Lab Chap 16

Ventral Median Fissure

A deep groove running along the anterior side of the spinal cord that divides the spinal cord into left and right halves.

Cauda Equina

A bundle of nerve roots at the end of the spinal cord (L2-S5) that provides nerves to the lower limbs and pelvic organs.

Central Canal

A small canal running through the center of the spinal cord that contains cerebrospinal fluid (CSF).

Conus Medullaris

The tapered, lower end of the spinal cord around the L1-L2 vertebra that marks the end of the spinal cord.

Dorsal Root

Nerve fibers that carry sensory information to the spinal cord.

Dorsal Root Ganglion

A cluster of sensory nerve cell bodies located on the dorsal root.

Filum Terminale

A delicate fibrous thread extending from the conus medullaris to the coccyx that anchors the spinal cord in place.

Gray Matter

The inner, butterfly-shaped region of the spinal cord, composed of neuron cell bodies and synapses.

Lateral Horn

A section of the gray matter found in the thoracic and upper lumbar regions containing autonomic motor neurons.

Anterior Horn

The front portion of the gray matter found in all regions of the spinal cord containing motor neurons for voluntary skeletal muscles.

Posterior Horn

The back portion of the gray matter that processes sensory information entering the spinal cord.

Dorsal Median Sulcus

A shallow groove along the posterior side of the spinal cord that serves as a landmark.

Spinal Nerve

A mixed nerve formed from the joining of dorsal and ventral roots carrying both sensory and motor information.

Ventral Root

Nerve fibers that carry motor information away from the spinal cord.

White Matter

The outer region of the spinal cord, composed primarily of myelinated axons.

Lateral Funiculus

One of the three white matter columns containing ascending and descending tracts relaying sensory and motor information.

Anterior Funiculus

The white matter column on the front side of the spinal cord containing tracts for motor and sensory functions.

Posterior Funiculus

The white matter column on the back side of the spinal cord that carries sensory information to the brain.

Meninges

Three layers of connective tissue that cover and protect the spinal cord and brain.

Dura Mater

The outermost, thick layer of the meninges that provides a protective barrier for the spinal cord.

Arachnoid Mater

The middle layer of the meninges that acts as a cushioning layer.

Pia Mater

The innermost layer of the meninges that directly nourishes the spinal cord.

Plexuses

Networks of nerves formed by the merging of spinal nerve roots that distribute fibers to specific body regions.

Brachial Plexus

A network of nerves formed by the anterior rami of C5-T1 supplying upper limbs.

Cervical Plexus

A network of nerves formed by the anterior rami of C1-C4 supplying the neck and diaphragm.

Lumbar Plexus

A network of nerves formed by the anterior rami of L1-L4 supplying the lower abdomen and groin.

Sacral Plexus

A network of nerves formed by the anterior rami of L4-S4 supplying the buttocks and legs.

Axillary nerve; origin; innervates; motor/sensory action

Comes from Bracial plexus, innervates the deltoid; shoulder abductionprovides sensation to the skin overlying the shoulder.

Femoral Nerve; Origin; innervates; motor/sensory action

the lumbar plexus (L2-L4); innervates quadriceps; knee extension, sensation to the anterior and medial thigh.

Median nerve; origin; innervation; motor/sensory action

the brachial plexus (C5-T1); innervates flexor muscles in the forearm; wrist flexion, sensation to the skin of the lateral palm and fingers.

Radial nerve; origin; innervation; motor/sensory action

the brachial plexus (C5-T1); extensor muscles of the arm and forearm; elbow extension, sensation to the skin of the posterior arm and forearm.

Sciatic nerve; origin; innervation; motor/sensory action

the sacral plexus(L4-S3); innervates muscles in the posterior thigh and all muscles in the leg and foot; knee flexion, sensation to the skin of the posterior thigh, leg, and foot; Largest nerve in body

Tibial nerve; origin; innervation. motor/sensory action

the sacral plexus (L4-S3), branch of sciatic; innervates muscles of the posterior leg and foot; ankle plantar flexion, sensation to the skin of the sole of the foot.

ulnar nerve; origin; innervation; motor/sensory action

the brachial plexus (C8-T1); innervates flexor muscles of the forearm and intrinsic muscles of the hand; finger adduction and abduction, sensation to the skin of the medial hand.

Phrenic nerve; origin; innervation; motor/sensory action

the cervical plexus (C3-C5); innervates the diaphragm; responsible for breathing and sensation to the central diaphragm.

Brachial plexus origin and location

The brachial plexus originates from spinal nerves C5-T1, located in the neck region and extending into the axilla. It is responsible for innervating the upper limb.

Cervical plexus origin and location

The cervical plexus originates from spinal nerves C1-C4, located in the neck region. It is responsible for innervating muscles and skin in the neck and parts of the shoulder.

Lumbar plexus origin and location

The lumbar plexus originates from spinal nerves L1-L4, located in the lower back region. It is responsible for innervating the lower limb and parts of the pelvis.

Sacral plexus origin and location

originates from spinal nerves L4-S4, located in the pelvic region. It innervates the lower limb, pelvic structures, and perineum.

Always Fight Menacing Rogues So Truth Unites Peacefully

Axillary, Femoral, Median, Radial, Sciatic, Tibial, Ulnar, Phrenic

Clark Beats Luthor Smoothly Cool!

Cervical, Brachial, Lumbar, Sacral, coccygeal

somatic reflex arch

Reflex pathway involving sensory neurons, interneurons, and motor neurons, responsible for voluntary muscle movement in response to stimuli. It includes the spinal cord and is typically a rapid response to avoid injury.

Somatic reflex receptor; description; function

A sensory structure that detects changes in the environment, converting stimuli into nerve impulses. It plays a crucial role in initiating somatic reflexes by informing the nervous system of various stimuli.