The Autonomic Nervous System and Visceral Reflexes

Practice flashcards covering key vocabulary and concepts related to the autonomic nervous system and visceral reflexes.

Autonomic Nervous System (ANS)

A motor nervous system that controls glands, cardiac muscle, and smooth muscle; also known as the visceral motor system.

Homeostasis

The state of steady internal conditions maintained by living things, a term coined by Walter Cannon.

Denervation hypersensitivity

Exaggerated responses of cardiac and smooth muscle if autonomic nerves are severed.

Visceral reflexes

Unconscious, automatic, stereotyped responses to stimulation involving visceral receptors and effectors.

Sympathetic division

A division of the ANS that prepares the body for physical activity; also known as the fight-or-flight response.

Parasympathetic division

A division of the ANS that calms the body down, reducing energy expenditure and assisting in bodily maintenance.

Autonomic tone

The normal background rate of activity that represents the balance of the two systems (sympathetic and parasympathetic) according to the body’s needs.

Preganglionic neurons

Neurons that originate in the brainstem or spinal cord and synapse with postganglionic neurons in the autonomic ganglion.

Dual innervation

A condition where most visceral organs receive nerve fibers from both the sympathetic and parasympathetic divisions.

Cholinergic fibers

Axons that secrete acetylcholine (ACh).