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neuro exam 1- hoodin
micro-anatomy
Question | Answer |
---|---|
the opposite of anterior is | posterior |
cephalic is toward the brain, toward the tail is | caudal |
mideal means toward the middle, what means toward the side | lateral |
a frontal section of the brain is divided | front to back |
a sagital section divides the brain | left to right |
a telephone system that allows the brain to communicate with all parts of the body | the nervous system |
the part of the nervous system that has motor information | central nervous system |
the information going out/efferent information | motor information |
the information from the environment that comes into the body | sensory information into the periperal nervous system |
cns is composed of these 4 parts | cerebrum, cerebellum, brain stem, spinal cord |
the function of the cerebrum in the cns | pair hemispheres- takes care of higher cognitive function- planning, language, problem solving |
the function of the cerebellum in the cns | back of the brain- one of the 3 motor control centers |
the function of the brain stem in the cns | 1) transmissive function- caried info in and out of cns, pns 2) mediates complex reflexes- vegatative (breathing, swallowing, etc)...also bridges the cerebrum and cerebellum |
the function of the spinal cord in the cns | carries sensory (ascending) info up and motor (descending) info down- not much circuitry-involves simple reflexes |
peripheral nervous system | spinal and cranial nerves |
spinal nerves in the PNS | mixed nerves- 31 paired- exit the lateral edges of the spinal cord- sensory and motor branch- provide innervation (communication) with the area below the neck |
cranial nerves in the PNS | provide innervation in the neck and head- 12 paired nerves- sensory and motor branch- |
autonomic nervous system (ANS) | made up of the branching of spinal and cranial nerves- mostly in the PNS- role: provided automatic functions-internal states we dont think about |
sympathetic branch - autonomic nervous system | fight or flight- in states of arousal- pumps blood to major muscles |
para-sympathetic branch- autonomic nervous system | in states of relaxation- pumps blood away from muscles and to the stomach for digestion |
another way to indicate away from the body or close to the body is | distal and proximal |
cross section of the spinal cord is called a | transverse section |
homeostasis | maintains and keeps the body stable |
glial cells | supports cells- if you have a brain tumor- it grows in these type of cells |
glial cells in the cns | astrocytes- microglia - oligodendroliglia - ependymal cells (charoid plexus) |
role of astrocyte glial cell - cns | 1)supportive (phagocytosis) 2)provides a blood/brain barrier 3) isolates the synapse-providing a barrier where the neurons communicate |
role of the microglia glial cell- cns | housekeeping - phagocytosis |
role of the oligodendroglia glial cell-cns | provides an myelin sheath around the axon of the neuron in the cns- isolates and insulates - sheath is white/lipid/fatty 30x1 ration nueron cell to sheath cell |
role of the ependymal cells (chariod plexus) glial cells in the cns | manufacture cerebral spinal fluid - lines the ventricles of the opening (cavities of the brain) |
glia cells in the pns | satelitte cells- schwann cells - fibroblasts |
role of satellite glial cells - pns | provides physical support to the neurons |
role of schwann glial cells - pns | provides myeling sheath to the neurons in the pns- there is a 1x1 ratio of myelin cells to neuron cells |
role of fibroblast glial cells - pns | sheath that surrounds the nerves- holds the bundle together and provided unity of purpose |
neuron | nerve cells in the cns and pns- basic functioning part of our nervous system- appx 50 billion in our body- only cell that has the "property of excitability" if stimulated sufficiently, it can shoot an electric charge down its length |
soma | cell body |
dentrites | extrusions from the cell body which carry electic charges to the cell body |
axon | carries electric charges away from the cell body |
cell membrane | seperates the extra-cellular fluid for the intra-cellular fluid |
arborization of the axon | branching out of the axon |
termial button | the swollen area on the axon - pre-synaptic membrane |
receptor site | the swollen area on the dentrite - post-synaptic membrane |
synaptic gap | the gap between the receptor site and the terminal button |
neurotransmitter | general term for chemical- located in a vesicle inside the terminal button- when the term button gets excited- the vesicle secretes the chemical into the synaptic gap & attaches itself to the receptor site and has an effect on it |
