Autonomic Nervous System Supplementary Information – Summary Guide

These flashcards cover key concepts related to the autonomic nervous system, its divisions, neurotransmitters, reflex arcs, and related disorders, focusing on definitions and functions.

Somatic Nervous System (SNS)

The division of the nervous system that provides voluntary, conscious control of skeletal muscles.

Autonomic Nervous System (ANS)

The division of the nervous system responsible for involuntary, unconscious regulation of smooth muscle, cardiac muscle, and glands.

Acetylcholine (ACh)

A neurotransmitter released by all somatic motor neurons and some autonomic postganglionic neurons, which can have either excitatory or inhibitory effects.

Norepinephrine (NE)

A neurotransmitter primarily released by postganglionic sympathetic fibers, often associated with the 'fight-or-flight' response.

Parasympathetic Division

The part of the autonomic nervous system that promotes 'rest-and-digest' functions, decreasing heart rate and stimulating digestion.

Sympathetic Division

The part of the autonomic nervous system that prepares the body for 'fight-or-flight' responses, increasing heart rate and blood pressure.

Visceral Reflex Arc

A reflex pathway that involves two consecutive motor neurons (preganglionic and postganglionic) and controls smooth muscle, cardiac muscle, or glands.

Afferent Pathway

The pathways that carry sensory information towards the central nervous system; in visceral reflex arcs, these are visceral sensory neurons.

Autonomic Tone

The baseline level of activity of both the sympathetic and parasympathetic divisions at rest, allowing for continuous regulation of organ function.

Dynamic Antagonism

The opposing effects of the sympathetic and parasympathetic divisions on the same organ, ensuring homeostasis is maintained.

Cholinergic Receptors

Receptors that respond to acetylcholine, including nicotinic and muscarinic types, which have different effects on target organs.

Adrenergic Receptors

Receptors that respond to norepinephrine and epinephrine, with different subtypes (α and β) that mediate various physiological responses.

Epinephrine (EPI)

A hormone released by the adrenal medulla, acting on adrenergic receptors to induce widespread sympathetic responses.

Beta Blockers

Medications that block β-adrenergic receptors, used to reduce heart rate, blood pressure, and trembling, often banned in certain sports for affecting performance.

Renin Release from Kidneys

The process stimulated by sympathetic impulses that triggers the formation of hormones raising blood pressure.

Homeostasis

The state of steady internal conditions maintained by biological systems, which the autonomic nervous system helps regulate.

Thermoregulatory Responses

Responses of the sympathetic division to regulate body temperature through vasodilation or vasoconstriction of blood vessels and activation of sweat glands.