac muscle is highly resistant to Lactate-mediated fatigue because cardiac muscle

A. uses aerobic respiration in mitochondria for energy
b. Operates with electrical energy supplied by SA node
c. primarily metabolizes glucose using the fermentation pathway
d. Does not need oxygen for production of energy

Answer 1

Cardiac muscle undergoes aerobic respiration patterns, primarily metabolizing lipids and carbohydrates. This muscle type has long refractory periods followed by brief relaxation periods to prevent tetany and allow the heart to pump blood.

Step-by-step explanation:

Cardiac muscle undergoes aerobic respiration patterns, primarily metabolizing lipids and carbohydrates. Myoglobin, lipids, and glycogen are all stored within the cytoplasm. Cardiac muscle cells undergo twitch-type contractions with long refractory periods followed by brief relaxation periods.

The relaxation is essential so the heart can fill with blood for the next cycle. The refractory period is very long to prevent the possibility of tetany, a condition in which muscle remains involuntarily contracted. In the heart, tetany is not compatible with life, since it would prevent the heart from pumping blood.