effect the neurotransmitter has on receptor site | when the chemical attaches to the receptor site- it creates an electrical charge and changes the charge and changes its permeability |
change of permeability | substances that once could not pass thru now may be able to |
physical chemistry of a synapse (pt 1) | *creates and electrical charge *changes the permeability * if the receptor site is for a specific chemical, it like a key to that site |
physical chemistry of synapse (pt 2) | some chemicals wont open the door (wrong key)- neurotransmitters like receptor sites, so it goes there - chemicals influence the receptor site |
examples of neurotransmitters | seratonin, dopamine |
3 forces that influence a synapse | 1) sodium (+) out potassium (+)in pump 2) potassium(+) leak out 3) protien amin (-) |
resting potential | equilibrium of a neuron- (-)70Mv- when there is balance on the inside and outside of a neuron- at rest there is more sodium outside and potassium inside |
action potential | occurs when a neuron sends info down its axon away from the cell body (-)50Mv |
ipsp- hyperpolarization | inhibitory post-synaptic potential- decreases the chance neuron will fire due to flow of negative into the cell and positive out |
epsp- hypopolarization- | excitatory post synaptic potential- increases the change the neuron will fire due to the flow of positive into the cell |
graded potential | over time and over space, the magnitude of the charge decrease-farther has a smaller influence than ones that are close |
axon hillock | the area on the neuron where the cell body connects to the axon- its the location where the threshold of firing can or wont occur due to influence of EPSP or IPSE |
absolute refractory period | after firing- neuron must have this time to rest |
relative refractory period | only a super force could excite the neuron to fire |
threshold of firing | -50 Mv when sufficient stimulation is recieved at the axon hillocks-it sends a wave of permeable change down its length- fires or doesnt- on or off |
all or none law | threshold and magnitude are fixed- if a neuron reaches threshold, it always fires, and always with the same magnitude |
summation | if two synapses occur close to another you get a bonus point |
temporal summation | synapses close in time |
spatial summation | synapses close in proximity |
axodendritic synapse | axon sends dendrite receives |
axosomatic synapse | axon sends soma receives |
axo-axonal syanpse | axon send axon receives (receiever is prevented from firing due to IPSP |
myoneural junction | in cranial and spinal nerves- motor neurons that go to the muscle fibers when synapse happens- muscle fibers contract because of synapse neuron and muscle fiber |
nodes of ranvier | breaks in the myelin sheath - charge moves down the axon skipping from node to node |
saltatory conduction | charge moves faster in myelinated neurons |
axons with bigger diameter and more myelin travel | fastest |
non-myelinated neurons and small diameters travel | slower |
motor system activities required skilled movement are characterized by descending neurons of | great diameter and heavy myelination |
when synapse occurs- the chemical influence is only available to the receptor site for a short time due to | deactivation and re-uptake |
deactivation | the receptor site secretes an enzyme which goes out an kills the neurotransmitter (ex. chemical acylocholine is killed by enzyme acylcholinstrasse) |
re-uptake | the terminal button draws the chemical back into it |
neuro-leptic medication impede-enzyme | medication that is given that impedes the neurotransmitter |
neuro-leptic medication inhibit-enzyme | medication that is given that goesafter theneurotransmitter and inhibits it- ex. ssri selective serotonin reuptake inhibitor- paxil, zoloft, prozak) |
mimic transmitter- medication | manufacture the "key" that opens the door- ex. methadone for heroine |
provide chemical precurser medication | ex brain cannot produce dopamine- so a chemical (pill) levadope is given and it enables the brain to produce dopamine - dopamine cannot cross blood barrier- chemical levadope can |
spinal nerves of the PNS | 31 pairs of spinal nerves- grey matter- nerves exit along the lateral edges of of the spinal cord- dorsal spinal cord- sensory root comes out; ventral spinal cord- motor root comes out of |
dorsal root ganglion | massive nerve cell bodies in the PNS- sensory part- uni-polar neurons |
spinal nerve cycle | receptor (stimulation from environment)send a msg up the spinal sensory nerve-to sensory root ganglion- goes via dendrite in spinal grey and synapses on the axon of the motor root- send info to the muscle |
cranial nerves in the CNS | 12 pair |
motor unit | the motor neuron PLUS the muscle fibers that it innervates |
