Autonomic Nervous System (ANS) – Lecture Vocabulary

A comprehensive set of vocabulary flashcards covering the major structures, pathways, neurotransmitters, and clinical correlations of the autonomic nervous system as presented in the lecture.

Autonomic Nervous System (ANS)

Motor branch of the nervous system that automatically regulates smooth muscle, cardiac muscle, and glands through sympathetic and parasympathetic divisions.

Somatic Nervous System

Motor branch that consciously controls skeletal muscles and carries sensory input from exteroceptors.

Sympathetic Division

Thoracolumbar branch of the ANS that produces the fight-or-flight response, maximizing oxygen delivery to skeletal muscle.

Parasympathetic Division

Craniosacral branch of the ANS that produces the rest-and-digest response, promoting routine body maintenance like digestion and urination.

Enteric Nervous System

Intrinsic network of neurons within the GI tract that can function independently of the CNS to control digestion.

Preganglionic Neuron

First motor neuron in an ANS pathway; cell body in the CNS, axon synapses in an autonomic ganglion.

Postganglionic Neuron

Second motor neuron in an ANS pathway; cell body in an autonomic ganglion, axon projects to the effector organ.

Ganglion

Collection of neuronal cell bodies located outside the central nervous system.

Ciliary Ganglion

Parasympathetic ganglion in the orbit that controls constriction and dilation of the pupil.

Pterygopalatine Ganglion

Parasympathetic ganglion near the palate that innervates glands of the nasal cavity and palate.

Otic Ganglion

Parasympathetic ganglion just inferior to the ear that supplies the parotid salivary gland.

Fight-or-Flight Response

Physiological changes driven by sympathetic activation to prepare the body for emergency action.

Rest-and-Digest Response

Physiological state produced by parasympathetic activity that conserves energy and supports housekeeping functions.

Thoracolumbar Outflow

Origin of sympathetic preganglionic neurons in T1–L2 spinal cord segments.

Craniosacral Outflow

Origin of parasympathetic preganglionic neurons in cranial nerves III, VII, IX, X and sacral spinal cord (S2–S4).

Sympathetic Trunk Ganglia

Chain of paired ganglia running lateral to the vertebral column that houses many sympathetic postganglionic cell bodies.

Prevertebral Ganglia

Sympathetic ganglia located anterior to the vertebral column near major abdominal arteries.

Plexus

Network of autonomic nerves often surrounding blood vessels, mixing sympathetic and parasympathetic fibers.

Solar (Celiac) Plexus

Large autonomic plexus just below the diaphragm that supplies abdominal organs.

Superior Mesenteric Plexus

Autonomic plexus associated with the superior mesenteric artery, supplying most of the small intestine.

Inferior Mesenteric Plexus

Autonomic plexus around the inferior mesenteric artery, supplying the large intestine and rectum.

Renal Plexus

Autonomic plexus surrounding each kidney, regulating renal blood flow and urine formation.

Hypogastric Plexus

Autonomic plexus in the pelvis that innervates pelvic organs and genitalia.

Splanchnic Nerves

Parasympathetic nerves arising from the sacral spinal cord that supply pelvic organs.

Cholinergic Receptor

Receptor that binds acetylcholine; divided into nicotinic and muscarinic types.

Nicotinic Receptor

Fast cholinergic receptor (also activated by nicotine) located on all autonomic ganglia and skeletal muscle end plates.

Muscarinic Receptor

Slow cholinergic receptor located on parasympathetic effector organs and some sympathetic sweat glands.

Adrenergic Receptor

Receptor that binds norepinephrine or epinephrine; subdivided into alpha and beta types.

Acetylcholine (ACh)

Primary neurotransmitter released by all preganglionic neurons and parasympathetic postganglionic neurons.

Norepinephrine (NE)

Neurotransmitter released by most sympathetic postganglionic neurons and the adrenal medulla.

Reflex Arc

Neural pathway consisting of receptor, sensory neuron, integration center, motor neuron, and effector, used by autonomic reflexes.

Autonomic Dysreflexia

General term for abnormal or exaggerated autonomic responses to stimuli, often after spinal cord injury.

Asthma (as Dysreflexia)

Example of autonomic dysreflexia where bronchial smooth muscle constricts instead of dilating, limiting airflow.

Raynaud’s Disease

Peripheral autonomic disorder causing excessive vasoconstriction or dilation, leading to color changes and pain in extremities.