Question

Which of the following is NOT a property of single-unit smooth muscles?

A) All smooth muscle cells are connected by gap junctions.
B) Their contraction occurs in a coordinated manner.
C) Electrical responses travel directly between cells.
D) Only a proportion of the smooth muscle cells receive autonomic nervous input.
E) Each cell functions independent of its neighbor.

Answer 1

Single-unit smooth muscle cells are connected by gap junctions, allowing for synchronized contractions. Electrical responses travel directly between cells in this type of muscle tissue, which does not function independently of its neighboring cells.

Step-by-step explanation:

Single-unit smooth muscle cells are unique in that all smooth muscle cells are connected by gap junctions, allowing for the synchronization of electrical responses and coordinated contractions. This type of muscle tissue functions as a syncytium, where each cell is interconnected physically and electrochemically, working together as a single unit. In contrast, multiunit smooth muscle cells do not possess gap junctions, and contraction does not spread from one cell to the next. Instead, contraction is confined to the originally stimulated cell. Therefore, the property that is NOT associated with single-unit smooth muscles is E) Each cell functions independent of its neighbor.