Nerve Plexuses and Reflex Arcs

These flashcards cover key vocabulary from the lecture notes on nerve plexuses and the mechanisms of reflex actions.

Nerve Plexus

A network of nerves originating from ventral rami of spinal nerves.

Cervical Plexus

A nerve plexus formed by spinal nerves C1-C4, responsible for innervating neck muscles and the diaphragm.

Brachial Plexus

A plexus formed from spinal nerves C5-T1 that innervates the pectoral girdle and upper limb.

Lumbar Plexus

Composed of ventral rami from T12-L4, innervating the muscles and skin of the lower abdomen and anterior thigh.

Sacral Plexus

Formed by ventral rami from L4-S4, it innervates muscles of the pelvis and lower limbs.

Dermatome

A specific region of skin supplied by sensory fibers of a single spinal nerve root.

Reflex Arc

The pathway of a reflex, beginning with a sensory receptor and ending with a peripheral effector.

Stretch Reflex

A muscle contraction in response to stretching within the muscle.

Patellar Reflex

A stretch reflex that occurs when the patellar tendon is tapped, causing contraction of the quadriceps.

Conus Medullaris

The tapered end of the spinal cord, approximately at the L1-L2 vertebrae.