Anatomy and Physiology of the Human Nervous System

  Discuss the role of the autonomic nervous system (ANS) in regulating involuntary functions in the human body, with a particular focus on the sympathetic and parasympathetic divisions. How do these divisions maintain homeostasis during a sudden stressful event, such as being startled? Include in your discussion how neurotransmitters like norepinephrine and acetylcholine contribute to these processes.