neuro exam 1 - glial cells

glial cells

supporting cells in the nervous system that work w=to allow neurons to operate which in turn maintains the nervous system

the neuron

works very hard to maintain its concentration and electrical gradients and that the action potential occurs correctly; burns ATP for the sodium potassium pump and it is overall very busy

glial cells

supporting cells in the nervous system that work w=to allow neurons to operate which in turn maintains the nervous system

the neuron

works very hard to maintain its concentration and electrical gradients and that the action potential occurs correctly; burns ATP for the sodium potassium pump and it is overall very busy

ATP

what does the neuron burn for the sodium potassium pump

glia

derived from the greek word for "glue" and is a non-excitable support cell in the nervous system

size of flia

generally smaller than nerve cells

number of glia

~1-5 x 10^11 cells and beats neurons in a ratio of 5:1; they comprise roughly half the volume of the brain

4 main types of glia

astrocytes, oligodendrocytes, ependyma, and microglia

astrocytes

form framework to support neurons and allow neurons to migrate during development as well as keeping them physically separate from one another

migrate

neurons are able to do what during development that helps promote synaptic connections with the help of astrocytes

separate

why do we want to keep neurons like this? because they must be organized into pathways with the help of astrocytes

k+

astrocytes also take up excess what

glucose

astrocytes store what to distribute to neurons as needed

capillaries

astrocytes connect neurons to these to channel oxygen and glucose; you need these to distribute things to other neurons

fill in spaces

astrocytes are very important in maintaining the shape and space inside our body so whenever there are dead neurons, the astrocytes do this

blood brain barrier

the biggest task of all for the astrocytes is the fact that they help form this key part of the brain

neuronal synapses

astrocytes can envelop these to restrict the movement of NT released by the pre-synaptic neurons as well as help remove NT that do not reach the post-synaptic cell from the synaptic cleft

oligodendrocytes

develop myelin sheath around neurons in the CNS; responsible for high conduction velocity of messages in the CNS; each of these myelinated multiple neuronal axons

ependymal cells

line the cavities of the brain and spinal cord as well as help circulate CSF and secrete/absorb nutrients to/from CSF; lastly, they help direct neuronal migration during development

microglia

these are the smallest glial cells that clean the junk out of our brain; they are usually dormant and provide immune response to pathogens invasion into CNS tissue; PHAGOCYTIC

phagocytic

engulf and remove dead cells or debris from dead cells

acoustic neuroma

benign tumor on the 8th cranial nerve; name indicates it is growth of neurons on the auditory portion of the nerve (more of a vestibular schwannoma); effect is compression of the nerve and disruption of coordinated action potential transmission

vestibular schwannoma

growth of Schwann cells on the vestibular portion of the nerve

8th

acoustic neuroma is a benign tumor on which cranial nerve

compression

what happens to the nerve that disrupts action potential transmission in patents with acoustic neuroma

internal auditory canal

if the tumor is located here, the axons are pushed against the hard walls of the auditory system and it has severe impact

cerebello-pontine angle

if the tumor is located here, there is enough space that you can have a large tumor and there will only be minimal damage or changes

vestibular schwannoma

presents with unilateral or asymmetric hearing loss; often accompanied by poor WDS, vertigo, tinnitus, and fullness; requires ABR and/or MRI for diagnosis

unilateral hearing loss

one ear works and the other doesn't work at all

asymmetric hearing loss

one ear works better than the other but both ears still have some function

tinnitus

a ringing in the ear

fullness

feels like there is gauze in your ear

audiogram for VS patients

threshold shift revealing that the left ear and only the left ear has neuronal hearing loss; only happening on one side meaning it HAS to be the auditory nerve; need to know how long this has happened for

short time

if this is the amount of time a patient comes in complaining they can't hear out of their left ear, it probably is not a tumor

months

if this is the amount of time a patient comes in complaining they can't hear out of their left ear, it is most likely vestibular schwannoma

afferent

info moving into a system; usually refers to info going into the CNS from the periphery

efferent

info going from the CNS; usually refers to info going form the CNS into the periphery

physical stimulus

sensory begins with the reception and transduction of a what (this can be light, sound, physical force)

sensory system

this system has the message propagated from the sensory cells to the brain which is afferent communication

afferent

for sensory system, this is the type of communication used

command generated

motor begins with what in the CNS (this could be moving your right index finger)

motor system

the message in this system is propagated from the brain to the muscle cells that execute the command as a form of efferent communication

