MBB 1 Flashcards
mnemonic for short acting local anesthetics
Poor Ester, she was deCLARED too SHORT to be an ARTIST
Procaine (converted to paba)
Chloroprocaine (v short duration)
articaine (v rapid onset)
why do some people experience phantom limb pain?
because the brain has redistributed the cortical region that used to belong to the amputated limb to other parts of the body
the mind still perceives that the limb is present, so stimulation of the body part that has cortex from the phantom limb will also cause sensation on area where limb used to be
What part of the body has no nociceptors?
BRAIN
what are the 3 types of nociceptors; which is most common?
- polymodal mechanoheat receptors (respond to extreme pressure and temp and allergens) –> MOST COMMON
- mechanonociceptors (alpha delta fibers, pin prick pain)
- silent nociceptors (inflammation)
what protein is necessary for differentiation of ventral spinal cord
sonic hedgehog (SHH)
how does deep brain stimulation work?
- tries to prevent haphazard firing of subthalamus
- stimulation tries to decrease stimulation of subthalamus or globus pallidus internal to weaken indirect pathway (allows for some compensatory movement)
what separates the temporal lobe from the frontal and parietal lobes
lateral fissure (sylvian fissure)
emotional processing requires both _______ input and ______ processing
peripheral
central
what will happen to the generator potential if you stimulate a nerve ending at two places?
what term describes this
- IT WILL INCREASE
spatial summation
what happens if you lose olfactory neurons?
you can make more via basal cells! (decreases as you get older)
in weber’s syndrome, what is affected
- occulomotor nucleus, corticospinal and corticobulbar tract –> contralateral body paralysis, contralateral lower facial paralysis, contralateral tongue, ipsilateral oculomotor paralysis (dilated pupil, down and out, droopy eyelid)
name three conditions associated with inhibitory interneuron dysfunction in the cortex
- epilepsy, overexcitation of inhibitory interneurons
- hyperacusis, auditory system has lost control of excitation and inhibition,, any soudn is associated with painful stimuli
- schizophrenia- malformation of inhibitory interneurons
if you lose your vertical gaze center what happen
if you lose your paramedian pontine reticular formation what happens
if you lose your frontal eye frields what happens?
if you lose your superior colliculus, what happens
if you lose a portion of place code, what happens
- can’t do verticle saccades
- can’t do horizontal saccades
- can do saccades, but will take longer and will be off
- can do saccades, but will take longer and will be off
there is redundancy between left frontal eye fields and supercolliclus
you will have a blindspot/blind sight that corresponds to that location in space (can still do imagined targets, but not fixed targets )
what role does the pag and it’s downward structures play in sensation?
- can provide analgesia via stimulation (opioids at any of these levels can do this)
- stimulates raphe nuclei (which is serotonergic) which goes down and stimulates dorsal horn to relieve pain
what separates the alar and basal plates
sulcus limitans
name the three components of a local anesthetic and what they are important for
lipophilic- potency, duration of action
ester/amide- metabolism, hypersensitivity
hydrophilic- mechanism of action, onset of action
what is wallenberg’s/lateral medullary syndrome?
can be due to occlusion of pica as it goes around medulla
will affect spinocerebellar tract –> ataxia
spinal trigeminal ganglion –> ipsilateral facial pain and temp loss
lateral spinothalamic tract –> contralateral body loss of pain and temp
what are the five biogenic amines
- dopamine, norepinephrine, epinephrine, serotonin, histamine
for the parasympathetic nervous system:
what are the length of pre and post ganglionic neurons
what does each ganglion release
where do the nerves for this system originate
what does this system regulate
What parts of the body have no parasympathetic innvervation
- pre are long and post are short
- pre and post release acetylcholine
- brain stem (cranial nerve 3,7,9,10) and sacral spine (S2-4)
- rest and digest (slows heart, mucus glands, digestion, urination)
- arms, leg, blood vessels of head and neck, adrenals
after a stroke, some patients get severe spontaneous pain to certain areas of the body
describe why and what the term for this is
what can you do to treat it
- damage to somatosensory tracts that deliver pain –> leads to cortico pain neurons going wild
- thalamic pain or central pain syndrome
- mirror visual feedback for repetitive transcranial magnetic stimulation
describe the anterolateral pathway of bring general visceral afferents back to the spine/brainstem
- general visceral afferents go via splanchnic or spinal nerve back through dorsal root ganglion, decussate, and then go up dorsal column to nucleus solitarius OR synapse on interneurons/motor neurons for reflex
what local anesthetic should you use if yo u are intolerant to epinephrine? why?
mepivacaine, has the least vasodilating effect
what parts of the ear are affected in sensorineural hearing loss?
inner ear and beyond!
what condition is optic neuritis classically associated with?
multiple sclerosis
failure of the anterior neural pore to close causes what?
failure of the posterior neural pore to close causes what?
what can prevent majority of neural tube defects during pregnancy
anencephaly
spina bifida
folic acid
what parts of the brain does the posterior cerebral artery innervate
inferior temporal lobe and occipital lobe
describe the pathway for micturation and include the three types of nerves present
sympathetic (L1-3), sensory from hypogastric, keeps bladder relaxed and internal sphincter closed
parasympathetic (S2-4), sensory from pelvic nerves, contracts bladder and relaxes internal spincter
somatic (S2-4) sensory and motor from pudendal nerve, tonically contracts external sphincter until instruction from pons
- bladder distension is senses and goes up to pons which coordinates parasympathetic activation, sympathetic inhibition, and inhbition of the pudendal nerve/external sphinctor
what are the two types of neurons involved in the corticospinal and corticobulbar tracts
layer V pyramidal neurons
betz cells
for what kind of stroke is tpA indicated
in what window can you administer tpa
ischemic stroke (contraindicated for hemorrhagic stroke)
less than 3 hours from onset of symptoms
what are the three chambers of the cochlea? what fluid are they filled with?
MTV used to be famous on a grand SCALE
scala media (endolymph) scala tympani (perilymph) scala vestibule (perilymph)
What is the medial geniculate nucleus involved in?
what is its input from
where is its output
what does a lesion here cause?
- audition
- inferior colliculus
- primary auditory complex
- no deficit since projections are bilateral, deficits only if lesion is bilateral
what is the difference between pyramidal smile and extrapyramidal/duchenne smiling?
where do they converge?
pyramidal- voluntary smiling (motor cortex)
extapyramidal/duchenne- involuntary smiling (hypothalamus)
reticular formation
the strength of long term potentiation or depression is dependent on the time between presynapse activity and post synapse activity; what is this phenomenon called?
if the presynaptic activity precedes the post synaptic activity, what will this result in?
if the post synaptic activity precedes the pre synaptic activity, what will this result in?
- spike-timing dependent plasticity
- long term potentiation
- long term depression
what is a transient ischemic attack (TIA)
what is it strongly associated with
what are clinical manifestations?
- a <5 min episode of ischemia that resolves itself
- atherosclerosis (aka high indicator that another attack or stroke will occur)
- left arm numbness, monoocular blindness, facial numbness, language disturbance, dizziness
what is syringomyelia?
what deficits would you expect
- condition of ballooning of the central canal in the spinal cord (usually due to chiari malformation)
- destruction of ventral white commissure –> bilateral loss of pain and temp
the ____ (more,less) myelinated and the ______ (larger/smaller) the diameter of a neuron, the higher the susceptibility of a local anesthetic to cause a block
give an example of a neuron like this
less myelinated
smaller diameter
pain neuron
the _______ is the weakest amount of stimulus necessary that can be detected 50% of the time
absolute threshold
describe activity dependent/experience dependent learning in the context of long term potentiation and long term depression
- increased use of certain synapses and decreased use of synapses allows the brain to adapt over time
long term potentiation- synaptic strength increases when presynaptic and post synaptic neuron fire simultaneously (neurons that fire together wire together)
long term depression- synaptic strength decreases when presynaptic and post synaptic neurons fire asynchronously (neurons that fire out of sync lose their link)
what is encoding failure
what is retrieval failure
- when your ability to consolidate is disrupted, aka by substance abuse or trauma
- the memory is stored but you can’t retrieve it
how much of glucose is used for aerobic respiration, glycogen synthesis, amino acid synthesis, and nadph synthesis
85% aerobic respiration
5% amino acid synthesis
5% glycogen synthesis
5% nadph synthesis
describe energy consumption from the prenatal period until adulthood
- prenatal more anaerobic (glycolysis) than aerobic (little oxygen used)
- birth to 6 months- less dependence on glucose and more dependence on ketones from fatty breast milk
- after 6 months and throughout childhood, will use aerobic respiration af (50% of body consumption of o2 between 4-9)
- o2 consumption decreases to 20% in adulthood
which semi circular canal resides on which axis and give an example of a motion that would activate the canal
- horizontal canal –> z axis, saying no
- anteriorcanal —> y axis, saying yes
- posterior canal –> x axis, cartwheel
name the 4 things that neural crest cells differentiate into?
MANS melanocytes autonomic ganglia neurosecretory cells sensory ganglia
what are the three types of ionotropic glutamate receptors; what functions are they involved with?
does glutamate bind to metabotropic receptors?
which receptor may require a co-agonist? name the co-agonist
AMPA: everywhere, used in most excitatory synapses
NMDA: used in learning, memory, synaptic plasticity
Kainate: not well understood
yes!! 3 classes (don’t need to know specifics)
NMDA receptor- glycine
where on the spinal cord do upper motor neuron axons from the motor cortex go? what does this mean about what lower motor neurons they regulate?
where on the spinal cord do upper motor neuron axons from the brain stem go? what does this mean about what lower motor neurons they regulate?
