Autonomic Nervous System Review: Sympathetic vs Parasympathetic (Key Terms)

Vocabulary flashcards covering key autonomic nervous system concepts from the lecture notes.

Sympathetic nervous system

Thoracolumbar division of the autonomic nervous system that prepares the body for stress (fight-or-flight) and can stimulate the adrenal medulla to release stress hormones.

Parasympathetic nervous system

Craniosacral division that promotes rest-and-digest functions, including pupil constriction and increased salivation.

Thoracolumbar division

The sympathetic division; arises from the thoracic and lumbar regions of the spinal cord.

Craniosacral division

The parasympathetic division; arises from the brainstem and sacral spinal cord.

Adrenal medulla

A modified sympathetic ganglion; stimulated by preganglionic sympathetic fibers to release epinephrine and norepinephrine into the bloodstream.

Dual innervation

Most viscera receive input from both sympathetic and parasympathetic divisions, typically with opposing or complementary effects.

Nicotinic receptor

Acetylcholine receptor at skeletal muscle (neuromuscular junction) and autonomic ganglia; binding produces rapid excitatory effects.

Beta-1 adrenergic receptor

Adrenergic receptor on the heart; norepinephrine binding increases heart rate and contractility.

Acetylcholine

Neurotransmitter used by parasympathetic preganglionic and postganglionic neurons; also at the neuromuscular junction; acts on nicotinic and muscarinic receptors.

Pupil constriction (miosis)

Parasympathetic effect causing the pupil to become smaller.

Airway relaxation (bronchodilation)

Sympathetic effect relaxing airway smooth muscle to widen airways during stress.

Fight or flight

Classic sympathetic response during emergencies, excitement, exercise, or embarrassment.