Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
102 Cards in this Set
- Front
- Back
SPINAL CORDFUNCTIONS |
conduction
locomotion central pattern generators reflexes |
|
conduction
|
conduct information up and down the cord
|
|
locomotion
|
repetitive, coordinated contractions of muscles of thelimbs initiate walking
|
|
central pattern generators
|
groups of neurons causing the alternating movements of the leg muscles
|
|
reflexes
|
involuntary, stereotyped responses involving the brain,spinal cord and peripheral nerves
|
|
Terminology PNS
|
1. ganglia
2. nerves 3. spinal 4. cranial |
|
ganglia
|
collection of neuron cell bodies
|
|
Nerves
|
bundles of axons
|
|
spinal nerves
|
connected to the spinal cord
|
|
cranial nerves
|
connected to the brain
|
|
TerminologyCNS
|
8. motor (descending) pathway
7. sensory (ascending) pathway 6. columns 5. tracts 4. higher centers 3. neural cortex 2. nucleus 1. center |
|
spinal cord
|
cylinder of nervous tissue passing through the vertebralcolumn, beginning at the foramen magnum and ending at L1
-includes 31 pairs of spinal nerves that pass throughintervertebral foramina - has valley-likeindentations running along the midline called the posterior median sulcus andanterior median fissure -divided into cervical,thoracic, lumbar, and sacral regions - quantity of gray matter increases in areas involved withsensory and motor control of limbs |
|
posterior median sulcus
|
midline |
|
anterior medianfissure
|
midline |
|
Cervical enlargement
|
supplies nerves of the upper limbs
|
|
Lumbar enlargement
|
supplies nerves of the pelvic region and lower limbs
|
|
conus medullaris
|
tapered point at the terminal end of the spinalcord
|
|
cauda equina
|
“horse tail” bundle of nerve roots from L2 to S5
|
|
3 layers of spinal meninges
(fibrous connective tissues that separate the soft tissue ofthe CNS from the bones) |
Dura Mater Arachnoid Mater Pia Mater |
|
Dura mater
|
tough collagenous membrane forms a loose fittingsleeve called a “dural sheath” around the spinal cord
|
|
epidural space
|
superficial to dura mater, filled with adiposeand blood vessels
|
|
epidural block |
affects the area immediately around the site ofinjection |
|
arachnoid mater
|
layer of simple squamous epitheliumthat adheres to the dura mater, creates a mesh of collagenous and elasticfibers spanning a gap
|
|
Subarachnoid space
|
a gap spanningof collagenous and elastic fibers filled with cerebral spinal fluid (CSF)
|
|
pia mater
|
delicate, translucent membranedirectly adhering to the spinal cord
|
|
terminal filum
|
fibrous extension of the pia mater that anchorsthe spinal cord to the coccyx
|
|
denticulate ligaments
|
extend from pia mater through arachnoid materand attach to dura mater, prevent side to side movement
|
|
Meningitis
|
inflammation of the meninges, possibly due to infection by abacteria or virus
|
|
Lumbar puncture (spinal tap)
|
withdrawal of CSF from the lumber region, to avoid injury tothe spinal cord, cloudiness may indicate bacterial infection
|
|
graymatter
|
contains the somas, dendrites and proximal partsof the axons of neurons, it is the site of synaptic contact between neurons andprocesses information
|
|
white matter
|
contains bundles of axons, called tracts that carry signals from one part of CNS to another
|
|
Gray Matter
|
shaped like a butterfly in the spinal cord
composed of: Dorsal (posterior)gray horns Ventral (anterior)gray horns lateral gray horns(from T2-L1)
gray commissure
|
|
Dorsal (posterior) gray horns
|
receive somatic and visceral sensoryinformation from dorsal root
|
|
Ventral (anterior) gray horns
|
contain somas of somatic motorneurons with axons exiting the ventralroot
|
|
lateral gray horns(from T2-L1)
|
contain visceral motorneurons of the sympathetic nervous system
|
|
gray commissure
|
how the horns are connected
|
|
White Matter
|
- axon bundles arranged in 3 pairs called columns (funiculi)
1) dorsal (posterior) white column 2) ventral (anterior) white column 3) lateral white column -column divided into tracts (fasciculi) *ascending tracts * descending tracts |
|
ascending tracts
|
