What Is the Significance of Smooth Muscles Around the Digestive Organs?

Muscle tissue is contractile; it can shorten and thicken. As they contract, muscle cells pull at their attached ends and move body parts. The cells that make up all types of muscle tissues are sometimes called muscle fibers because they are elongated.

The Facts

• The three different types of muscle in the body are smooth muscle, skeletal muscle and cardiac muscle. Skeletal muscles are moved by voluntary effort while cardiac and smooth muscle (around the digestive organs) contract and relax without voluntary control.

Types

• The two major types of smooth muscle are multi-unit smooth muscle and visceral smooth muscle.

Identification

• Multi-unit muscle functions as separate units and is found in the irises of the eyes and walls of blood vessels. Visceral muscle responds as a single unit and is found in the walls of hollow organs.

Features

• Smooth muscle consists of spindle shaped cells with a single nucleus that are shorter than skeletal muscle and not striated like skeletal or cardiac muscle.

Function

• The transmission of impulses from cell to cell, in smooth muscle, is largely responsible for wavelike motions called peristalsis of certain tubular organs, such as the esophagus and intestines. This wavelike pattern pushes food along the digestive tract to mix with digestive fluids.