efferent

for motor system, this is the type of communication that is used

receptors cells

transduce stimulus from the environment into neural signal (energy to electrochemical signal) which is the first step in the sensory afferent pathways

receive and deliver

most neurons do what with messages from one neuron to another neuron

receptor cells

if you don't have these, there will be no reaction the stimulus

receptor cells

located in the skin, retinas, cochleae, nose, tongue and in blood vessels also throughout the body

baroreceptors

detect changes in blood pressure

monitoring

the body is constantly doing what with itself to make sure things are working properly

retinal cells

these are the photoreceptors of the eye where they act as receptors that respond electro-chemically to light

pupil

light travels through this part of the eye

lens

light is focused by this part of the eye onto the retina

inner ear receptor cells

hair cells in the cochlea that respond to mechanical movement in the cochlea (electrochemically)

vestibular organ

hair cells are found in this area in the auditory system that can transduce movement in circular and linear direction

skin receptors

these can transduce pain, temperature, touch, and pressure stimuli

gustatory cells

taste receptors cells that have individual receptors that molecules connect to and respond to chemical properties of substances which are perceived as flavors

olfactory cells

molecules evaporate off from matter and are inhaled into noise and strike these receptor cells

effectors

use/deliver neural signal to create an action; refers to muscles/glands that execute the neural signal and terminal of peripheral efferent pathways

skeletal muscle

segmented muscle tissue designed for fast movements (short duration); combination of afferent sensory info and efferent motor units that combine to give feedback to CNS

muscle contraction

muscle beings at origins and ends at insertion which is this concept

origin

muscle attachment to the stationary bone where it begins

insertion

The attachment of a muscle tendon to a moveable bone or the end opposite the origin and where the muscle ends

origin

contraction of the muscles brings the insertion closer to the what

2 proteins in muscle

myosin and actin

myosin

forms thick muscle fibers; makes the connections to the other protein's fibers

actin

forms thin muscle fibers

myosin pulls back actin

energy is expended as what happens to contract muscle towards the origin point

size and strength

the amount of myosin and actin dictates what two things of muscle contraction

smooth muscle

used for slower and simpler movements over larger segments of the body; controlled largely by parasympathetic fibers; one neuron controls many muscle fibers

parasympathetic fibers

for smooth muscle, what is it controlled mainly by (what kind of fibers)

motor unit

comprised of motor neurons, peripheral axons, and motor-end plates; these arise from the spinal cord to connect CNS to PNS

spinal cord

motor neurons arise form this to connect the CNS to the PNS

motor end-plate

this is also called the neuromuscular junction

neuromuscular junction

point at which the motor neuron innervates muscle cell and makes synaptic contact with the muscle cell; an EPSP evokes contraction and executes action made by motor system

neuromuscular spindle

provides afferent info from muscle about muscle length and changes in length (which is very important in articulation disorders)

afferent info

tells you what's wrong and allows you to know that the movement was wrong

reflexes

drive largely by ganglia in the spinal cord; controls tonic muscle tone and responses to sudden environmental changes

ganglia in spinal cord

reflexes are driven largely by these which are clusters of sensory and motor cell bodies as well as reducing transmission time to/from the CNS

tonic muscle tone

reflexes control this and response to sudden environmental changes

Charcot-Marie-Tooth syndrome

hereditary peripheral neuropathy; CMT1 = demyelinating, CMT2 = axonal dysfunction symptoms being in the feet or legs

CMT1

demyelinating where the neurons are there but they don't have any myelin functioning properly

genetics

Charcot-marie-tooth syndrome is highly dictated by this

CMT2

axonal dysfunction

drop foot syndrome

peroneal nerve controls muscle contraction and tone of the muscles in the front of the ankle and top of the foot; neuropathy causes toes to point down

peroneal nerve

what nerve controls muscle contraction and tone of the muscles in the front of the ankle and top of the foot

neuropathy

this is what causes the toes to point down

drop foot patient action

patients of this must lift feet higher off the ground when walking to avoid their toes hitting the ground... error of reflex

cranial nerves

CMT is relevant because it can spread to other regions of the body including these which can affect speech, swallowing, posture, and hearing

cranial nerves

affects speech, swallowing, posture, and hearing

pediatric CMT

this disorder does NOT significantly affect thresholds and average hearing level

speech perception in CMT

the only thing that showed the patients having signs of difficulty was responding to words while competing with background noise

background noise

audiograms won't necessarily capture this disorder as a deficit because you must challenge the auditory system by exposing the patient to this. this is the best indicator that there is actually something wrong