The Autonomic Nervous System

These flashcards cover major terms and concepts related to the Autonomic Nervous System, including its divisions, functions, and key characteristics.

Autonomic Nervous System

Called the involuntary motor or visceral nervous system; consists of the sympathetic and parasympathetic divisions.

Somatic Nervous System

Controls voluntary responses and innervates skeletal muscles.

Sympathetic Division

The 'fight-or-flight' system that prepares the body for stressful situations.

Parasympathetic Division

The 'rest-and-digest' system that conserves energy and directs maintenance activities.

Efferent Pathways

The pathways through which signals are sent from the CNS to effectors; differ between somatic and autonomic systems.

Neurotransmitter

Chemical messengers released by neurons; in the ANS includes acetylcholine and epinephrine.

Preganglionic Neuron

The first neuron in the autonomic pathway that originates in the CNS.

Postganglionic Neuron

The second neuron in the autonomic pathway that synapses with a preganglionic neuron.

Dual Innervation

Most visceral organs receive nerve fibers from both the sympathetic and parasympathetic divisions.

Cholinergic Receptors

Receptors that bind acetylcholine, including nicotinic and muscarinic types.

Adrenergic Receptors

Receptors that bind norepinephrine, classified as alpha (α) and beta (β) receptors.

Autonomic Ganglion

Clusters of neurons located outside the CNS where preganglionic neurons synapse with postganglionic neurons.

Craniosacral Division

Another name for the parasympathetic division, reflecting its anatomical origins.

Thoracolumbar Division

Another name for the sympathetic division, as it originates in the thoracic and lumbar regions.

Visceral Reflex Arc

A reflex pathway involving two consecutive neurons that operate outside of conscious control.

Sympathetic Tone

The baseline level of sympathetic nervous system activity that helps regulate blood vessel diameter and blood pressure.

Homeostasis

The maintenance of stable internal physiological conditions.

Higher Brain Centers

Regulate and coordinate the activities of the somatic and autonomic nervous systems.