The Peripheral Nervous System

These flashcards cover key vocabulary terms and definitions related to the Peripheral Nervous System, including cranial and spinal nerves, reflexes, and important functions of different nerve systems.

Peripheral Nervous System (PNS)

A part of the nervous system outside the brain and spinal cord, which includes spinal and cranial nerves.

Cranial Nerves

Twelve pairs of nerves arising from the brain, mostly from the brainstem, responsible for sensory and motor function.

Spinal Nerves

Thirty-one pairs of mixed nerves that arise from the spinal cord, numbered by their location on the vertebral column.

Dorsal Root Ganglion

A swelling in the dorsal root of spinal nerves containing the cell bodies of sensory neurons.

Cauda Equina

A bundle of spinal nerve roots that arise from the lower part of the spinal cord.

Plexuses

Complex networks formed by ventral rami of spinal nerves that redistribute nerve fibers.

Motor (Efferent) Division

The part of the nervous system that transmits motor commands from the CNS to effectors.

Sensory (Afferent) Division

The part of the nervous system that conveys sensory information from the body to the CNS.

Reflex Arc

The neural pathway that mediates a reflex action, consisting of a receptor, sensory neuron, integration center, motor neuron, and effector.

Somatic Nervous System

The component of the PNS associated with voluntary control of body movements via skeletal muscles.

Autonomic Nervous System (ANS)

The component of the PNS that controls involuntary functions, divided into sympathetic and parasympathetic divisions.

Dermatome

An area of skin that is primarily supplied by a single spinal nerve root.

Myotome

A group of muscles innervated by a specific spinal nerve root.

Phrenic Nerve

A nerve arising from the cervical plexus that innervates the diaphragm, essential for breathing.

Brachial Plexus

A network of nerves formed by the ventral rami of C5 to T1, innervating the shoulder, arm, and hand.

Lumbar Plexus

A network of nerves formed by the ventral rami of L1 to L4, supplying nerves to the lower limb.