Introduction to the Autonomic Nervous System

Flashcards covering the fundamental structure, function, and signaling of the autonomic nervous system.

Autonomic nervous system (ANS)

The system that regulates involuntary body functions and internal organs, serving as a critical component in clinical patient assessment.

Two-neuron chain

The basic autonomic pathway consisting of two neurons that connect the central nervous system to an effector organ.

Ganglion

The relay point in the autonomic pathway where the two neurons in the sequence synapse.

Information flow (Central Autonomic)

The movement of signals within control areas, characterized by incoming sensory signals versus outgoing autonomic commands.

Sympathetic system origin

The region where sympathetic fibers originate, specifically the thoracolumbar portion of the spinal cord.

Parasympathetic system origin

The region where parasympathetic fibers originate, specifically the craniosacral portion of the nervous system.

Sympathetic ganglia location

Located near the spinal cord, resulting in short pre-ganglionic fibers and long post-ganglionic fibers.

Parasympathetic ganglia location

Located near or within the target organ, resulting in long pre-ganglionic fibers and short post-ganglionic fibers.

Adrenergic receptor family

A group of receptors consisting of alpha ($\alpha$) and beta ($\beta$) subtypes that mediate sympathetic responses based on their location and typical physiologic effect.

Cholinergic receptor family

A group of receptors consisting of muscarinic and nicotinic subtypes that respond to acetylcholine.

Acetylcholine (ACh) termination

The "off switch" for acetylcholine signaling, which involves enzymatic degradation to determine the duration and intensity of effects.

Norepinephrine (NE) termination

The "off switch" for norepinephrine signaling, primarily achieved through reuptake rather than enzymatic destruction.

Adrenal medulla

A structure that amplifies sympathetic responses by releasing epinephrine and norepinephrine into the bloodstream for systemic, body-wide effects.