lower motor neuron | its the most peripheral - as low as it gets- connects the spinal cord and brain stem to muscle fibers- brings the nerve impulses from the upper motor neuron out to the muscles- lower motor neurons axon terminates on the muscle |
final common pathway | refers to the lower motor neurons- its the only route to the muscle fibers- it its severed, loses contact with the brain |
denirvation | if the connected between the muscle fibers and lower motor neuron gets damages or severed-and they no longer receive energy |
atrophy | loss of muscle mass due to death of the muscle/connection |
speech musculature ratio (muscle fiber/neuron) | 200 x 1 - its and intermediate range with respect to skilled movement- (eye ball movement-1x1...back movement 200 x1-not much skilled) |
types of muscles | smooth, stiated, cardiac |
cardiac muscle | muscle of the heart- keeps it pumping |
smooth muscles | not a voluntary muscle- lines the brain- carries food down the esophagus |
striated muscle | most important in speech- voluntary control- skilled movement |
speech musculature | oropharyngealaryngeal (peri-oral) overlaps with respect to fuction- use the same muscles in speaking, swallowing, chewing, coughing, etc |
reflex | stereotyped motor response directly tied to a stimulus- need not involve higher senses- could just be a simple reflex (spinal) or could be complex (brain) |
3 types of reflexes | 1)mono-synaptic extensor reflex 2) principle of reciprocation innervations 3) muscle tone reflex |
basal ganglia | movements and reflexes are organized here- facilitates needed portions of movement and inhibits unwanted movement |
ex of damage to the basal ganglia | parkinson's disease- unwanted movement present |
mono-synaptic extensor reflex | simplest conceivable reflex- done at spinal level |
mono-synaptic extensor reflex circuit | get environmental stimulation - go to sensory cell body- synapse with lower motor neuron- a limb moves |
principle of reciprocation innervations | involves contracting of one and relaxing of another muscle- antagonist is the prime mover- agonist (opposite) relaxed |
principle of reciprocation innervations- circuit | environmental stimulation- sensory cell body syapses with motor at the same time internuncial neuron are are communicating between cns and pns |
internuncial neurons | function neurons-connecting neuron- usually a pathway between 2 neurons- motor and sensory- the more movement-more internuncial neurons involved-they can go across or up/down/side -cerebellum (motor control center)is made up mostly of internuncial neurons |
preferred pathways | like muscle memory- developed movements that youve done a lot- internuncials remember these movements- ex. athletes able to move a specific way |
muscle tone | its residual tightness gives muscles shape- as long as your alive and neurologically ok, you will always have muscle tone- you can voluntarily change-you set your muscle tone based on the job at hand |
muscle tone reflex | the most complex level of reflex- skilled movement gets superimposed on muscle tone |
circuitry for muscle tone reflex pt 1 | body says "more muscle needed"*msg from cortex descends down to the upper motor neuron*synapses with gamma motor neuron*fires*synapses with intrafusal muscle fibers*increases tension/decreases diameter*stimulates annulospiral sensory neuron*fires* |
circuitry for muscle tone reflex pt 2 | synapses with alpha motor neuron*fires*syapses with extrafusal muscle fiber*extrafuasal contracts*diameter of intrafusal is reduced and the circuitry stops |
muscle-flex (paletal reflex) | when doc hits knee he hits the extrafusal fiber causing it to stretch and start the circuitry |
extrafusal muscle fiber | skeletal muscles outside the bag muscles |
intrafusal muscle fibers | fibers in the bag |
somatosensory system | all of the feelings/sensations from our body-touch, pain, tickle,itch, everything has sensory receptors- every sense had a receptor-receptors take the environmental influence and transform into an electric charge |
pain and touch receptor | free nerve endings- among the cells of your skin-dendritic fibers are amongst your skin cells |
fine touch receptor | you use these receptors to identify objects by touching them-nerve ending encapsulated |
diffuse receptors | you use these receptors if your blind or in the dark to feel you way around...expanded nerve endings |
proprioception (body awareness) receptors | most complex- uses 3 sources collectively working together- a) muscle spindles:stretch b)tendons-golgi tendon organs sensitive to :tension c)joints-sensitive to :pressure |
alpha motor neuron | innervates with the extrafusal muscle fiber of the skeletal muscle- responsible for contraction |
gamma motor neuron | innervates with intrafusal muscle fibers (in the bag) |
annulospiral sensory neuron | gets innervated from the intrafusal muscle fiber |