Question

multiple choice question

what type of smooth muscle is found in the digestive tract, respiratory tract, and urinary tract?

multiunit
varicose
voluntary
single-unit

Explanation:

Identify smooth muscle types

Using the Smooth Muscle Characteristics knowledge point
Smooth muscle is broadly classified into two functional types based on how the muscle fibers are stimulated and contract: multiunit smooth muscle and single-unit (visceral) smooth muscle.

Analyze single-unit smooth muscle

Single-unit smooth muscle cells are electrically coupled by gap junctions, allowing them to contract together as a single coordinated unit. This type is typically found in the walls of hollow visceral organs, including the digestive tract, respiratory tract, and urinary tract.

Analyze other options

Multiunit smooth muscle cells act independently and are found in large airways, large arteries, arrector pili muscles, and the iris. "Varicose" refers to dilated veins, and "voluntary" describes skeletal muscle, not smooth muscle.

Answer:

• Multiunit
• Varicose
• Voluntary
• Single-unit (Correct answer)