Question

Which of the following is true about cardiac muscle cells?

• A. They lack an orderly arrangement of actin and myosin filaments
• B. They have less extensive sarcoplasmic reticulum and thus contract more slowly than smooth muscle.
• C. They are connected by intercalated discs, through which action potentials spread to all cells in the heart.
• D. They have a relatively low sodium permeability with resting potentials more positive than an action potential threshold

Answer 1

The correct option is C They are connected by intercalated discs, through which action potentials spread to all cells in the heart.

• Each cardiac muscle has a single centrally located nucleus.
• Cardiac muscle cells are striated due to a similar arrangement of contractile proteins.
• They mainly function in the pumping of oxygen-rich blood throughout the body to provide cells with vital nutrients.
So, the correct option is 'They are connected by intercalated discs, through which action potential spread to all cells in the heart'.