- lateral white matter, regulate lower motor neurons that affect distal structures/fine touch
- medial white matter, regulate posture and balance
what artery supplies the putamen, caudate and internal capsule?
what does it branch off of
lenticulostriate artery
middle cerebral artery
depression has been associated with increased blood flow to which region of the brain?
what can decrease the blood flow?
pre frontal cortex
anti-depressants, ssri
what is the difference between a noncommunicating hydrocephalus and a communicating hydrocephalus?
non-communicating- due to obstruction of csf flow, so csf accumulates through anterior fontanelle
communicating- issue with reabsorption from arachnoid granulations
what is tabes dorsalis
what deficits would you have
- demyelination of afferent fibers bilaterally in dorsal column
- will have bilateral loss of fine touch/proprioception
where in the thalamus do body somatosensory neurons synapse?
what about head somatosensory neurons?
what brodmann’s areas do they project do?
VPL
VPM
Brodmann’s 3,1,2
what is the medial longitudinal fasciculus?
what is it involved in
the tract of nerves from the abducens nucleus to the occulomotor nucleus
- voluntary gaze/ medial rectus contraction
what is a specific receptor that modulates synaptic plasticity of thalamic cortical nuclei?
does this process happen all the time?
- nmda receptor (glutamate)
- only during critical period
what would happen to your memory if you lose your hippocampus? what types of memory are unaffected
- can’t consolidate declarative long term memory
- working memory and long term nondeclarative memory
the cavernous sinus and superior sagittal sinus drain into the ______
transverse sinus
what are two ways to convey the intensity of a stimulus
- increase the number or frequency of action potentials (NOT THE SIZE THOUGH)
- increase the number of sensory receptors involved/recruited (ex: a small stimulus only stimulates one receptor but a strong stimulus stimulates/recruits multiple sensory receptors)
what is bitemporal hemianopsia?
what can cause it? what is a sudden severe version of this called?
- loss of temporal visual field bilaterally
- anything that compresses optic chiasm, usually pituitary tumor
- if sudden growth of tumor or hemorraging of tumor –> pituitary apoplexy
What is the pulvinar involved in?
what is its input from
where is its output
what does a lesion here cause?
- higher order visual processing
- super and inferior colliculi, lateral and medial geniculate nuclei
- attentiona/neglect deficit syndromes
the lower the pK, the _____ (slower,faster) the onset of a drug. why?
faster
more of molecules is in unionized/uncharged form, so it can diffuse faster
what size motor unit is better for fine touch/detail?
what size motor unit is better if you need to generate significant force?
what motor unit has the lowest threshold for innervation? what about highest threshold?
- small
- large
- small
- large
what role does the nose play in taste?
- large role, odorants from food go up behind palate and into nose, if you have cold or loss of olfaction, food doesn’t taste as good
If a patient had right abducen nerve palsy, what would happen if you asked the patient to look to the right? what would if you asked them to look to the left?
- if they looked to the right, the left eye would function normally and move to the right but the right eye would not move (esotropia)
- if they looked to the left, both eyes would function normally and look to the left
what cortex is in the post-central gyrus
somatosensory cortex
in medial pontine syndrome, what is affected
- abducens nucleus and corticospinal tract –> ipsilateral lateral rectus paralysis and contralateral body deficits
what is the limbic system composed off
what is its function?
- components of telecenphalon, diencephalon, and mesencephalon,
aka fornix, cingulate gyrus, amygdala, nucleus accumbands, hypothalamus, mammillary body, hippocampus
- MLEM Please motivation learning emotion memory pleasure
how do dry and wet age related macular degeneration differ?
which form can be halted or reversed, with what
dry: slow progressive bilateral loss of central vision (most common)
wet: complication of dry, oxidative damage to choroid vessels leads to increases vegf and neovascularization that hemorrhages (CAN BE REVERSED OR HALTED, WITH INTRAOCULAR ANTI VEGF))
what protein is necessary for differentiation of the dorsal spinal cord and hind brain
bone morphogenic protein (BMP)
what protein is necessary for differentiation of neural crest cells and cerebellar granule cells
Wnt
describe the stretch/deep tendon reflex
- monosynaptic
- feel extension stretch (ex: filling drink) –> 1a and II afferents activated and synapse on alpha motor neurons to flex the same muscle
- -> send excitatory synapse to synergistic muscle to help
- -> send inhibitory synapse to antagonist muscles
what is the place code in reference to vision?
for the vestibuloocular reflex, how do you convert place code into rate code?
- the fact that every point along an x y axis of your vision has a specific place in the brain that encodes it
- the faster your head moves, the faster and more frequency action potentials are sent to the placecode, which is hard wired to the eom
What is the ventral lateral region involved in?
what is its input from
where is its output
what does a lesion here cause?
- modulation of coordinated movement
- cerebellum
- primary motor cotex
- akinesia (loss of voluntary movement)
describe the nerve fibers in the pathway for the baroreceptor reflex
- blood pressure increases, which the carotid body sinus detects via stretch; glosopharyngeal afferents are sent and go through petrosal ganglion and synapse in nucleus solitarius, then motor afferents via vagus go through nucleus ambiguous and to heart to decrease hr and relexively sympathetic is inhibited
what condition is drusen associated with
age related macular degeneration
what area of the brain is associated with comprehension of language?
in what lobe is this area?
wernicke’s area
temporal lobe (think, its in the same lobe as hearing)
what are the two main functions of the pons
what are other functions
- regulation of breathing (pneumotaxic center) and signal transmission within the brain (ie to or from cerebellum or cerebrum)
- balance, hearing, taste, deep sleep
what lab value will be elevated during pregnancy if a neural tube defect is present?
what two sources can you measure this lab value from?
- alpha feto protein
- maternal serum or amniotic fluid
describe symptoms of lower motor neuron syndrome
paresis or paralysis hypotonia hyporeflexia atrophy fibrillations or fasciculation flaccidity
describe the pathway from the putamen being activated to the cerebral cortex (direct pathway)
1) need significant input from multiple inputs to surpass significant threshold in putamen spiny neurons
2) release GABA, which inhibits the globus pallidus internus
3) this disinhibits GABA release from the gp internus to the thalamus
4) now the thalamus can send signal to specific places in the cortex to activate specific motor neurons
what is the miller law of 7?
max you can remember is 7 units +/- 2
if you want visceral pain to reach consciousness in the brain, what pathway do you take?
describe the pathway
dorsal column pathway
-enter the dorsal horn and synapse at midline, then travel up the dorsal column (with medial lemniscus) and eventually reach VP of thalamus which then synapses on the cortex
which two sections of the spinal cord are enlarged and why?
- cervical (C3-T1) for increased nerve cells and connections to process information from the arms
- lumbosacral (L1-S2) for increased nerve cells and connections to process information from the legs
in additon to v and t snares fusing, what is a necessary protein that links vesicle release to ca influx?
synaptotagmin
what is the mid brain composed of?
what does it do?
- tectum (posterior)
- cerebral peduncles (tectum and crus cerebri)
- VHS TAMpering vision hearing sleep/wake temperature regulation arousal motor control
give examples of crude touch modalities
in general are the axons big and myelenated or small and unmyelenated
pain
coarse touch
temperature
- small and unmyelenated
what are optokinetic movements
how does this differ from vestibulo-ocular movements
- you are in an object that is moving and you are stabilize your gaze on an object passing by, and then your eye is capable of shifting and stabilizing on the next object (optokinetic nystagmus)
- this is movement of the eyes that will stabilize the gaze when your head is bobbing/moving (will move in the opposite direction of your head) (vestibulokinetic nystagus)
what is a main difference between bupivicaine and ropivicaine? (2 things)
bupivicaine is significantly more cardiotoxic and can be used post-joint replacement surgeries
what is the main difference between nonproliferative and proliferative diabetic retinopathy?
- proliferative has neovascularizations/angiogenesis
in medial medullary syndrome, what is affected
- hypoglossal nerve and cortico spinal tract –> contralateral body deficits and ipsilateral tongue deviation
parkinson’s disease is due to neurodegeneration of what?
what symptoms do you get a result and why
what medication can help treat and why
substantia nigra pars compacta
bradykinesia (slow movement), rigidity and stooped posture, resting tremor (hypokinetic tremor)
- due to the fact that now you need higher threshold for activation direct pathway and lower threshold for activating indirect pathway
L-dopa- dopamine precursor, will create more dopamine to make remaining dopamine pathways stronger
what is the difference between anterograde and retrograde amnesia
anterograde- can’t form new memories
retrograde- can’t retrieve old memories
what are the three types of GABA receptors
GABA A- everywhere ,implicated in many drugs (benzos, Alcohol, steroids, Anesthetics
GABA B- metaBotropic
GABA C- in the eye (C is for SEEing)
which anesthetic type is metabolized in the liver?
