The Autonomic Nervous System and Visceral Reflexes

These flashcards cover key concepts related to the Autonomic Nervous System (ANS) and visceral reflexes, important for understanding body functions and responses.

Autonomic Nervous System (ANS)

A motor nervous system that controls glands, cardiac muscle, and smooth muscle.

Viscera

Organs located in body cavities.

Autonomic

Not under voluntary control; operates without conscious awareness.

Visceral Reflexes

Automatic responses to stimuli involving internal organs, such as the baroreflex.

Sympathetic Division

Part of ANS responsible for 'fight or flight' responses.

Parasympathetic Division

Part of ANS responsible for 'resting and digesting' functions.

Efferent Pathways

Pathways that carry signals away from the central nervous system to the target organs.

Preganglionic Fiber

The first neuron in the autonomic pathway, which is myelinated.

Postganglionic Fiber

The second neuron in the autonomic pathway, which is typically unmyelinated.

Dual Innervation

The situation where an organ is innervated by both sympathetic and parasympathetic fibers.

Cholinergic Fibers

Nerve fibers that release acetylcholine (ACh).

Adrenergic Fibers

Nerve fibers that release norepinephrine (NE).

Nicotinic Receptors

Cholinergic receptors that are always excited by acetylcholine.

Muscarinic Receptors

Cholinergic receptors that may be excited or inhibited by acetylcholine.

Epinephrine

A hormone more active on beta receptors, often used in medical emergencies.

Norepinephrine

A neurotransmitter more active on alpha receptors, often influencing blood pressure.

Sympathomimetics

Drugs that enhance sympathetic responses.

Parasympathomimetics

Drugs that enhance parasympathetic responses.

Higher-Level Control of the ANS

Involves structures like the cerebral cortex and hypothalamus that regulate autonomic functions.