In which type of smooth muscle do graded contractions occur by recruitment of additional muscle fibers?
A) multi-unit
B) single-unit
C) both multi- and single-unit
D) smooth muscles do not have graded contractions

Question

Quizplus · Accepted Answer

Graded contractions by recruitment of additional muscle fibers occur in multi-unit smooth muscle, where each fiber is innervated independently and can contract separately. In single-unit smooth muscle, all fibers contract together as a unit and do not exhibit graded contractions.

In Which Type of Smooth Muscle Do Graded Contractions Occur