- amides
what neuron is responsible for regulating the synapse between ganglion neurons and bipolar cells
amacrine cell
describe the pathway of memory input in the hypothalamus
name a clinical scenario that often implicates this pathway
- from the hippocampus via the fornix to the mamillary body to the anterior hypothalamus
- Korsakoff’s from b1 deficiency and drinking –> short term memory loss due to damage to mamillary body
what is proprioception?
what are the size of the axons
- recognizes our self position and movement
- large and myelinated
what is the trace decay theory?
- there is a path to where a memory is stored, and if you don’t rehearse the memory, then the path to that memory wil fade but the memory will still be there
a stimulus causes a(n) _____ potential
if the stimulus is strong enough to reach threshold, it becomes a(n) _____ potential
- receptor/generator
- action
what functions does the medulla do?
- regulation of breathing
- heart and blood vessel function
- digestion
- sneezing
swallowing
what is the most common demographic to get vertigo?
old women
name four cns diseases can affect smell and taste
dementia
parkinsons
multiple sclerosis
schizophrenia
what kind of receptor are hair cell receptors?
mechanoreceptors
what local anesthetic can cause methemoglobinemia?
what can you use to treat it?
- prilocaine
methylene blue
what is the only glial cell in the retina?
what does it do
muller cell
- keeps parallel array of retinal layers and eats dead neurons
what are the two membranes of the cochlea
tectorium and basilar
if you have 3rd nerve palsy, what should the affected eye look like?
- dilated, pointing down and out (only 4th and 6th nerve muscles working, aka superior oblique and lateral rectus), droopy eyelid
What is the VPL and VPM involved in?
what is its input from
where is its output
what does a lesion here cause?
- somatosensation for head (VPM) and body (VPL)
- VPL–> medial lemniscus
- VPM –> ventraltrigeminothalamic tract
lateral spinothalamic tract (lateral funniculus) - somatosensory cortex
- contralateral loss of all somatosensation
in humans, the rostral caudal axis is tilted forward due to the _________ made during embryogenesis
cephalic flexure
what parts of the brain does the middle cerebral artery innervate
frontal lobe, parietal lobe, and temporal bone
where do layer 2 pyramidal neurons go to?
where does layer 3 pyramidal neurons go
where do layer 5 pyramidal neurons go
where do layer 6 neurons go
- go through cortex layers and to other cortices within same hemisphere
- go through cortices to cortices within the same and contralateral cortices
go to subcortical structures like superior colliculi, brainstem, spinal cord
- thalamus
what do hair cells have on their surface to detect vibration?
what connects them to each other?
stereocilia
tip links
what part of the hypothalamus is sexually dimorphic
preoptic area
what do interneurons do within the 6 layers of the cortex?
- inhibitory, turned on my pyramidal neurons, act locally usually within the same layer
What is the anterior nucleus involved in?
what is its input from
where is its output
what does a lesion here cause?
- memory, emotion
- mamillothalamic tract
- cingulate gyrus
- significant memory deficit/amnesia
80% of neurons in the cortex are _____ neurons
what are layer 4 neurons called
pyramidal/principal neurons
- stellate neurons
what is the main neurotransmitter for pain? what does it do
SUBSTANCE P (P FOR PAIN)
- sensitizes nociceptors
- potent vasodilator
- releases 5ht from platelets
- releases histamine from mast cells
what are the two type of muscle spindle receptors? how do they differ?
- Group Ia: rapid adapting, respond to changes in muscle stretch and vibration
- Group II: slow adapting; respond to sustained stretch/limb position
what are the two major sites of action for norepinehprine and what functions does it facilitate
what transports norepi into vesicles
what enzymes break it down
what type of post synaptic receptors does it bind to?
- periphery- sympathetic nervous system
- locus ceruleus- attention and arousal
- vesicular monoamine transporter (VMAT)
- monoamine oxidase and cytosoli catechol o methyltransferase
- metabotropic (alpha and beta )
neurons from the motor cortex ________ at the caudal medullary pyramid to innervate the contralateral side of the body
decussate
what cells provide scaffolding for the nervous system, take up potassium, provide glucose, and can regulate neurotransmitters?
astrocytes
What is the ventral anterior region involved in
what is its input from
where is its output
what does a lesion here cause?
- initiation and planning of movement
- basal ganglia
- premotor cortex
- akinesia (loss of voluntary movement)
there are three divisions to proprioception, describe them and where they project to
- conscious (learning new motor skills/plasticity)- goes to somatosensory cortex
- unconscious (reflex control)- goes to spinal cord
- unconscious (reflexes and motor control)- goes to cerebellum
what process shares a similar mechanism to long term potentiation but actually does the opposite and can reverse long term potentiation?
describe the process
- long term depression
- usually involved in low frequency, constant stimuli
- activates nmda receptors, but instead of secondary cascade of kinases that brings more ampa receptors to the surface, it activates phosphatases that internalize more ampa receptors
name some physical exam findings consistent with nonproliferative diabetic retinopathy
- dot blot hemorrhages, microaneurysms, exudates, macular edema
CSF is made in the ______
describe the flow of CSF
blockage of CSF can lead to _____
- choroid plexus
- lateral ventricles –> interventricular foramen –> third ventricle –> cerebral aqueduct –> 4th ventricle (lushka and magendie) –> taper into central canal
- hydrocephalus
how many nodes of ranvier must a local anesthetic block in order to block the entire axon?
what kind of neuron would this be easier to do?
3 nodes
small unmyelinated neurons
for idiopathic intracranial hypertension:
what demographic is most commonly affected
what is the largest risk factor
name clinical manifestations
- women of childbearing age
- obesity/weight gain
- headache, visual blackout, pulsatile tinnitus, enlarged blindspot
what affect does leptin have in the hypothalamus, and which nuclei have receptors for it?
what would happen if you had a leptin receptor deficiency
- will reduce appetite
anterior, lateral, paravenricular and arcuate nuclei
would gain weight af because your appetite is never supressed
huntington’s disease to do to a ______ repeat and is due to neurodegeneration of ______
what can you use to treat it and what does it do
CAG
striatum to globus pallidus external
haloperidol, dopamine antagonist, will help try to decrease threshold of activation for indirect pathway so it can function more
describe rachischisis
- neural folds fail to fuse (type of spina bifida)
where are the first order neurons of trigeminal afferents present? what is the one exception?
where do the neurons go after?
- trigeminal ganglion (outside of cns)
- proprioception first order neuron cell bodies are in mesencephalic nucleus in midbrain
proprioception neurons –> mesencephalic trigeminal nucleus (midbrain)
fine touch/pressure neurons –> main sensory trigeminal nucleus (pons)
pain and temperature neurons–> spinal trigeminal nucleus (medulla and spine)
what 2 swellings does the prosencephalon eventually form
telencephalon and diencephalon
if the convolutions of your cerebral cortex are very small, what is this called?
what clinical manifestations is this associated with?
microgyria
- mental retardation and physical defects
what separates the frontal lobe from the parietal lobe?
central sulcus
medially situated motor neuron pools in the ventral horn innervate ____ muscles and are involved more in ______
laterally situated motor neuron pools in the ventral horn innervate ____ muscles and are involved more in ______
- proximal/trunk
- balance/posture
- distal limb
- fine motor movement
where do lower motor neurons originate?
where do they synapse?
- brainstem (cranial nerve nuclei)
- spinal cord (ventral horn)
- directly on skeletal muscle
what artery supplies the occipital lobe?
if stroke occurs in this artery, why do some patients manage to maintain central vision?
- posterior cerebral artery
- small portion of middle cerebral artery supplies portion of occipital lobe responsible for central vision, so some blood supply is maintained in a posterior cerebral artery stroke
if you want to test and superior rectus and inferior rectus, where should the patient look
- out and then up and down
describe the process by which glutamate is made and recycled
1) glutamine is brought into the presynaptic terminal via System A 2 Transporter (SAT2)
2) glutamine is converted into glutamate and transported into vesicles via Vesicular Glutamate Transporters (VGLUTs)
3) once glutamate is released into the synaptic cleft, it is either taken up by the post synaptic neuron or is taken up by astrocytes via Excitatory Amino Acid Transportors (EAATs)
4) glutamate is converted by into glutamine via glutamine synthetase
5) glutamine leaves the System N transporter 1 (SN1) and the process starts all over
anencephaly is due to what?
what is missing?
is this compatible with life?
failure of the anterior neural pore to close
some or all of the cerebral hemispheres
nah
describe the process of how ischemia leads to neuronal cell death
- ischemia –> decreased o2 use and increased lactic acid
- ion pumps fail –> k released into ecm and neurons get depolarized
- neurons release glutamate vesicles, which activate nmda receptors –> ca influx –> cell apoptosis triggered
what is kluver bucy syndrome
what is another disease that is similar and describe what is affected
- damage to amygdala, have sexually inapprorpiate behavior, loss of fear and anger, emotional flattening, hypermetamorphosis, oral tendency (explore things with mouth), can’t recognize faces
urbache- wiethe disease: bilateral calcification and atrophy of anterior temporal lobes, can’t recognize fear or anger
why is the cornea clear but the sclera is white
what is one function they both do?
both are made of collagen fibers, but cornea’s collagen fibers are very organized whereas sclera’s are disorganized, which causes it to be white
PROTECTION
what part of the brain contextualizes your emotion input and response based on what is socially appropriate
pre frontal cortex
describe the process in which vesicles are recycled after releasing NT
1) clathrin coats membrane and allows for significant invagination
2) dynamin pinches membrane off to form coated vesicle
3) auxillin and hsc 70 remove clathrin coating, making it ready to accept NT again
what is the major excitatory neurotransmitter in the cns; what kind of receptor is it; what is the reversal potential?
what is the major inhibitory neurotransmitter in the cns? what kind of receptor is it; what is the reversal potential
- glutamate; non-selective cation ionotropic receptor; reversal at 0 mV
- GABA; chloride ionotropic receptor, reversal at -70 mV
what are the three main symptoms of horner’s syndrome
name 5 causes
Is it a sympathetic or parasympathetic nervous system problem
miosis, anhydrosis( not sweating), and ptosis
apical lung tumor, dissected carotid body, tumor in cavernous sinus, stroke
sympathetic! (lose it)
what area of the brain is associated with the motor component of speech?
in what lobe is this area?
broca’s area
frontal lobe (think, it’s in the same area as motor cortex)
if a patient has right eye internuclear opthalmoplegia, what would happen if you asked the patient to look to the right? what would if you asked them to look to the left?
