Spinal Cord and Peripheral Nervous System (Vocabulary Flashcards)

Vocabulary flashcards covering key terms about the spinal cord and peripheral nervous system.

Spinal cord

An oval-shaped hollow cylinder of nervous tissue that runs from the brainstem to the lower back; protected by the vertebral column; gives rise to 31 pairs of spinal nerves.

Dorsal root

Carries sensory (afferent) neurons into the spinal cord.

Ventral root

Carries motor (efferent) neurons out of the spinal cord to muscles.

Mixed nerves

Nerves that contain both sensory and motor fibers; all spinal nerves are mixed.

Central nervous system (CNS)

The brain and spinal cord; the main control center of the nervous system.

White matter

Myelinated nerve fibers that transmit signals within the CNS.

Gray matter

Contains nerve cell bodies and non-myelinated fibers; in the spinal cord forms the butterfly-shaped region; in the brain forms the outer cortex.

Butterfly-shaped gray matter

The H-shaped region of gray matter in a spinal cord cross-section.

Peripheral nervous system (PNS)

Nerves that link the CNS to the rest of the body; includes cranial and spinal nerves.

Cranial nerves

12 pairs of nerves arising from the brain; can be sensory, motor, or mixed.

Spinal nerves

31 pairs of nerves arising from the spinal cord; all are mixed nerves.

Somatic nervous system

Part of the PNS that connects CNS to skin and skeletal muscles; governs voluntary movements.

Autonomic nervous system

Part of the PNS that connects CNS to visceral organs; regulates unconscious functions; divided into sympathetic and parasympathetic.

Sympathetic nervous system

Division of the ANS; consists of spinal nerves; prepares the body for emergencies (fight or flight).

Parasympathetic nervous system

Division of the ANS; includes some cranial and spinal nerves; returns the body to normal after sympathetic stimulation.

Flight or fight response

Physiological activation mediated by the sympathetic system in emergencies.

Rest and digest

Parasympathetic activities that promote relaxation and normal functioning after stress.