carry sensoryinformation toward the brain |
|
descending tracts |
carry motorinformation from the brain |
|
spinal nerves
|
includes 31 pairs of nerves along the vertebral column, 8cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal
|
|
nerve
|
a cord composed of many nerve fibers (axons) bound togetherby connective tissue, contains from a few to millions of nerve fibers
|
|
epineurium |
dense irregular connective tissue surrounding abundle of fascicles, protects the nerve from stretching and injury |
|
fascicle |
a bundle of nerve fibers |
|
perineurium |
connective tissue surrounding a fascicle |
|
Endoneurium |
loose connective tissue surrounding an individual nervefiber |
|
dermatome |
a region of skin monitored by a spinal nerve,each has a 50% overlap with adjacent regions |
|
peripheral neuropathies |
losses of sensory or motor function from nervedamage |
|
Shingles |
caused by the chickenpox virus (Varicella-Zoster Virus),after you get chickenpox, the virus hides in your dorsal root ganglia and mayreemerge later in life as shingles- symptoms include rash and blisters along a dermatomewith intense itching and sometimes post-herpeticneuralgia or nerve pain |
|
post-herpetic neuralgia |
nerve pain |
|
dorsalroot |
divides into 6-8 nerve rootletsthat enter the spinal cord -includes a swellingcalled the dorsal root ganglionwhich contains somas |
|
dorsal root ganglion |
a swelling which contains somas |
|
ventral root (motor) |
6-8 rootlets formconverge from the spinal cord |
|
Distal Branches |
once the nerve exits the vertebral columnthrough the intervertebral foramen, the nerve divides into 3 branches:
1)dorsal ramus 2) ventral ramus (sensory and motor -mixed)
3)rami communicantes (motor- sympathetic) |
|
cervical Plexus
|
innervates skin of the neck andswallowing muscles , most importantly the phrenic nerves |
|
phrenic nerves |
innervate the diaphragm and aid in breathing, ifirritated causes hiccups |
|
brachial Plexus |
innervates the upper limb and some muscles of the neck and lower shoulder |
|
axillary nerve |
deltoid and skin of shoulder |
|
musculocutaneous nerve |
biceps brachii and skin of lateral forearm |
|
median nerve |
flexors of forearm and skin ofanterolateral hand; if injured like when wrist slashing, makes it hard to use the pincer grasps |
|
Ulnar nerve |
flexor digitorum profundus andmedial surface of hand; injury would hinder your ability to make a fist,stimulates “funny bone” |
|
radialnerve |
extensor muscles of arm and forearmand skin of posterolateral limb; may be injured by improper crutch use, causeswrist drop a chronic flexing of the fingers, hand and wrist |
|
Lumbar Plexus |
lower back |
|
femoral nerve |
quadriceps and skin of anteromedial thigh |
|
Sacral Plexus |
around sacrum |
|
sciatic nerve |
composed of the tibial and common fibular nerves traveling together; controls muscles and skinof the back thigh and whole leg; most vulnerable nerve in the body **trauma causes sciatica,a sharp pain running from the gluteal area down the leg |
|
Coccygeal Plexus |
lower sacrum and coccyx |
|
neural pool |
1,000’s or millions of interneurons assembled together inone particular function, like controlling the beating of your heart orregulating your sense of hunger- information arrives at a neural pool through one or moreinput neurons, forming multiple synapses with the same postsynaptic cell |
|
discharge zone |
the area of a neural pool in which the input neuron can cause an action potential |
|
facilitated zone |
- the area outside of the discharge zone in aneural pool in which the input neuron can not cause an action potential, UNLESSaided by other input neurons |
|
neural circuit |
the pathways of the neurons that make up aneural pool |
|
Divergence circuit |
one presynaptic nerve fiberbranches and synapses with several postsynaptic cells; broad distribution of asignal as when sensory neurons bring information to different parts of thebrain |
|
convergence circuit |
many presynaptic nerve fibers combine to formone postsynaptic neuron; allows for conscious and unconscious control of breathing |
|
serial processing |
