the part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands
"The autonomic nervous system regulates vital functions like heartbeat, digestion, and breathing without conscious effort."
plural of an
"The doctor explained that the patient's symptoms were caused by an issue with their ANS, which regulates involuntary bodily functions like heart rate and digestion."
Abbreviation of answer.
Initialism of autonomic nervous system.
"My friends are always asking for my answers when I get good grades on their math tests."