Chapter 4 - Muscle Tissue
Muscle tissue is composed of cells that maintain the contractile function of connective tissue. Three types of muscle tissue are recognized based on their structure, function, and location:
- Skeletal muscle cells - striated, voluntary control
- Cardiac muscle cells - striated, involuntary control
- Smooth muscle cells - nonstriated, involuntary control
In all types of muscle, contraction is caused by the movement of myosin filaments along actin filaments.
The terms muscle fiber and muscle cell are synonymous.
Skeletal Muscle
Skeletal muscle fibers, also known as myofibers, are long, cylindrical cells that are quite large, often spanning the entire length of a muscle.
A sarcomere is the fundamental contractile unit of striated muscle fibers.
Cardiac Muscle
Cardiac muscle cells has branching fibers, a single, centrally located nucleus, show the same striations as skeletal muscle, and are under involuntary control.
Smooth Muscle
Smooth muscle cells are spindle-shaped (fusiform), have a single, centrally located nucleus, lack striations, and are under involuntary control.