one neuron to another neuron, as from one partof brain to another |
|
parallel processing |
a single input neuron splits to stimulateseveral chains of neurons, each with a different number of synapses; allowsmany responses as same time as when you step on a tack leads to withdraw of onefoot, extension of the other foot, the feeling of pain and the screaming thatfollows |
|
reverberating circuit |
several single neurons stimulateeach other in sequence,A à B àC àD, except neuron C actually restimulates neuron A causing a repetitious signal that echoes or“reverberates” like a positive feedback loop -this occurs during a single inhalation of the lungs |
|
Reflex |
quick, involuntary, stereotyped reactions of glands ormuscles to stimulationProperties of reflexes 1. requirestimulation 2. quick, have few interneurons or synaptic delays 3. involuntary 4. stereotyped |
|
somatic reflexes |
involve the somatic nervous system |
|
reflex arc |
neural pathway of a reflex signal 1. somatic receptorsin skin, muscle, or tendon2. afferent nervefibers carry information to the dorsal horn of spinal cord or brainstem 3. integrating center synaptic contact in the gray matter
4. efferent nerve fibers carry motor impulses to 5. somatic effectors, the skeletal muscles |
|
monosynaptic reflex arc |
the afferent fibers synapse directly with thealpha motor neurons that return to the muscle, allowing only one synapse, thusmaking the reflex extremely quick |
|
stretch (myotatic) reflex |
a response to a stretched muscle in which the musclecontracts - important in stabilizing joints by balancing the tensionof extensors and flexors |
|
patellar reflex |
doctor taps patellar ligament with reflexhammer, stretches quad and results in extension of the leg |
|
muscle spindles |
stretch receptors embedded in the skeletal muscles, involvedin somatic reflexes, make up part of the body’s proprioceptors - muscle spindles inform the brain of muscle length and bodymovements - very abundant in muscles that require fine control andconcentrated near the tendons |
|
extrafusal fibers
|
muscle fibers outside the spindle, the “worker”muscle fibers |
|
intrafusal fibers |
modified muscle fibers within aspindle that can only contract at its ends |
|
alpha motor neurons |
innervate the working part of the muscle,extrafusal fibers |
|
gamma motor neurons |
innervate and stimulate the contraction of theends of intrafusal fibers adjusting the sensitivity of the muscle spindle |
|
polysynaptic reflex arc |
a pathway in which signals travel over many synapses ontheir way back to a muscle, a parallel after-discharge circuit, to create asustained contraction 1. tendon reflex 2. Withdrawal reflex |
|
1. tendonreflex |
reflex of contracting a muscle when the tendonis stretched |
|
golgi tendon reflex |
a response to excessive tension ona tendon, prevents alpha neurons from contracting so strongly |
|
golgi tendon organs |
proprioceptors located in a tendon near itsjunction with a muscle |
|
Withdrawal reflex |
pulling away from a painful stimulus |
|
flexor reflex |
quick contraction of flexor musclesto withdrawal a limb from possible injury |
|
Reciprocal inhibition |
as a muscle contracts in a reflex, theantagonist muscle is inhibited from movement to prevent the muscles fromworking against each other |
|
crossedextensor reflex |
contraction of extensor muscles in the limb opposite the onebeing withdrawn to keep your balance |
|
ALS (amyotrophic lateral sclerosis) |
“Lou Gehrig’s Disease”, progressive destruction of anteriorhorn and pyramidal tracts, resulting in the loss of speech, swallowing andbreathing |
|
Poliomyelitis |
destruction of anterior horn motor neurons bypolio virus |
|
Neuralgia |
nerve pain, caused by pressure from herniateddiscs |
|
Paresthesia |
sensations of prickling, burning, numbness, or tingling dueto nerve trauma or disorders |
|
Erb’s Palsy |
obstetric condition characterized by paralysisor weakness of a newborn’s upper arm muscles caused by a stretch injury to thebrachial plexus |
|
Paraplegia |
paralysis of lower limbs |
|
Quadriplegia |
– paralysis of sensory and motor control ofupper and lower limbs |
|
done |
done |