| Arrangement |
Arranged in a circular or ring-like fashion around a body structure |
Arranged lengthwise along a body structure |
| Location |
Often found in tubular structures, such as sphincters |
Located as the walls of blood vessels or the digestive tract |
| Function |
Contraction of these muscles reduces the diameter or circumference of a tubular structure |
Contraction of these muscles shortens the length of a structure |
| Control of Openings |
Often associated with controlling the openings of organs e.g., regulating the passage of materials in the digestive system |
May play a role in controlling the size or diameter of tubular structures |
| Appearance |
Often forms a circular band around a tubular structure |
Typically appears as parallel bundles along the length of a structure |
| Examples
|
· Sphincter muscles in the digestive system
· Iris muscles in the eye |
· Muscles in the walls of blood vessels
· Muscles in the digestive tract responsible for peristalsis |