- if they looked to the right, right and left eye would function normally and move to the right
- if they looked to the left, left eye would move to left, but would be pulsating (nystagmus) and the right eye would not move (exotropia)
what is the name of the condition in which the convolutions of the cerebral hemisphere do not form?
what clinical manifestations occur
lissencephalia
mental retardation, seizures, muscle spasticity, failure to thrive
name the term for the stimulation of inhibitory neurons improve the precision of receptive fields as transmission ascends the neuraxis
lateral inhibition
what is autonomic dysreflexia?
- condition due to a spinal lesion above T6; any remotely aversive stimulus below the lesion can’t get sent up therefore sets off a sympathetic reflex arc, which will leads to vasoconstriction, aka htn, impotence,
how is csf reabsorbed
via arachnoid granulations
what part of the brain can you stimulate and decrease depressive symptoms? what system is this region of the brain a part of?
name other parts of this system that are heavily implicated in emotion
- subcallossal cingulate cortex
limbic system
- amygdala, hypothalamus mediodorsal nucleus of the thalaus, prefrontal cortex, basal ganglia
what is memory consolidation
when does it happen?
transfer of immediate or working memory into long term memory via repeated exposure
- transfer happens in slow wave sleep and stabilizing happens via REM sleep via synapses
what are the effects of local anesthetics on the heart?
- can decreased myocardial excitability and increase refractory period, treating some arrhythmias
- can also cause myocardial depression and hypotension and death
define a motor unit
what is the typical size
- a motor neuron and the muscle fibers that its axons innervate
TRICK QUESTION THEY CAN VARY EXTENSIVELY BASED ON NEED
what is the difference between classical conditioning and operant conditioning
what happens if you keep using unconditioned response without providing the reward?
- operant: behavior can be modulated based on consequence
- classical: you can pair unconditioned stimulus to a conditioned stimulus to illicit a response from the unconditioned stimulus
- extinction
What type of glial cell covers CNS neurons with myelin?
what is its PNS counterpart?
oligodendrocytes
schwann cells
what happens in capsular hemiplegia?
- lesion to internal capsule
caused defects in corticobulbar and corticospinal tracts
–> right sided body hemiplegia and right lower face paralysis and right tongue paralysis
what type of fibers go between different levels of the brain (ex: from cortex to brainstem)
- projection fibers
how many spinal nerves are there? name each section and how many belong to each
31 pairs
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
what is hyperopia
when the lens focuses and image behind the retina (eye is too short)
where are meissner corpuscles located?
what modality are they
are they rapidly or slow adapting
do they respond to high or low frequencies?
is their receptive field large or small
give an example of what they are useful for
- near epidermis
- tactile discrimination
- rapid
- low
- small
- rapid changing stimuli to skin, ex: movement of ball in hands with juggling, object slipping in hand
does the telencephalon and diencephalon come from the alar or basal plates
alar plates
what is the suprachiasmatic nucleus in the hypothalamus responsible for?
- circadian rhythm
- reproductive cycles
- receives direct input from the retina
what are gamma motor neurons and what is their purpose
- motor neurons that cause stretch of the intrafusal muscle spindle
- keeps muscle spindle taught so that it can tonically sense change in muscle stretch
what is responsible for color vision and acuity?
What is present abundantly more: rods or cones?
which one is more sensitive to light and good for night vision
where are cones located
- cones (Color Cones)
- rods
- rods
- fovea
what two swellings does the rhombencephalon eventually form
metencephalon and myelencephalon
where does the tectospinal tract originate; where does it project to
what is it’s purpose
what type of neurons are in this tract
- superior colliculus to cervical spine
- coordinate movement of head/neck with movement of eyes
- upper motor neurons
for giant cell arteritis:
what demographic is commonly affected
what are the common clinical manifestations
what lab values may be elevated
what test should you order? what treatment would you give? do you need a definitive diagnosis to start treatment
- elderly (>50)
- scalp tenderness, unilateral vision loss, jaw claudication, weightloss, fever, night sweats
- esr and crp
- temporal artery biopsy; give high dose steroids immediately, do not wait for biopsy
the alar plate eventually becomes ___ nuclei
the basal plate eventually becomes _____ nuclei
sensory (dorsal)
motor (ventral)
what process can the relationship between the AMPA and NMDA receptor explain?
explain the relationship
long term potentiation
- NMDA receptor usually senses baseline negative potential and binds Mg in order to prevent entry of Na+; when glutamate binds to AMPA, Na rushes into cell and then Mg dissociates once the internal potential becomes more positive; then NMDA will bind glutamate and let Na in; this will also cause more AMPA receptors to be inserted into the membrane
if you perform the weber test and the patient lateralizes to the right ear, what two scenarios could cause this?
right sided conductive hearing loss
OR left sided sensorineural hearing loss
what part of the spine has lateral horns?
which horn, dorsal or ventral, relays sensory information? what about motor information?
- thoracic
- sensory- dorsal
- motor- ventral
“Stupid DMV”
neurons from the motor cortex decussate at the caudal ________ to innervate the contralateral side of the body
medullary pyramid
what hemisphere of the brain is associated with emotional inflection of speech?
what hemisphere is associated with happy emotions, what would happen if you had a lesion/stroke here?
what hemisphere is associated with negative emotions?
- right
- left, depression
- right
what is argyl roberston pupil/dorsal midbrain pupil
what can cause it
- damage to pre-tectal nucleus causes loss of light reflex in both eyes but doesn’t affect pupillary constriction due to accomodation (completely different mechanism)
- syphillis, tumor, hydrocephalus
what two function does the ciliary ganglion control
- pupillary constriction and accommmodation of lens
what are the four mechanoreceptors of tactile discrimination
meissners corpuscle
merkel’s disc
ruffini corpuscle
pacinian corpuscle
what are the main unconventional neurotransmitters? name two of them
what is unconventional about them
- cannabinoids: anandamide, 2AG
they aren’t prepackaged in vesicles; they can travel backwards and forwards; made from membrane lipids as a result of increase ca influx, can block presynaptic ca channels
describe the indirect pathway (from caudate/putamen to thalamus/cortex)
1) putamen/caudate spiny neurons receives significant input from cortex and fires GABA to globus palludius externus
2) globus pallidus externus now cannot inhibit its target, the subthalamic nuceli
3) the subthalamic nuclei send positive signal to the globus pallidus which sends inhibitory signal to thalamus to the keep their respective nuclei that go to the cortex inhibited
in adults, can thalamocortical neurons be modified?
no, only intracortical neurons/pathways
what are the first targets in the cortex for mitral neurons ? (4)
- amygdala
- olfactory tubercle
- entorhinal cortex
- pyriform cortex
describe the function of wide dynamic range neurons and where they are
- in the lamina II of the dorsal horn/substania gelatinosa
- when alpha delta pain fiber (fast initial pain), it will synapse on wdr and cause it go up to the brain stem
- however there are also inhibitory neurons that can inhibit the alpha delta fiber (like rubbing on your hand, wdr can resond to touch)
- HOWEVER, cfibers (which is that longer burning pain) can act on inhibitory interneurons that inhibit the original interneurons
can glucose make it across the blood brain barrier
yes through GLUT 1 transporter
what is the cranial pathway (2) for bringing general visceral afferents back to he brainstem?
- glossopharyngeal from head neck, abdomen and thorax goes to petrosal ganglion and then to nucleus solitarius
- vagus from GI, heart and bladder goes to nodossal ganglion and then to nucleus solitarius
describe the pathway from wanting to voluntarily turn your gaze to the right to actually doing it
- front left eye fields cross and synapse at paramedian pontine reticular formation (PPRF), then synapse at abducens nucleus
- for the right eye, then the abducens nerve travels to the lateral rectus
- for the left eye, the medial longitudinal fasciculus goes from abducens nucleus to occulomotor nucleus, and then occulomotor nucleus goes to the medial rectus
what are the three types of receptors for proprioception
- muscle spindle
- Golgi tendon organs
- joint receptors
define absolute threshold
the weakest amount of stimulus necessary that can be detected 50% of the time
what is the pathway for olfaction
- first olfactory receptor cells (neurons) detect the odor, go through cribriform plate to glomerulus inside of olfactory bulb and synapse; then mitral cell synapses with the glomerulus and travels through olfactory tract (periglomerular and tufted cells can synapse on mitral cell to increase specificity
- goes to central areas like amygdala, pyriform cortex,, entorhinal cortex, and olfactory tubercle as well as primary olfactory cortex
what protein is necessary for both ventral and dorsal spinal cord identity as well as neuronal differentiation in the cns?
retinoic acid
where are peptide neurotransmitters made? where are small neurotransmitters made?
which type of neurotransmitters is usually docked at the membrane and can be released with only one action potential?
