a&p ch 13 video notes

conduction

nerve fibers conduct information up (ascending) and down (descending) spinal cord

sensory

ascending tracts or sensory or motor?

motor

descending tracts are sensory or motor?

neural integration

neurons receive input from sources, integrates it, and decides appropriate output

locomotion

groups of neurons that coordinate repetitive sequences of contractions for walking

reflexes

involuntary responses to stimuli

flattened cylinder

arises from the brainstem; extends from foramen magnum to L1-L2; growth of cord stops at age 5; gives rise to 31 pairs of spinal nerves

meninges

three fibrous membranes that enclose the brain and spinal cord

epidural space

what is the space above the meninges

spina bifida

congenital defect; one or more vertebrae fail to completely enclose spinal cord; lack of folic acid increases risk

lateral horn

contains neurons of sympathetic nervous system (T2-L1)

myelinated axons

white matter is what

spinal tracts

fibers in a given tract have similar origin, destination, and function

ascending tracts

carry sensory signals up the spinal cord

first neuron

detect stimulus and transmit signals to spinal cord or brainstem

second neuron

from spinal cord/brainstem continues to the thalamus

third neuron

carries the signal the rest of the way to the sensory region of the cerebral cortex

descending tracts

carry motor signals down the brainstem and spinal cord; involve two motor neuron; upper and lower motor neurons; decussation of lower neurons cross in medulla oblongata

poliomyelitis

caused by the poliovirus; destroys motor neurons in brainstem and anterior horns of spinal cord

ALS

destruction of motor neurons and muscular atrophy; sclerosis of lateral regions of the spinal cord; astrocytes fail to reabsorb the neurotransmitter glutamate from the tissue fluid

nerve

a cord-like organ composed of numerous nerve fiber (axons) bound together by connective tissue

endoneurium

wrapping external to neurilemma

perineurium

surrounds each fascicles bundles of nerve fibers

epineurium

covering of entire nerve

ganglion

cluster of neurosomas outside the CNS

posterior root ganglion

contains the soma of sensory neurons; enter posterior horn of cord

anterior ramus

in thoracic region it gives rise to intercostal nerve; in other regions, anterior rami from plexuses

posterior ramus

innervates the muscles and joints in that region of the spine and the skin of the back

chickenpox

common disease of early childhood; caused by varicella zoster virus

shingles

common after age 50; virus travels down the sensory nerves when immune system is compromised

somasensory function

carry sensory signals from bones, joints, muscles, and skin

proprioception

brain get information about body position and movements from muscles, tendons, and joints

motor function

primarily to stimulate muscle contraction

cervical plexus

supply muscles of the shoulder and neck

brachial plexus

innervates the upper limb and some of shoulder and neck

lumbar plexus

innervates the buttock and lower limb

sciatica

sharp pain that travels from gluteal region along the posterior side of the thigh and leg to the ankle