A&P 1 - Module 10 (Spinal Cord, Spinal Nerves, & Reflexes)

Cervical Region (of the spinal cord)

The uppermost section of the spinal cord, located within the first seven vertebrae (C1-C7), responsible for movement and sensation in the neck, shoulders, arms, and upper torso.

Thoracic Region (of the spinal cord)

The middle section of the spinal cord, located within twelve vertebrae (T1-T12), responsible for movement and sensation of the chest and upper abdomen.

Lumbar Region (of the spinal cord)

The lower section of the spinal cord, located within five vertebrae (L1-L5), responsible for movement and sensation of the lower back, hips, and legs.

Sacral Region (of the spinal cord)

The collection of spinal nerves associated with the sacrum (vertebrae S1-S5), responsible for movement and sensation of the pelvis, lower limbs, and autonomic functions.

Coccygeal Region (of the spinal cord)

The collection of spinal nerves associated with the coccyx (vetebrae Co1), responsible for sensation of the coccyx (tailbone).

Conus Medullaris

The tapered, cone-shaped end of the spinal cord, located near the first or second lumbar vertebra (L1, L2).

Cauda Equina

A bundle of spinal nerves extending inferiorly from the conus medullaris that resembles a horse's tail (cauda, tail; equina, horse).

White Matter

The area of the spinal cord or brain consisting of myelinated axons.

Gray Matter

The area of the spinal cord or brain containing neuron cell bodies, dendrites, and unmyelinated axons.

Central Canal (of the spinal cord)

A small, cerebrospinal fluid-filled channel that runs through the center of the spinal cord.

Posterior Median Sulcus

A shallow groove along the posterior (dorsal) midline of the spinal cord that helps divide the cord into right and left halves.

Anterior Median Fissure

A deep groove along the anterior (ventral) midline of the spinal cord, separating the left and right halves.

Anterior Root

The efferent nerve fibers connected to the anterior portion of the spinal cord that transport motor signals.

Posterior Root

The afferent nerve fibers connected to the posterior portion of the spinal cord that transport sensory signals.

Posterior Root Ganglion

A group of sensory neuron cell bodies located on the posterior root.

Spinal Nerve

A mixed nerve formed by the union of the anterior and posterior roots, responsible for transmitting motor, sensory, and autonomic signals between the spinal cord and the body.

Pia Mater

The deepest layer of the meninges; a thin, delicate membrane that directly covers and protects the spinal cord and brain.

Arachnoid Mater

The middle layer of the meninges; a web-like membrane that helps cushion the spinal cord and brain.

Dura Mater

The superficial layer of the meninges; a tough, outer membrane that provides structural support and protection for the spinal cord and brain.

Subarachnoid Space

The space between the arachnoid mater and pia mater that transports cerebrospinal fluid around the spinal cord and brain and provides cushioning.

Epidural Space

The space between the dura mater and the vertebral column, containing fat and blood vessels, and commonly used for anesthesia administration.

Lumbar Puncture

A medical procedure in which a needle is inserted into the subarachnoid space in the lower lumbar region to collect cerebrospinal fluid for diagnostic testing.

Epineurium

The superficial connective tissue layer surrounding an entire peripheral nerve, providing protection and structural integrity.

Perineurium

The connective tissue layer that surrounds a bundle (fascicle) of nerve fibers within a peripheral nerve.

Endoneurium

The delicate connective tissue layer that surrounds individual nerve fibers within a fascicle.

Posterior Ramus

The branch of a spinal nerve that innervates the muscles and skin of the back.

Anterior Ramus

The branch of a spinal nerve that innervates the muscles and skin of the limbs (arms, legs) and lateral and anterior trunk.

Rami Communicantes

The branches of a spinal nerve that innervate visceral organs, facilitating autonomic functions.

Dermatome

A specific area of skin supplied by sensory fibers from a single spinal nerve.

Innate Reflex

A reflex that is present at birth.

Acquired Reflex

A reflex that develops over time through experience and repetition.

Somatic Reflex

A reflex that includes an effector made of skeletal muscle.

Visceral Reflex

A reflex that includes an effector made of non-skeletal muscle tissue (i.e., smooth muscle, cardiac muscle, or glands).

Monosynaptic

A reflex involving only one synapse between a sensory neuron and a motor neuron, allowing for a rapid response.

Polysynaptic

A reflex involving one or more interneurons between the sensory and motor neurons, allowing for more complex reflex responses.

Spinal Reflex

A reflex that is processed within the spinal cord without direct involvement of the brain.

Cranial Reflex

A reflex that is processed within the brainstem rather than the spinal cord.