- peptide: made in cell body with vesicles
- small: precursors made in cell body and final form made in the terminal
small nt’s (constantly used and released, peptide nt’s need more than one ap)
how can the hypothalamus be divided?
anterior, thalamus, posterior
medial periventricular, medial, lateral
What is the lateral geniculate nucleus involved in?
what is its input from
where is its output
what does a lesion here cause?
- vision
- optic nerve
- primary visual cortex
- contralateral homynomous hemianopsia (contralateral half visual field lost in both eyes)
describe the vistibular reflex pathways
1) input from vestibulocochlear nerve goes to the vestibular nuclei; sends some projects to the eye
2) vestibular nuclei sends projects down
lateral vestibulospinal tract (goes to every level of spine for posture)
medial vestibulospinal tract (goes to cervical spine to control compensatory head movements based on body position)
what is the difference between saccade and pursuit and vergence
what are they all
ways to shift gaze
- saccade is a quick movement of your eyes to a fixed target (200 msec delay)
- pursuit is a slower movement of watching a moving target (ex: a plane)
- vergence is adjusting axis for each eye based on the different distances of the target from the person
describes the pathophysiology of an adies tonic pupil
what condition is it similar to? how do they differ?
what can cause this?
- damage to ciliary nerve which carries both accommodating and pupillary constricting fibers; fibers regrow abnormally, and now you get no light reflex and sustained accommodating near reflex
- argyl robertson pupil/dorsal midbrain pupil, difference because adies tonic pupil is usually unilateral and has a sustained near response
- diabetes, autoimmune conditions, idiopathic
does the back have dense receptor regions or less dense receptor regions
do they have large or small receptive fields?
why
- less dense receptor regions
- large receptive fields
doesn’t need fine detail stimuli on a regular basis
what is presbycusis?
is it sensorineural or conductive?
age related hearing loss
sensorineural (lose hair cells as you age?)
what neurons have the fastest onset? slowest onset?
pain and autonomic neurons
motor neurons
what is an encephalocele?
- a type of neural tube defect/hernia in which brain contents protrude out of a congenital opening of skull
what type of hearing loss do hearing aids help?
what do they do
conductive hearing loss
amplify sound
name 3 functions of the ciliary body
- zonules suspend the lens
- ciliary body produces aqueous humor
- accommodation
describe the pathway for somatosensory neurons in the head
- V1, V2 and V3 travel to trigeminal ganglion and have cell bodies there (proprioceptive neurons exception, cell bodies in mesencephalic nucleus)
- fine touch/pressure fibers go and synapse at the main sensory trigeminal nucleus in the pons
- pain and temperature fibers descend to medulla/spinal cord and synapse at spinal trigeminal nucleus
- (proprioceptive nuclei go to mesencephalic nuclei where their cell bodies are )
- both fine touch and pain/temp pathways cross midline and ascend together as the ventrotrigeminothalamic tract and synapse in the VPM (thalamus); this neurons travel to primary somatosensory cortex and synapse
what are the two main inhibitory neurons; where are they located?
- GABA- located everywhere in the CNS at inhibitory and also some major neurons like basal ganglion
- glycine- brainstem and spinal cord
where along the cochlea are low frequencies deflected by the basement membrane? what about high frequencies?
low- apical end
high- basal end
describe the pathway of the corticobulbar tract from the motor cortex to the brainstem
what are the two exceptions
1) start with layer 5 pyramidal neurons that travel through the internal capsule and cerebral peduncle to the brainstem
2) synapses at bilateral cranial nerve nuclei for V, VII, Ix, X, XI, XII, pontine nuclei, red nucleus, reticular formation
hypoglossal nuclei and lower half of face only receive innervation from contra lateral side
the _____ (higher,lower) the pk, the slower the onset of a drug. why?
higher
- more of the molecule is in the ionized/charged form
in prolonged ischemia, what neurons are most at risk
what happens in intracranial pressure?
- glutamatergic CA1 neurons in the hippocampus, amygdala, striatum, frontal cortex etc (consume the most o2)
- intracranial pressure increases and causes edema due to increased co2, if you hyperventilate you can prevent this
describe the synapses that occur from the hair cell all the way to the auditory cortex?
does lesions at any level usually cause deafness?
1) stereocilia are bent and K sensitive cation channels allow K to enter the cell, depolarize the cell, and release neurotransmitters to the spiral ganglion
2) spiral ganglion neurons travel with auditory nerve and synapse in ventral cochlear nucleus (brainstem)
3) 2nd order neurons cross contralaterally via the trapezoid body to the superior olive and synapse
4) 3rd order neurons ascend (lateral lemniscus) to the inferior colliculus (midbrain) and synapse
5) 4th order neurons ascend to the medial geniculate body (thalamus) and synapse
6) 5th order neurons go to primary auditory cortex (superior temporal gyrus) and synapse with 6th order neurons
- no because afferents distribute bilaterally
what is one and a half syndrome?
what causes it?
intrnuclear opthalmoplegia when gazining one direction, horizontal gaze palsy when looking in the other direction
when looking in one direction, eyes won’t move (horizontal gaze palsy), and then when turning the other way only one eye moves (exotropia) with nystagmus of the normal eye
medial longitudinal fasciculus and paramedian pontine reticular formation (PPRF) are very close to each other, so a lesion to one can also cause a lesion to the other (mlf contralateral to pprf is affected)
what is brown sequard syndrome?
what deficits will you get
- usually due to occlusion of posterior spinal artery, only one side though, usually in cervical region
- depend on how much of spine dies, if it’s minimal, then only ipsilateral fine touch affected at poitn and below, if further than that then contralateral pain and touch for that level and below
what cortex is in the pre-central gyrus?
motor cortex
define motor neuron pool
- the motor units that innervate the same muscle
what is the most common neuropeptide neurotransmitter? what is it used for
- what is the primary ligand
what receptor is it common co-located with?
- opioid peptides, analgesia
- enkephalins
- GABA
give examples of light touch modalities
in general are the axons big and myelenated or small and unmyelenated
- proprioception, tactile discrimination
big and myelenated
what is the basal ganglia composed of
what is its function
- dorsal striatum: caudate and putamen
- ventral striatum- nucleus accumbans and olfatory tubercle
- globus pallidus, subthalamic nucleus, substantia nigra
- motor control, emotions, executive functions
what two parts of the basal ganglia are the starting point for regulating motor movement and what movements do they regulate?
dopaminergic neurons that modulate the basal ganglia come from what structure
caudate: eye and head movement
putamen: limb and trunk movement
substantia nigra pars compacta
when does fissuration of the brain start? when are all the main gyri/sulci present?
month 4
month 7
from what parts of the brain does the hypothalamus receive inputs from before acting on a stressor? on what nuclei in the hypothalamus do these inputs come onto?
cortex, hippocampus, amygdala
- paraventricular nuclei then anterior and posterior
what lobe of the brain is particular good at spatial attention?
which hemisphere is better and why
what would happen if you lesions this hemisphere?
- parietal
- right, because it can register spatial attention in both and right and left whereas the left can only do spatial attention on the right field
- you would lose spatial attention on the left side
what are ester local anesthetics metabolized by?
what is it metabolized to?
plasma pseudocholinesterase
PABA
what is the main thing the amygdala does? what would happen if the amygdala gets lesioned
name the three parts of the amygdala and what they do
- process, judge, and produce response to fearful stimuli, if lesioned, you would no be able to recognize fear and would have riskier behavior
- medial –> processes smell
- basolateral –> take in highly processed info from cortex and association temporal areas
- central –> receives processing from the basolateral group and then projects to hypothalamus and reticular formation to produce emotional response
what parts of the ear are affected in conductive hearing loss?
middle or outer ear
what is the main rate-limiting enzyme of glucose metabolism in the brain?
how can it be modified during times of increased glucose/atp use?
- hexokinase
- can be brought to mitochondrial membrane and bind, which increases its activity
what is the window for thromboembolectomy devices
less than 8 hours from onset of symptoms
what are benefits of using lidocaine
what may be a draw back?
- low toxicity, low hypersensitivity potential, can be injected via any route
- potent vasodilator, so must be used with epi
the alar plates give rise to sensory derivatives, except in one scenario; name this exception?
dorsal part of alar plates give rise to part of rhombic lips, which eventually forms the cerebellum
at the level of the medulla, the roof plate thins out and forms the ____ and _____
- posterior medullary velum and choroid plexus of the 4th ventricle
describe symptoms of upper motor neuron syndrome
- hyperreflexia
- hypertonia
- positive babinski reflex
- spastic paresis
what pathway do light touch modalities like proprioception and tactile discrimination take?
dorsal columns
what muscle movements does vestibulospinal tract regulate
what muscle movements does reticulospinal tract
what do they both help facilitate
extension
flexion and extension
- posture and balance
what neurons have the fastest offset? slowest offset?
