Autonomic Nervous System Overview

A collection of key terms and definitions related to the autonomic nervous system for review.

Autonomic Nervous System

The system controlling visceral motor neurons, divided into sympathetic and parasympathetic divisions.

Sympathetic Division

Part of the autonomic nervous system responsible for the 'fight or flight' response.

Parasympathetic Division

Part of the autonomic nervous system responsible for 'rest and digest' functions.

Preganglionic Neurons

Neurons that arise from the CNS and synapse in autonomic ganglia before reaching their target organ.

Postganglionic Neurons

Neurons that receive signals from preganglionic neurons and innervate the target organs.

Ganglia

Clusters of neuron cell bodies located in the PNS.

Acetylcholine (ACh)

A neurotransmitter used by preganglionic neurons in both sympathetic and parasympathetic systems.

Epinephrine

A neurotransmitter released by postganglionic sympathetic neurons, also known as adrenaline.

Neuronal Divergence

The phenomenon where one preganglionic neuron can synapse with multiple postganglionic neurons.

Nicotinic Receptors

Receptors that bind acetylcholine in the autonomic ganglia, stimulating postganglionic neurons.

Muscarinic Receptors

Receptors found on target organs of the parasympathetic nervous system that respond to acetylcholine.

Adrenergic Receptors

Receptors in the sympathetic nervous system that bind epinephrine and norepinephrine.

Thoracolumbar Division

Anatomical term for the sympathetic nervous system due to its location from T1 to L2 spinal segments.

Craniosacral Division

Anatomical term for the parasympathetic nervous system due to its origin in the cranial and sacral regions.

Varicosities

Swelling along the axons of postganglionic neurons that release neurotransmitters.

Homeostasis

The maintenance of stable internal conditions in the body as managed by the autonomic nervous system.

Collateral Ganglia

Ganglia located in the abdomen and pelvis that innervate organs in those regions.

Suprarenal Medulla

The inner part of the adrenal gland that secretes adrenaline directly into the bloodstream.

Dorsal and Ventral Rami

Branches of spinal nerves that contain both sensory and motor fibers.

Splachnic Nerves

Nerves containing autonomic fibers that innervate abdominal and pelvic organs.