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387 Cards in this Set

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  • Back
what % of total neurons in the system are sensory and motor neurons? what about interneurons and projection neurons?
1%; 99%
where are glutamate mediated synapses found in the CNS?
dendritic spines
what allows for the large variety of proteins present in the CNS?
~5000 different genes in the nucleus and RNA splicing
what type of glial cell largely lacks polarity?
astrocyte
how do astrocytes communicate?
through gap junctions (connexin), and release of chemical transmitters
what is the energy requirement for glial cells compared to neurons?
glia has a comparitively lower requirement and function well under anaerobic conditions, while neurons have a very high energy requirement and must have OXPHOS
what is the major excitatory neurotransmitter in the brain? what's the problem with this?
glutamate, it can be neurotoxic when present in high levels
what are the two types of astrocytes and where are they found?
protoplasmic (type 1) - found in gray matter
fibrous (type 2) - found in white matter
what cells make myelin sheaths in the CNS? in the PNS?
oligodendrocytes, Schwann cells
what is the name of the phagocytic cells of the NS that are comparable to macrophages?
microglia
what is the function of radial glia?
present in the cortices during development and help guide migrating neurons to the appropriate place
a Schwann cell can wrap around how many axons? what about an oligodendrocyte?
one; up to 50
what are 2 roles of the Schwann cell other than myelination?
embedding of unmyelinated axons and acting as satellite cells to support dorsal root ganglion neuronal cell bodies
what is the difference in unmyelinated axons in the CNS as compared to the PNS?
CNS: they are NOT embedded in glial cells, but are in total contact with the extracellular space
PNS: they ARE embedded in glial cells
how many astrocytes are present compared to neurons?
10x
what is the blood-brain barrier and what is the role of the astrocyte in maintaining it?
BBB is formed from the tight junctions of the endothelial cells of the capillaries. signals from the astrocytic end feet help to induce the tight seal.
is there nerve generation in the PNS? what about the CNS? why or why not?
PNS: yes, active processes allow redevelopment and reinnervation of tissues from the damaged axon or nerve fiber
CNS: no, the regeneration process is actively suppressed by signals released from oligodendrocytes (such as nogo). reative gliosis and astrocytic invasion of areas of damage also inhibit this process
what is the role of glia in the AP/synapse?
to uptake glutamate and ions such as K to maintain gradients
what has to happen to glutamate in order for it to be taken back up out of the synapse?
it has to be converted into glutamine
when (prenatally or postnatally) are most of the neurons born? does the myelination take place? do most of the synapses form?
neurons: most are born prenatally
myelination: mostly postnatally
synapses: mostly postnatally
what is the reason for the overlap in the time periods of the stages of development in the NS?
different neurons and glial cells are born at different times and are therefore developing at different rates
when does neurulation occur?
2-5 weeks embryonically
when does neurulation occur? when does proliferation occur?
2-5 weeks; 5 weeks to 6 months postnatally
when does migration of neurons occur?
5-25 weeks prenatally
when does differentiation of neurons occur?
25 weeks to 6 months postnatally
when does synaptogenesis occur? what is also occuring at this time?
25 weeks to adult; apoptosis (30-60% of neurons die after they are born)
define gestation.
period of time between conception and birth
what is the time period called embryonic development?
first 8 weeks of development
what is the time period called fetal development?
3-9 months
what is delamination? what is it's role in NS development?
the process of a mixed population of cells forming 2 layers. delamination involves the conversion of epithelial cells into mesenchymal cells in the late 2nd week
what does the epiblast eventually form? hypoblast? trophectoderm?
E: all the tissues of the embryo
H: yolk sac
T: placenta
define gastrulation.
differentiation of cells of the epiblast into the 3 germ layers (endo/ecto/meso-derm)
when cells begin to move during gastrulation, where do they pile up first?
node
movement of cells inward during gastrulation allows for the formation of what? when is this?
primitive groove; just after 2 weeks
during gastrulation, which cells will become endoderm? mesoderm? ectoderm?
endo: cells that crawl in first and displace some of the hypoblast cells (displaced hypoblast cells will also become endo)
meso: cells that move in later
ecto: cells that stay on the surface
what does the inner cell mass become?
epiblast and hypoblast
what does the epiblast become?
the embryonic epiblast
what does the embryonic epiblast become?
endoderm, ectoderm, mesoderm
what 2 processes are involved in neurulation?
formation of the neural plate and formation of the neural tube
when does neurulation begin?
before the proliferation of the cells begins
what tissue forms the notochord?
the mesoderm at the midline
what provides the inductive signal for the development of the neural plate from the overlying ectoderm?
the notochord
as the neuroderm thickens and cells elongate, what begins to form?
the neural plate
the neural plate is the precursor to what?
all of the neural and glial cells of the CNS
where does the neuroderm separate from the mesoderm and endoderm?
at the midline/axial region
what is the shape of the neural plate?
broader at the anterior end (brain end) and narrower at the posterior end (spinal cord end)
what is the precursor to the CNS?
the neural tube
when are all of the major CNS structures set up by?