- motor neurons
- autonomic and pain neurons
what is the major site for histamine in the nervous system
what enzyme converts histidine into histamine
what transports it into vesicles
what enzymes break it down
what type of post synaptic receptors does it bind to
use of anithistamines in the cns woudl cause what
- hypothalamus
- histidine decarboxylase
- vesicular monoamine transporter
- monoamine oxidase and histamine methyltransferase
- metabotropic
- sedation (think of benadryl!)
the peripheral nervous system is derived from the _____
the central nervous system is derived from the _____
- neural crest cells
- neural tube
what are the 4 attributes of a stimulus that a sensory receptor must mediate/convey
modality/submodality intensity location duration MILD
describe the golgi tendon reflex
golgi tendon 1b afferents sense contraction –> synapse on inhibitory interneurons –> alpha motor neurons inhibited –> relaxation of muscle
–> inhibition of synergistic muscle –> relaxation of synergistic muscle
–> activation of antagonist muscle –> contraction of antagonist muscle
trying to bring system back to baseline
for the sympathetic nervous system:
what are the length of pre and post ganglionic neurons
what does each ganglion release
where do the nerves for this system originate
what does this system regulate
- pre are short and post are long
- pre: acetyl choline post: norepinephrine except for sweat glands release acetylcholine and adrenals release norepi &epi
- T1- L2/3
- fight or flight response, increase hr, dilate pupils, turn off digestion, turn of urination/defecation, increase sweating
what is a receptive field
specific region where a sensory neuron can respond to a stimulus
what influences the ectoderm to differentiate into the neural plate?
nodochordal process
what two local anesthetics are in eutetic mixture of local anesthetics?
lidocaine and prilocaine
name 3 things the parietal cortex is good at?
- spatial attention
- synthesizing multiple senses at the same time
- can send projections down to lower areas (feedback)
the amygdala influences ____ and ____ in the hypothalamus via ______ and _____
- emotions and fear
- stria terminalis and ansa peduncularis
what are the two main parts of the center of the vestibule called?
- two macula called utricle and saccule
utricle= horizontal movement
saccule- vertical movement
(horizontal and utricle have more syllables
the auditory cortex is _______ organized, meaning each part of the cortex responds to different frequencies.
the motor and somatosensory cortexes are ______ organized, meaning each part of the cortex corresponds to a different body part
tonotopically
somatotopically
describe the flexion- withdrawal reflex
- polysynaptic
- group II, III, and IV afferent respond to averse stimuli (ex: pain) and synapse on multiple interneurons which synapse –> flexion of limb that experience stimuli and extension of other limb and inhibition of flexion on other limb
describe the sympathetic nerve pathway involved in horner’s syndrome
- start in hypothalamus, descend and synapse in upper thoracic/lower thoracic spine, travel along apex of lung, ascend along carotid body in superior cervical ganglion and into cavernous sinus and then travel to pupils, sweat glands, eyelids
where is the insular lobe located
what is it responsible for?
what would happen if you had damage to your insular lobe?
- deep in the lateral sulcus
- emotions, consciousness, regulation of homeostasis
- apathy, loss of libido
in the temporal lobe, what is the left temporal lobe good at doing
what is the right temporal lobe good at doing
- integrating faces and voices (superior temporal sulcus)
- recognizing faces (fusiform face area on the fuiform gyrus)
describe the pathway of the cortico spinal tract from the motor cortex to the spinal cord
what is the exception?
start with pyramidal neurons on the motor cortex that travel through the internal capsule, then cerebral peduncle, then basilar pons until it reaches the medullary pyramids, where it decussates and travels down the lateral funniculus and then synapses with a motor neuron or interneuron (lateral corticospinal tract)
a small subset of the neuron fibers don’t decussate and descend ipsilaterally down the anterior funniculus and synapse on the medial horn (ventral corticospinal tract)
where are pacinian corpuscles located?
what modality are they
are they rapidly or slow adapting
do they respond to high or low frequencies?
is their receptive field large or small
give an example of what they are useful for
- deep dermis/subcutaneous tissue
- tactile discrimination
- rapid
- high
- large
- touch when manipulating tools or hands on a steering wheel on a bumpy road
describe the path from hearing a word to then speaking a response
primary auditory complex –> wernicke’s area –> arcuate fasciculus –> broca’s area –> motor cortex
what is used to convert glutamine into GABA?
what is used to transport GABA and glycine into vesicles
- glutamic acid decarboxylase
- vesicular inhibitory amino acid transporters
what pathway do crude touch modalities like temperature and pain and coarse touch take?
- spinothalamic tracts
where does consolidation occur
where does memory storage occur
- hippocampus (medial temporal lobe)
- all over the neocortex
where are ruffini corpuscles located?
what modality are they
are they rapidly or slow adapting
do they respond to high or low frequencies?
is their receptive field large or small
give an example of what they are useful for
- dermis
- tactile discrimination
- slow
- low
- large
- detects stretch
when alpha motor neurons are stimulated to contract, _____ neurons are co-activated
gamma neurons
for acetylcholine:
describe it’s process of formation and breakdown
what are the two types of receptor it binds to and what function are they responsible for?
what disease is thought to involve acetylcholine pathways
- formed from acetyl coA and choline via choline acetyltransferase; broken down by acetylcholinesterase into acetate and choline
- nicotinic (ionotropic, 5 subunits)- motor control, pre-ganglionic neurons
- muscarinic (metabotropic, 7 subunits)- purposeful movement, sleep/wake cycle, attention (MuScArinic), parasympathetic action
- alzheimers
if you want to test the superior oblique and inferior oblique, where should the patient look
- in and then up and on (want to be parallel to muscle axis
what is myopia?
when the lens focuses an image in front of the retina ( eye is too long)
what would happen as a result of horizontal gaze palsy?
how would the gaze palsy differ if the lesion was in the left frontal eye field vs a lesion in the left pprf
- eyes would preferentially move in the opposite direction that you are trying to move your eyes (ex: if lesion is in left frontal eye fields, then you would preferentially move your eyes to the left)
- both would have
what separates the parietal lobe from the occipital lobe
parieto-occipital sulcus
describe the pathway of the vestibulo-occular reflex from the ampulla to the eyes
ex: turning head to left
left horiztonal canal is activated, sends action potential via vestibulocochlear nerve to the medial vestibular nucleus, synapses, then crosses midline and ascends to right abducen nucleus, synapses, aducens nerve activates right lacteral rectus muscle
- at the same time, neuron goes from abducens nucleus to occulomotor nucleus and synapses, and then occulomotor nerve innervates the left medial rectus
describe the pathway of gustation
- gustation neurons from VII, IX, and X synapse at the soitarious nucelus and then projec to the thalamus and then the insular and gustation cortices and can then also from there project to hypothalamus and amygdala
the visual cortex is near the _______ in the occipital lobe
the right hemisphere visual cortex receives input from the ____ visual field whereas the left hemisphere visual cortex receives input from the ____ visual fiedl
calcarine sulcus
left, right
what condition causes esotropia: abducen’s nervy palsy or internuclear opthalmoplegia?
abducen’s nerve palsy
if you had a lesion in the ventrotrigeminothalamic tract at the pontine level, what would be affected?
fine touch/pressure, pain sensation and temperature sensation
how do growing neurons and their axons find their target tissue?
using a growth cone that has filopodia and adhesion molecules that follow a chemotaxic trail of substrate/diffusable molecules
describe the golgi tendon organs
Group Ib afferent: rapid adapting, in response to stretch of tendon from muscle contraction ( is useful also for scenarios where you have to hold a position for a long time, prevents against fatigue)
the retina has a dual supply, name the two sources of blood supply
branches of the central retinal artery (what you see on funduscopic exam, inner) and choroid (outer)
what are the three types of motor units based on the types of fibers they innervate
(describe size of contraction, speed, and whether fatigable or not)
- slow: small force, contract slowly, fatigue resistant
- fast fatigue resistant: larger force, contract fast, fatigue resistant
- fast fatigable : large force, contract fast, fatigable
what are the two conditions related to issues with pyramidal neurons; describe the prolem
- down syndrome: loss of dendritic spines
- huntington’s: loss of layer 5 pyramidal neurons –> disconnection between cortex and brainstem
what is the difference between nociceptive and neuropathic pain?
nociceptive: due to noxious stimuli
neuropathic: due to injury or problem with neurologic structure (ex: nerves or cns)
what is post viral anosmia
what can help treat this ?
