College of Massage Therapists of British Columbia (CMTBC) Practice Exam

Do cardiac and smooth muscles have gap junctions?

1. Yes

2. No

3. Only cardiac muscles

4. Only smooth muscles

The correct answer is: Yes

Cardiac and smooth muscles both possess gap junctions, which are specialized intercellular connections that facilitate communication between adjacent cells. In cardiac muscle, gap junctions play a crucial role in ensuring the synchronized contraction of the heart. They allow for the rapid transmission of electrical impulses from one cell to another, enabling coordinated contractions that are vital for efficient cardiac function. Similarly, smooth muscle also contains gap junctions. These connections allow for the spread of signals between smooth muscle cells, promoting coordinated contractions in various structures, such as blood vessels and the gastrointestinal tract. The presence of gap junctions in smooth muscle facilitates processes like peristalsis and vasodilation, where the collective action of muscle cells is necessary. Overall, both types of muscle fibers utilize gap junctions to enhance communication and coordination, which is essential for their respective functions in the body.