Objectives

• Describe the different types of muscle

• Explain contractibility and extensibility

1. skeletal muscle

2. cardiac muscle

3. smooth muscle

Muscle is one of the four primary tissue types of the body, and the body contains three types of muscle tissue.

Tissue types

​elasticity-ability to stretch and rebound

excitability-ability to undergo neural stimulation

​extensibility-ability to lengthen (extend)

​Contractility-ability to shorten (contract) forcibly

cardiac

smooth

skeletal​

​Vocabulary Words

Skeletal muscle fibers are multinucleated structures that compose the skeletal muscle.

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​Skeletal muscle

Cardiac muscle fibers each have one to two nuclei and are physically and electrically connected to each other so that the entire heart contracts as one unit (called a syncytium).

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Cardiac muscle

The actin and myosin are not arranged in such regular fashion in smooth muscle, the cytoplasm of a smooth muscle fiber (which has only a single nucleus) has a uniform, nonstriated appearance (resulting in the name smooth muscle).

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​Smooth muscle