Smooth muscle cells of blood vessels are described as integrating centers. Outline the various inputs that affect smooth muscle cells and how those are integrated.

Question

What will be an ideal response?

Answer 1

Myogenic responses, autonomic neurotransmitters, and paracrine mediators all affect smooth muscle cells. Myogenic responses involve alterations in stretch of the overlying smooth muscle cells in blood vessels when the pressure inside of them is altered. The autonomic neurotransmitters bind to receptors that affect second messenger signaling through intracellular inositol trisphosphate (IP3) or cAMP concentration to increase or decrease respectively) the force generation by the smooth muscle cells. Paracrine and endocrine mediators also bind to receptors on smooth muscle cells to alter second messenger signaling. In the end, it is the balance of myosin light chain kinase and myosin light chain phosphatase activity that determines how much force a smooth muscle generates and thereby how it will respond to the various signals that it is receiving.