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Which characteristics describe cardiac muscles?

a) Striated, usually uninucleate, branching
b) Smooth muscle has little SR
c) Smooth muscle is uninucleate
d) Their membranes undergo voltage changes when stimulated

1 Answer

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Final answer:

Cardiac muscles are striated, branching, and responsible for the heart's contraction. They have unique properties, including autorhythmicity and intercalated discs, which allow cell synchronization. Cardiac muscles pump blood through the body and are under involuntary control.

Step-by-step explanation:

Cardiac muscles are striated, usually uninucleate, and branching. They are found only in the heart and are responsible for its contraction. Unlike skeletal muscle fibers, which are arranged in parallel bundles, cardiac muscle fibers connect at branching angles called intercalated discs.

One unique characteristic of cardiac muscle is its ability to initiate an electrical potential at a fixed rate that spreads rapidly from cell to cell, triggering the contractile mechanism. This property is known as autorhythmicity and is responsible for the heart's intrinsic rhythm without external stimulation. Cardiac muscle also contains intercalated discs, which have both anchoring junctions and gap junctions, allowing cells to synchronize their actions.

Overall, cardiac muscles are essential for pumping blood through the body and are under involuntary control.

User Christian Groleau
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