Question

Sympathetics and parasympathetics usually act ________________, with a balance between them that is regulated by the brain. Most internal organs receive both kinds of innervation and the brain regulates the balance between them. However, the arteries to some internal organs receive only _______________ (on/off).

Answer 1

The sympathetic and parasympathetic nervous systems act in an antagonistic balance, regulated by the brain to maintain homeostasis, with most organs receiving dual innervation. Some arteries, however, are only innervated by the sympathetic system.

Step-by-step explanation:

The autonomic nervous system includes two critical divisions: the sympathetic and the parasympathetic nervous systems. These systems often act antagonistically, with a balance between them that is regulated by the brain, a concept known as homeostasis. Most internal organs are innervated by both systems, where one system may excite while the other inhibits, allowing for refined control over the organ's function. However, some internal organs, specifically arteries to some internal organs, receive only sympathetic innervation, which means they can be turned on or off under this system's control without a direct parasympathetic counterpart.