- mild or complete anosmia following infection of coronavirus, rhinovirus, epstein barr, or parainfluenza virus
- olfactory training
name three long acting anesthetics
BARTEr
Bupivicane (amide) Ropivicaine
Tetracaine (ester)
where are the two major sites in the brain that use dopamine and what are their functions
what enzymes is used to make dopamine
what transports dopamine into vesicles
what enzymes break down dopamine
what type of post synaptic receptors does dopamine bind to
- substantia nigra (movement) (parkinsons and schizophrenia)
- ventral tegmental area (motivation and reward)
- dopa decarboxylase
- vesicular monoamine transporter
- monoamine oxidase, cytosolic catechol o methyltransferase
- metabotropic
what does the lateral spinothalamic tract pathway bring
describe it
- somatosensory pain and temperature fibers
- goes through dorsal root ganglion and then travels up lissauer’s tract (lateral) and synapses higher up in the spinal cord, then travels across the ventral white commissure and continues up to synapse in the VPL (thalamus) and then synapse in the primary somatosensory cortex
pacinian corpuscles are an example of _____ adapting receptors
what causes this type of adaptive receptor
- rapid (respond to pressure, but turn off during duration)
- the gelatinous, lamellated layers aroudn the nerve energy dissipate energy quickly
what condition causes exotropia: abducen’s nervy palsy or internuclear opthalmoplegia?
internuclear opthalmoplegia
what neuron is responsible for regulating the synapse between bipolar cells and the photoreceptor cells?
horizontal cells
describe the pathway for fine touch discrimination/proprioception to reach the brain
- somatosensory afferent goes from receptor through the dorsal root ganglion to the dorsal column and ascends at either the gracilus fasciculus (lower body) or cuneate fasciculus (upper boady)
- ascends to the medulla, where it synapses, then decussates and becomes the medial lemniscus and travels up the vpl in the thalamus and synapses and then travels to the 4th layers of the primary somatosensory cortex and synapses
what taste receptors are ion channels and which ones are gpcr’s
- salty and sour- ion channel
sweet bitty and umami gpcr
describe joint receptors
- Group II: slow adapting, sense position and angle of joint, helps in making movement smooth
what part of the hypothalamus responds to increased body heat? what about decrease in body temp? Describe what a lesion to both regions would cause
What pathways bring information to and from these parts of the brain
anterior responds to increased heat from parasympathetics, causes dilation and sweating, (lesion would lead to hyperthermia)
posterior responds to decreased heat from sympathetics, causes shivering and constriction (lesion would lead to hypothermia)
- medial forebrain bundle brings info from the nucleus solitarius and to the hypot
- dorsal longitudinal fasciculus sends efferent fibers to brainstem
how does central renal artery occlusion present?
how can you treat
- sudden unilateral vision loss
- cherry red spot, hemorrhaging
veg f inhibitor
where do upper moor neurons originate
- motor cortex (premotor cortex and paracentral lobule)
- brainstem (superior & inferior colliculus, reticular formation etc)
what happens to cerebral blood flow and o2 consumption in those with arteriolosclerosis?
what about in those with neurodegenerative disease
- cerebral blood flow decreases but o2 consumption is constant (uses O2 more effectively)
- cerebral blood flow constant but o2 consumption decreases (less demand)
what are the three primary vesicles in the brain, and what parts of the brain do they correspond to
prosencephalon- forebrain
mesencephalon- midbrain
rhombencephalon- hindbrain
what are the two plexuses of the enteric nervous system and what do they do
what is a congenital disease where you lack these ganglion plexuses
as you age, what happens to your enteric nervous system
myenteric (aurbach)- musculature
meissners (submucus)- glands and chemical composition
hirschprung (get super constricted bowel and portion that is dilated)
- lose ganglions –> constipation, incontinence
name the three intermediate acting local anesthetics
LAMP Lidocaine amide Mepivocaine Prilocaine
what is the function of the cerebellum
what are the three lobes?
- smooth coordinated muscle movement (walking, balance standing, writing)
anterior, posterior, and flocculonodular
what is a necessary component of vision that is not directly involved in the neural pathway of vision?
what does it do?
retinal pigment epithelium
transports oxygen and nutrients from the choroid to the retina, prevents toxins from reaching the retina, degrades old photoreceptors, provides photoreceptors with vitamin a for visual cycle
what are the two main tracts for voluntary upper motor neurons
- corticospinal and corticobulbar tracts
what would happen to your emotions if you severed your hypothalamus?
straight up rage, no other emotions
describe the size principle of motor neurons?
motor neuron units are recruits in a fixed order according to size in order to generate a graded, increased force
(slow, then fatigue resistant, then fatigable)
what is primary hyperalgesia?
- decreases threshold for firing of pain nerve fibers
- will have increased firing of the nerve fibers, will have release of prostaglandins
- spontaneous firing even after stimulus is gone
what does the cuneocerebellar tract carry
describe the pathway
- non- conscious somatosensory proprioceptive fibers from C2-T4 to the cerebellum (ipsilateral)
- goes through DRG and travels up and synapses in the lateral cuneate nucleus in the medulla and then goes through the inferior cerebellar peduncle (restiform body) and synapses in the anterior and paramedian lobe
what is another name for a ligand gated ion channel?
what about g-protein coupled receptor?
which one is slow acting and which one is fast acting
- ionotropic (fast acting)
- metabotropic (slow acting because of secondary messenger cascade)
what is non-arteritic anterior ischemic optic neuropathy ?
how does it present
what are risk factors?
- neuropathy due to hypoperfusion
- monoocular painless vision loss with edema and hemorrhage
- small disc, hypoperfusion, small optic nerve, smoking, cholesterol, diabetes, htn
what is more likely to have symptoms: open angle or closed angle glaucoma?
what are those symptoms
- closed angle (since acute problem)
- vomiting, halos, bulging of dilated pupil
describes rapidly adapting receptors and slowly adapting receptors
- rapidly adapting (phasic)- respond to onset and offset, but not are off during the duration
- slowly adapting (tonic)- respond to onset, stay on during duration but taper a little, then turn off at offset
what is prosopagnosia?
- a condition in which you cannot recognize faces
- lesion in the inferior temporal cortex (fusiform face area
what is the term for the amount of nt in one vesicle
is calcium necessary for synaptic transmission or does it just modulate synapses?
quanta!
ABSOLUTELY NECESSARY (without it, nt’s don’t get released)
what is shy drager syndrome?
orthostatic hypotension without compensatory increase in hr
what glial cells are scavengers of the nervous system?
microglia
if you wanted to have a tonically contracted muscle that doesn’t require much force, what type of motor unit would you use
small slow motor unit
in optic neuritis, what type of visual defect is most common? what type of vision is most effected?
what are common manifestations?
- central scotoma
- color vision
unilateral vision loss, unilateral headache behind eye, painful eye movements
what channel do local anesthetics bind to; in which conformation? do they bind extracellularly or intracellularly?
are local anesthetics more likely to work in fast or slow neurons? why?
Inactivated Na channels
bind intracellularly
fast neurons, more likely to be in the inactivated state
how can middle ear injury or surgery affect taste?
- chorda tympani runs near that area, can get damaged and cause metallic taste
name from outside to inside the layers of the scalp to the cerebral cortex
scalp –> cranium –> dura mater –> arachnoid membrane –> subarachnoid space –> pia mater –> glia limitans –> cerebral cortex
Stupid Children Don’t Ask Stupid People (for) Grand Children
what eye condition causes painful eye movements?
optic neuritis
what are four common causes of chronic pain?
- cancer pain, cns disorder, nerve injury (neurpathic), musculoskeletal problem (nociceptive)
what are the four nuclei related to endocrine function in the hypothalamus and which pituitary do they release hormones to?
how does the anterior pituitary receive the hormones?
what hormones are sent to the posterior pituitary
PPAS
preoptic (anterior)
paraventricular (anterior and posterior)
arcuate (anterior)
supraoptic (posterior)
via fenestrated hypophysseal portal system
- vasopression and oxytocin
Are there more glial cells or neurons in the CNS?
glial cells!
what type of fibers go from one area of the cortex to another?
association fibers
most local anesthetics should be used with a _______
what are benefits of doing this? (3)
vasoconstrictor (epi, most anesthetics are dilators)
will improve anesthetic action, will decrease toxicity, will decrease chance of surgical bleeding
describe meningocele
can it cause impaired
- form of spina bifida in which the spinal cord is correctly in place but there is a protruding sac of meninges/fluid
- it can impinge on the dorsal and ventral root, but can be fixed
what is the least serious form of spina bifida?
describe it
spina bifida occulta
spine and meninges are in the proper space, but bone encapsulation of spine is not complete; hair may cover the skin covering
______ is a CNS mechanism that narrows and sharpens the original response to a peripheral stimulus
neural sharpening
brain development starts at week _____ from the ______
4
ectoderm (neural plate)
in hyperinsulinemic hypoglycemia, what are blood glucose and ketone levels
both are low (fatty acid metabolism inhibited in the liver)
mnemonic for functions of the hypothalamus
4 F’s
feeding
fighting
fleeing
fertility
what is hypoesthesia? what can cause it?
what is paresthesia? what can cause it?
- loss of touch, nerve damage or decompression sickness
- abnormal sensation, compression of nerve
what parts of the brain does the anterior cerebral artery innervate
frontal lobe, midline structures, and dorsal convexity
name 5 things that the brain stem is involved in?
- breathing regulation
- blood pressure regulation
- heart beat regulation
- eye movement and facial expressions
- houses nuclei for cranial sensory and motor nerves
what is amblyopia
how do you fix it?
lazy eye
- you should patch/cover the unaffected eye before the age of 2-3; this will cause an occular dominance shift to strengthen the connection of the lazy eye (however if you do this after the age of 2-3 it will never work because critical period has passed)
why do we have a loss of perception during sleep?
what is a situation in which this can happen when awake
- because thalamus neurons are demonstrating bursting- signaling which is not sufficient for transmitting information to the cortex for perception (as opposed to single spike firing)
- absence epilepsy, get seizure with eyes open, fluttering of eyes but staring off into space
what are the movements of the six extra ocular muscles?
superior rectus- up and in inferior rectus- down and in superior oblique- down and out inferior oblique- up and out lateral rectus- out medial rectus- in
_______ is the rate limiting step for the citric acid cycle in the brain
in hypoglycemic conditions, what happens to the citric acid cycle?
