Parasympathetic Nervous System: Crash Course Anatomy & Physiology #15

Parasympathetic Nervous System

The calming side of the autonomic nervous system, responsible for regulating bodily functions when at rest.

Sympathetic Nervous System

The part of the autonomic nervous system that prepares the body for stressful or emergency situations.

Homeostasis

The balance maintained by the body systems to keep internal conditions stable.

Vagus Nerve

Cranial nerve that carries sensory information from the peripheral system to the brain and motor instructions from the brain to the body; has both sensory and motor functions.

Cranial Nerves

Twelve pairs of nerves that emerge directly from the brain; some control motor and voluntary functions, while others handle sensory information.

Acetylcholine (ACh)

A neurotransmitter used in both the sympathetic and parasympathetic nervous systems to facilitate communication between neurons.

Norepinephrine (NE)

A neurotransmitter primarily involved in the sympathetic nervous system, affecting bodily reactions during stress.

Ganglia

Clusters of nerve cell bodies located in the autonomic nervous system; sympathetic ganglia are near the spinal cord, while parasympathetic ganglia are close to the effectors.

Cardiac Muscle

Muscle tissue of the heart that is controlled by the autonomic nervous system.

Sympathetic Tone

The rate of action potentials traveling through the sympathetic nervous system, influencing bodily responses.

Parasympathetic Tone

The rate of action potentials traveling through the parasympathetic nervous system, usually dominant to maintain balance and calm.

Olfactory Nerve

The first cranial nerve responsible for the sense of smell.

Optic Nerve

The second cranial nerve responsible for vision.

Oculomotor Nerve

The third cranial nerve that controls most of the eye's movements.

Trigeminal Nerve

The largest cranial nerve, responsible for facial sensation and motor functions like biting and chewing.

Facial Nerve

The seventh cranial nerve that controls the muscles of facial expression.

Glossopharyngeal Nerve

The ninth cranial nerve that innervates the tongue and pharynx.

Spinal Accessory Nerve

The eleventh cranial nerve responsible for shoulder and head movement.

Hypoglossal Nerve

The twelfth cranial nerve that controls tongue movements for speech and swallowing.

Sympathetic and Parasympathetic Balance

The state where both the sympathetic and parasympathetic systems work together to regulate bodily functions.