Muscle Tissue Properties and Structure

Study Notes

Muscle tissue comprises specialized cells called muscle cells or myocytes (muscle fibers)
Myocytes contain protein filaments known as actin and myosin
Muscle tissue is described as striated or non-striated based on the presence or absence of striations
Striations are formed by the arrangement of actin and myosin filaments within myocytes

Skeletal muscle is the most common type of muscle tissue in the body
Skeletal muscle cells are elongated, multinucleate, and non-branching
Skeletal muscle cells fuse to form syncytia
The fusion of myoblasts forms skeletal muscle cells/myocytes
Skeletal muscle is often referred to as 'voluntary' muscle, but it is involved in both conscious and subconscious movements

Cardiac muscle is striated and contains contractile proteins arranged into sarcomeres
Cardiac muscle cells are shorter and broader than skeletal muscle cells, and branched at their ends
Cardiac muscle cells are typically uninucleate, sometimes binucleate, and the nucleus is centrally located
Striations in cardiac muscle are less defined than in skeletal muscle
Cardiac muscle cells are surrounded by loose connective tissue, similar to endomysium, but less organized

Smooth muscle is found in the walls of tubular structures and hollow organs
Smooth muscle cells are smaller and shorter than skeletal muscle cells, and uninucleate
Smooth muscle cells are spindle-shaped with long tapered ends and are packed together
Smooth muscle is subject to subconscious/involuntary control