Smooth muscle tissue

Definition

Smooth muscle tissue is a type of muscle that is non-striated and involuntary, found primarily in the walls of hollow organs. It functions to propel substances through these organs via coordinated contractions.

5 Must Know Facts For Your Next Test

1. Smooth muscle cells are spindle-shaped and have a single central nucleus.
2. These muscles are controlled by the autonomic nervous system, not by conscious effort.
3. Smooth muscle contraction is slower and more sustained compared to skeletal muscle.
4. They contain actin and myosin filaments but lack the sarcomeres seen in striated muscles.
5. Calcium ions play a critical role in initiating smooth muscle contraction by interacting with calmodulin.

Review Questions

• What type of control regulates smooth muscle tissue?
• Where in the body would you primarily find smooth muscle tissue?
• How do the contraction characteristics of smooth muscle compare to those of skeletal muscle?

Related terms

Skeletal Muscle Tissue: Striated, voluntary muscles attached to bones for movement.

Cardiac Muscle Tissue: Striated, involuntary muscles found only in the heart.

Autonomic Nervous System: Part of the nervous system controlling involuntary actions like heart rate and digestion.