Medical Dictionary
Sympathetic Nervous System
The sympathetic nervous system is one of two sections of the autonomic nervous system (the other being the parasympathetic nervous system). The autonomic nervous system is the section of the nervous system that controls involuntary muscle movement such as that of smooth muscles (e.g. in the genitals) and the muscles of the heart. Nerves in the sympathetic nervous system emerge from the spinal cord to innervate the heart, lungs, sweat glands and abdominal organs. The sympathetic nerves release noradrenaline, which may be excitatory or inhibitory. The sympathetic nervous system regulates heartbeat, blood pressure and pupil dilation. |