- pyruvate dehydrogenase
- high nadh levels will shut down pyruvate dehydrogenase, and pyruvate with be converted to lactate so that nadh can be converted to nad and be used for glycolysis; also amino acids will be used for energy
what are age related changes in the lens and ciliary body that causes difficulties with accommodation and seeing things close?
presbyopia
what is glaucoma
what are the two types? which one is most common
which one can be treated by decreasing the amount of aqueous humor produced
an optic neuropathy associated with vision loss for which increased intraocular pressure is a large risk factor
- open angle (most common)- due to increased resistance at the trabecular meshwork, ah can’t drain
- closed angle- ah is blocked from going through normal pathway, causes acute increase in intraocular pressure
- open angle
what are the 4 components of the diencephalon? what are their functions?
thalamus- relay sensory and motor information, sleep and wake cycles
hypothalamus- releases hormones/involved in autonomic nervous system
epithalamus (pineal gland)- sense of small and sleep and wake cycles
subthalamus- motor control
why do you get referred pain? what pathway is involved
because visceral afferent fibers travel with somatic fibers and the brain cannot distinguish between the two
anterolateral pathway
do the fingers have dense receptor regions or less dense receptor regions
do they have large or small receptive fields?
why
- dense regions
- small receptive fields
fingers need fine detail
if you are missing a corpus callosum what is it called?
agenesis of corpus callosum
what is emmetropia?
when you have THAT GOOD VISION
name the 6 derivatives of the neural tube with their corresponding ventricle
telencephalon- lateral ventricle (cerebral cortex)
diencephalon- 3rd ventricle
mesencephalon- cerebral aqueduct (midbrain)
metencephalon- 4th ventricle (cerebellum and pons)
myelencephalon- (medulla)
spinal cord- central canal
how does mirror visual feedback work?
- stand in front of mirror with intact right hand in mirror
- visual input “tells” mind that left somatosensory cortex is where the right somatosensory cortex is, and then when you uncurl your right hand so you’re higher cortical areas get rewired and perceive that amputated left hand is no longer curled
what is porencephaly
when does it occur
what can cause it
- cavity (pore) or cyst in the cerebral hemisphere; can have mental and growth retardation, seizures, paralysis, hypotonia
- can occur before or after birth
destructive lesion or developmental abnormality
what type of fibers go from one hemisphere to the other?
commisural fibers
what is the major site for serotonin in the nervous system
what does serotonin regulate
what transports it into vesicles
what enzyme breaks it down
what transports serotonin back into presynaptic terminal that is a target for anti depressents
what type of post synaptic receptors does it bind to
- dorsal raphe nuceli
- emotion, motor and feeding behavior, arousal, circadian rhythms
- vesicular monamine transporter
- monoamine oxidase
- SERT
- metabotropic and ionotropic
which local anesthetic can cause an allergic hypersensitivity?
what is it metabolized to that causes hypersensitivity
- anesthetics with ester groups (esters pester!)
- PABA
What is the medial dorsal nucleus involved in?
what is its input from
where is its output
what does a lesion here cause?
- memory, motivation, drive emotion, goal oriented behavior, maybe personality
- temporal lobe, amygdala, hypothalamus
- prefrontal cortex
- memory problems
What do D1 and D2 dopaminergic neurons do
D1 decreases the threshold for the direct pathway
D2 increases the threshold for activation of the indirect pathway
name the three centers of the hypothalamus involved in homeostasis/regulation of food
name the two bundles the bring info about feeding to and from the hypothalamus
- lateral hypothalamic area: appetitie, when stimulated you want to eat (lesion would cause anorexia)
- ventromedial nucleus: satiety, when stimulated you lose appetite (lesion would cause hypothalamic obesity
- dorsomedial nucleus: feeding, body weight, drinking
visceral info from GI goes to nucleus solitarius and then to hypothalamus via medial forebrain bundle
efferents leave hypothalamus via dorsal longitudinal fasciculus
what are the 6 divisions of the CNS from caudal to rostral?
spinal cord –> medulla –> cerebellum and pons –> midbrain –> diencephalon –> cerebral hemispheres
what part of the brain is required in declarative memory?
nondeclarative memory?
immediate memory?
working memory?
long- term memory
- medial temporal lobe (hippocampus)
- basal ganglia
- prefrontal cortex
- prefrontal cortex
- medial temporal lobe (hippocampus)
what does the dorsal spinocerebellar tract carry?
describe the pathway
- non-conscious somatosensory proprioceptive fibers from the lower body to the cerebellum
- goes through dorsal root ganglion and travels up to T1-L2, and synapses on a clark nucleus and then ascends laterally and ipsilaterally through the inferior cerebellar peduncle(restiform body) to innervate the anterior and parameridian lobe of the cerebellum
what is sudden infant death syndrome
problem with central autonomic network, get failure of respiration drive, get sudden increase in temp associated with periods of apnea
describe the process of one specific nucleus of the thalamus to the cortex to higher order thalamic nuclei
what are the three levels of the hiearchy of cortex
give an example of this via vision
- specific relay neuron projects from thalamus to layer IV of cortex, simultaneously non-secific relay neuron is projected to layer 1-3
- intercortical neurons project from IV to II/III and then to layer V, who sends one projection to VI, which sends a projection back to the original specific relay neuron in the thalamus
- also layer V pyramidal cell sends projection to modulator cell in higher order thalamic nuclei and the process keeps going from thalamus to cortex to higher order thalamus to higher order cortex
primary order cortex –> secondary order cortex –> association cortex
- lateral geniculate nucleus –> primary visual cortex –> pulvinar –> secondary visual cortex –> pulvinar –> visual association cortex
what is the organ of corti/what is it made of?
corgi’s are hairy!
- composed of one inner hair cell layer (main sensory receptors) and 3 outer hair cell layers (pre-amplifiers)
if you want to make a verticale saccade towards a fixed target, what path do you take
what about if you want to make a horizontal saccade?
if you are thinking of an imagined target or remembered target, what extra step is added
- from superior colliculus to contralateral midbrain vertical gaze center
- from superior colliculus to ipsilateral pprf to abducens nucleus to contralateral occulomotor nucleus
- input from frontal eye fields goes to ipsilateral superior colliculus
where are merkel’s discs located?
what modality are they
are they rapidly or slow adapting
do they respond to high or low frequencies?
is their receptive field large or small
give an example of what they are useful for
- near epidermis
- tactile discrimination
- slow
- low
- small
- can distinguish shape and form of objects in hands (curves and points and texture)
what is the region that will respond to a stimulus?
if you stimulate on a neuron outside of their region, what will happen?
- trigger zone
- NOTHING
mnemonic for afferent vs efferent
SAME
Sensory- Afferent
Motor- Efferent
In the midbrain, the alar plate gives rise to the______
the basal plate gives rise to the ______
superior and inferior colliculi
oculomotor and trochlear nuclei
what type of receptors/neurotransmitters excite in the pain pathway and facilitate the central modulation of pain
what type inhibit the central modulation of pain
- glutamate and asparate, nmda and non nmda receptors (ketamine can block this)
- GABA and glycine
describe lateral inhibition
- when a receptive field is stimulated, interneurons are activated also that inhibit input from the areas around the receptive field, which causes the receptive field to be more specific defined and the borders of the receptive field to be more defined
movement for cortex to the cortex can go via two pathways; what are they and how do they differ
- ventral system/path- sends characteristics/details about the stimulus
- dorsal- just cares about spacial characteristics
glucose is brought into the brain via the _____ transporter
GLUT 1
the ____ (more,less) myelinated and the ______ (larger/smaller) the diameter of a neuron, the lower the susceptibility of a local anesthetic to cause a block
give an example of a neuron like this
more myelinated
larger diameter
motor neurons
what is the prefrontal cortex responsible for?
executive functions (set of processes that all have to do with managing oneself and one’s resources in order to achieve a goal)
ex: personality expression, planning, decision making, social behavior
a ______ is a specific region where a sensory neuron can respond to a stimulus
receptive field
where are v snares located? name one; what toxin can block it
whre are t snares located? name 2; what toxin can block it
vesicle (V= vesicle); synaptobreVin (botulinum/tetanus toxin D,BFG, “Da BFG briefly snapped!”)
t= terminal
synTaxin (botulinum C), snap 25 (A and E, Robotic American Eagle Teens snapped 25 times)
what do astrocytes do? (5)
- provide scaffolding for nervous system
- take up excess potassium
- provide glucose
- regulate neurotransmitters
- induce endothelial cell tight junction formation
why does memory decrease as you age
what is one exception
- losing synapses and glial cells, not neurons
- alzheimers, lose neurons responsible in memory consolidation an storage
normally thalamic neurons that project to motor regions in the cortex are ______ ( inhibited/tonically active)
- inhibited because you don’t want to have spastic muscle movements when it is not necessary (also necessary for motions like sitting still)
describe meningomyelocele
- type of spina bifida where meninges and spinal cord are protruding out from the back, will cause motor and sensory impairment
what is a condition in which you have a cyst in your cerebellum
what are symptoms?
- dandy walker
- vomiting, large cranial vault, irritability, speech problems, vision problems, motor problems
if you get a stroke only in the cerebellum, which artery is the cause?
what if the brainstem is involved?
superior cerebellar artery
- pica or aica
