Final answer:
Nitric oxide triggers smooth muscle relaxation by binding to receptors in smooth muscle tissue in the blood vessel wall. This leads to vasodilation and increased blood flow.
Step-by-step explanation:
Nitric oxide (NO) triggers smooth muscle relaxation in the blood vessel wall by interacting with receptors in the smooth muscle tissue. When NO is released, it diffuses across the plasma membrane and binds to these receptors, activating a signaling pathway that results in the relaxation of the smooth muscle.
For example, when nitroglycerin is used as a treatment for heart disease, it triggers the release of NO. This causes blood vessels to dilate, allowing for increased blood flow to the heart.
Overall, nitric oxide plays a crucial role in regulating vascular tone and blood flow by inducing smooth muscle relaxation in the blood vessel walls.