Human Anatomy Mike Aaron Ch 14

Spinal Cord

connection between the brain and the body

connective coverings around the spinal cord

the Vertebral Column & the Spinal Meninges

Vertebral Column

composed of bone tissue and protects the cord ; spinal cord is located in the vertebral foramen

Spinal Meninges

Dura Mater, Arachnoid Layer, Pia Mater

Dura Mater in Spinal Cord

has Denticulate Ligaments that fuse with the arachnoid layer and hold the spinal cord in place

2 enlargements on the Spinal Cord

Cervical Enlargement & Lumbar Enlargement

Cervical Enlargement

in the neck ; nerves to/from the arms

Lumbar Enlargement

in the lower back ; nerves to/from the legs

Conus Medullaris

tapered cone shaped end of the spinal cord ; composed of the Filum Terminale & Cauda Equina

Filum Terminale

extension of the Pia Mater ; attaches spinal cord to coccyx and holds cord in place

Cauda Equina

collection of nerves extending from the Conus Medullaris ; extends into the pelvic region and into the legs

Gray Matter of the Spinal Cord

shaped like a butterfly ; made of Gray Commissure, Central Canal, and Horns

Gray Commissure

forms the body of the butterfly

Central Canal

small space extending the entire length of the spinal cord containing CSF

Horns

Posterior & Anterior horns dividing the sides of gray matter

Posterior Horn

motor neurons to cardiac & smooth muscle and glands

Anterior Horn

motor neurons to skeletal muscles

White Matter of the Spinal Cord

surrounds the gray matter ; divided into anterior, posterior, & lateral horns ; contains White Commissure and Tracts

White Commissure

connects the white matter of the right and left sides of the spinal cord together

Tracts

bundles of nerves associated with white matter ; Ascending & Descending

Ascending Tracts

to brain

Descending Tracts

to body

Spinoreticular Tracts

ascending ; carry impulses for pain to the brain

Gracile Fasciculus Tracts

ascending ; carry impulses for touch, pressure, vibration, & awareness of body position to the brain

Anterior Corticospinal Tracts

descending ; carry impulses from the brain to skeletal muscles

Lateral Vestibulospinal Tracts

carry impulses from the brain to receptors in the body that regulate muscle tone, posture, and coordination

Spinal Nerves

31 pairs connecting the CNS with the nerves of the PNS ;

Anterior & Posterior Roots

2 points of attachment on the spinal cord for each nerve

Anterior Root

motor neurons

Posterior Root

sensory neurons

Fascicles

nerve fibers organized into bundles

Connective Coverings around Nerves

Epineurium, Perineurium, Endoneurium

Epineurium

surrounds and protects entire nerve

Perineurium

surrounds bundles of nerve fibers (fascicles)

Endoneurium

surrounds individual nerve fibers

2 types of Reflexes

Somatic and Autonomic

Reflex Arcs

pathways traveled by reflexes

components of a Reflex Arc

Receptor, Sensory Neuron, Integration Center, Motor Neuron, Effector

the Receptor

site of stimulus action

Sensory Neuron

detects the stimulation and sends impulses to the spinal cord and brain

Integration Center

makes decisions relating to the reflex

Motor Neuron

conducts impulses from the integrating center to the muscles and glands of the body

Effector

the muscle or gland that responds to the impulses from the motor neuron

Patellar Reflex

knee extension ; indicated nerve damage in Lumbar region

Achilles Reflex

extension of big toe ; lacking in diabetics and alcoholics

Babinski Sign

extension of great toe with fanning of other toes in babies ; becomes Plantar Flexion in adults

Flexor Reflex

contraction of flexor muscles in the hand resulting in withdrawal of a limb from a pain stimulus

Crossed Extension Reflex

contraction of extensor muscles in one limb while flexor muscles of the opposite limb contract

Tendon Reflex

inhibition of a muscle contraction when a tendon is excessively stretched

Paralysis

loss of motor function associated with severe trauma to the spinal cord ; paraplegia, quadriplegia, and hemiplegia

Paraplegia

loss of the use of lower limbs ; usually a result of damage to lumbar portion of spinal cord

Quadriplegia

all 4 limbs affected ; result of damage to cervical region of spinal cord

Hemiplegia

paralysis on one side of the body ; usually a result of a brain injury

Amyotrophic Lateral Sclerosis (ALS)

destruction of Anterior Horns of the spinal cord

Poliomyelitis

viral infection

Myelitis

inflammation of a nerve

Guillian-Barre Syndrome

strips myelin from nerves ; usually triggered by a viral infection

Shingles

caused by Varicella zoster (chicken pox) ; severe painful rash develops along major sensory nerves

Neuralgia

pain along nerve length

Parashesia

abnormal sensations (tingling, burning) in the absence of actual stimulation

Peripheral Neuropathy

loss of sensory or motor function due to nerve injury

Spinal Meningitis

inflammation of spinal meninges due to a viral or bacterial infection