Smooth muscle is nonstriated involuntary muscle

Longitudinal layer of smooth muscle

the muscle fibers run parallel to the long axis of the organ.

Smooth muscle lacks the coarse connective tissue sheaths found in the skeletal muscle

A small amount of fine connective tissue is secreted by the smooth muscle themselves

Smooth muscle fibers are small spindle-shaped cells

Each cell has one centrally located nucleus. 5-10 um and 30-200 um long

Regulation of Contraction

Skeletal muscles are voluntary Cardiac and smooth muscles are involuntary

Cells exhibit individual neuromuscular junctions

Skeletal: Yes Cardiac: NO Smooth: Not unitary muscle; yes in multiunit muscle

Circular layer of smooth muscle

The fibers run around the circumstances of the organ

Smooth muscle has varicosities instead of neuromuscular junction

The innervating nerve fibers of the autonomic nervous system have numerous bulbous swelling call Varicosities.

Smooth muscle fibers have less elaborate SR and No T-Tubules.

The sarcoplasmic reticulum of smooth muscle fibers has no terminal cistern and lacks a specific pattern relative to the myofilaments