Nervous System: Autonomic Nervous System Anatomy & Physiology

A set of flashcards designed to cover key concepts related to the autonomic nervous system, its anatomy, physiology, and functional organization.

Somatic Nervous System (SNS)

The part of the nervous system that controls voluntary movements and consciously perceived processes, including motor signals to skeletal muscles.

Autonomic Nervous System (ANS)

Also known as the autonomic motor or visceral motor system, it regulates processes below the conscious level, affecting the heart, smooth muscle, and glands.

Preganglionic Neuron

A neuron that extends from the CNS to an autonomic ganglion, releasing acetylcholine to stimulate the ganglionic neuron.

Ganglionic Neuron

A neuron located in an autonomic ganglion that relays motor output from the preganglionic neuron to the effector.

Sympathetic Division

Part of the ANS responsible for the 'fight-or-flight' response; increases alertness and metabolic activity.

Parasympathetic Division

Part of the ANS responsible for 'rest-and-digest' functions; conserves energy and replenishes nutrient stores.

Dual Innervation

The condition where an organ receives input from both the sympathetic and parasympathetic divisions of the ANS.

Cholinergic Neurons

Neurons that release acetylcholine (ACh) as their neurotransmitter, including all ANS preganglionic neurons.

Adrenergic Neurons

Neurons that release norepinephrine (NE) as their neurotransmitter, predominantly in the sympathetic division.

Autonomic Reflex

A pre-programmed response to a stimulus involving autonomic effectors such as cardiac or smooth muscle.

Homeostasis

The process by which the ANS maintains a stable internal environment in response to changes.

Neuronal Convergence

The phenomenon where multiple preganglionic neurons synapse on one ganglionic neuron.

Neuronal Divergence

The branching of axons from one preganglionic neuron synapsing with numerous ganglionic neurons.

Nicotinic Receptors

Cholinergic receptors found on all ganglionic neurons and adrenal medulla cells; stimulate excitation upon binding acetylcholine.

Muscarinic Receptors

Cholinergic receptors found in target organs of the parasympathetic division; can have varied effects depending on the subtype.

Epinephrine

A hormone released by the adrenal medulla during sympathetic activation; enhances and prolongs the fight-or-flight response.

Vagal Tone

The constant activity of the vagus nerve; influences heart rate by promoting parasympathetic activity.

Autonomic Plexuses

Networks of nerves containing sympathetic postganglionic axons, parasympathetic preganglionic axons, and visceral sensory axons.

Raynaud Syndrome

A condition characterized by sudden constriction of small arteries in digits, resulting in blanching and pain, commonly triggered by cold or stress.