Which of the Following Statements is True Regarding Cardiac Muscle

Question

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.

Accepted Answer

Specialized gap junctions, called intercalated discs, are found in cardiac muscle tissue, which allow for rapid transmission of impulses and coordination of contractions. These are not found in skeletal or smooth muscles. The other statements are false; cardiac muscle mainly uses oxidative metabolism, has sarcomeres arranged similar to skeletal muscle, and does not contract faster than skeletal muscle.