MICROANATOMY

Detailed explanation-1: -The complex nature of the autonomic nervous system allows for tight unconscious control of digestions, respiratory rate, urination, heart rate, blood pressure, and many other critical body functions. Ultimately innervation from the autonomic nervous system leads to a calcium release in smooth muscle tissue.

Detailed explanation-2: -The autonomic system usually is defined as a motor system that innervates three major types of tissue: cardiac muscle, smooth muscle, and glands.

Detailed explanation-3: -Sympathetic innervation promotes vascular smooth muscle differentiation | American Journal of Physiology-Heart and Circulatory Physiology.

Detailed explanation-4: -Smooth muscle, found in the walls of the hollow internal organs such as blood vessels, the gastrointestinal tract, bladder, and uterus, is under control of the autonomic nervous system. Smooth muscle cannot be controlled consciously and thus acts involuntarily.