What is the Difference Between Multiunit and Visceral Smooth Muscle?

The main difference between multiunit and visceral smooth muscle lies in how individual cells function within the tissue. Here are the key distinctions between the two:

• Multiunit Smooth Muscle:
• Composed of cells that work independently and function separately.
• Found in airways to the lungs and large arteries.
• Cells do not possess gap junctions, and contraction does not spread from one cell to the next.
• Each smooth muscle cell receives its own synaptic input.
• Involuntary in nature, multiunit muscles are neurogenic.
• Visceral Smooth Muscle:
• Also known as single-unit or unitary smooth muscle.
• Composed of cells that work together and function as a single entity.
• Found in the walls of hollow organs, such as the stomach or urinary bladder.
• Cells are connected by gap junctions, allowing for synchronous contraction.
• Exhibits a stress-relaxation response, permitting the muscle to stretch, contract, and relax as the organ expands.
• Involuntary in nature, visceral muscles are myogenic.

In summary, multiunit smooth muscle cells act independently, while visceral smooth muscle cells work together and are dependent on each other for their function. Visceral smooth muscle is responsible for maintaining the function of hollow organs, while multiunit smooth muscle is found in airways and large arteries.

Comparative Table: Multiunit vs Visceral Smooth Muscle

The main difference between multiunit and visceral smooth muscle lies in how the individual cells function. Here is a table comparing the two types of smooth muscle:

Multiunit smooth muscle cells can contract only after stimulation by motor nerve impulses, while visceral smooth muscle is composed of sheets of spindle-shaped cells that function together. Visceral muscle cells depend on each other for their function, and they undergo coordinated movements. Both types of cells are involuntary in nature, but multiunit muscles are neurogenic, while visceral muscles are myogenic.