2-5 weeks
what 2 things does the PNS arise from?
the neural crest cells and placodes
what is placode development essential for?
development of the eye
what does the notochord help induce? what is this structure? when does this happen?
primitive streak, where the cells first start migrating inward at the doral midline, 18-19 days
what happens to the primitive streak?
it will elongate, become more prominent, and will become the neural groove
what is it called when the neural plate folds up and margins of the neural tube contact each other, allowing the structure to become invaginated and form the hollow neural tube?
primary neurulation
how does primary neurulation take place?
cells undergo massive shape changes: they go from being cuboidal/columnar and become pseudostratified
what happens to the cells at the midline and lateral regions of the neural tube? what does this do?
the cells become wedged. this allows the plate to buckle inward at the neural groove and also elevates the margins allowing them to fold together and meet each other at the dorsal midline (~4th week)
what happens when the margins of the neural tube meet?
the cells form tight cell-cell junctions at the dorsal midline to form the roofplate
what do cells in the neural tube form?
the CNS
what do neural crest cells form?
PNS (ganglia, glial cells)
what do neural fold cells become when they fuse?
the neural roofplate
when does primary neurulation begin?
day 21
TEST QUESTION FOR SURE:
where does fusion of the neural folds begin?
in the middle of the plate at the level of the 4th somite
what is primary fusion of the neural folds? secondary fusion?
primary: when the anterior/rostral ends begin to fold
secondary: spinal cord (posterior) fusion
when do anterior neuropores close? posterior?
ant: day 23-24
post: day 27
when does differentiation and segmentation of the neural tube take place?
at the same time as the formation of the neural tube
what has to happen in order for the constriction of the neural tube to take place?
there has to be an increase of pressure within the neural tube at the anterior end
what are the 3 vesicles that form along the anterior/posterior end?
forebrain or prosencephalon
midbrain or mesencephalon
hindbrain or rhombincephalon
what are the 2 flexures of the neural tube?
cephalic (1st): causes the forebrain to lie underneath the hindbrain
caudal (2nd): occurs at the level of the hindbrain/spinal cord junction in the same direction as the cephalic flexure
when do the 5 secondary vesicles form?
the 5th week
what secondary vesicles form from the prosencephalon?
telecephalon and diencephalon
what secondary vesicles form from the mesencephalon?
it doesn't undergo secondary division
what secondary vesicles form from the rhombincephalon?
metencephalon and myelencephalon
what does the telecephalon differentiate into?
cerebral hemispheres including the neocortex, the basal ganglia, and the hippocampus
what does the diencephalon differentiate into?
thalamus, hypothalamus, retina, and optic nerve
what does the mesencephalon differentiate into?
midbrain, tectum, segmentum, colliculi, monoemenergic neurons
what does the metencephalon differentiate into?
pons and cerebellum
what does the myelencephalon differentiate into?
medulla
where do the ventricles form?
inside of the neural tube
where do the lateral ventricles come from?
telencephalon
where do the third ventricles come from?
cavity of the forebrain
where do the fourth ventricles come from?
cavity of the hindbrain
where does the cerebral aquiduct come from?
cavity of the midbrain
what are the 2 divisions of the PNS and what are each composed of?
somatic: lower motor neurons and sensory neurons
autonomic: sympathetic, parasympathetic, and enteric
thickenings of the epithelial cells in the ectoderm lying outside of the neural plate which develop from placodes generate what?
sensory epithelia of the nose, inner ear, and lens
lens itself and ant pit gland
neurons of specific sensory ganglia in the cranial nerves
what are the 2 main types of neural crest cells?
cranial and trunk
where are the cranial neural crest cells located? what do they differentiate into?
extend from the diencephalon to the level of the 5th somite. periocular tissues and some skeletal elements of the branchial arches
where are the trunk neural crest cells located? what do they differentiate into?
extend caudally from the level of the 6th somite. dorsal root ganaglia, sympathetic ganglia, Schwann cells, satellite cells, and the adrenal chromaffin cells
what 4 things is the neural tube divided into?
2 dorsal, right and left, alar plates and 2 ventral, right and left, basal plates
what joins the 2 alar plates? what joins the 2 basal plates?
roofplate; floorplate
what kind of neurons are generated in the basal plates? alar plate?
lower motor neurons; interneurons that receive information from sensory neurons in the dorsal root ganglion
what is the name of the structure that forms between the basal and alar plates? when is this formed?
sulcus limitans; ~4th week
what are neural tube defects caused by?
failure of proper neural tube closure
what is the cause of anencephaly?
failure of anterior neural plate fusion in region 2
what is the cause of spinal bifida?
failure of neural plate fusion in region 5
what is the most frequently occuring permanently disabling birth defect in the US?
spinal bifida
what other condition do newborns with spina bifida often have?
hydrocephalus
supplementation of what nutrient in the maternal diet greatly decreases neural tube defects?
folate or folic acid
what is the name of the birth defect that involves the cerebellum protruding into the spinal canal?
Arnold-Chiari malformation
what is the difference between type 1 and type 2 arnold-chiari malformations?
type 1: often associated with syringomyelia
type 2: much more severe type, associated with myelomeningocele and hydrocephalus
what causes encephalocele?
a hole is the skull through which the brain protrudes or herniates
what is holoprosencephaly? what often accompanies this condition?
failure of brain lobes to separate to different degrees; midline facial defects (cleft lip/palate, cyclopia)
what causes cleft palate? what other structure can it effect?
problems in migration/differentiation of neural crest cells; may affect pituitary growth since the palate and the ant pit are derived from the same tissue
what are the 2 major phenotypes that are associated with fetal alcohol syndrome?
1: facial and other physical abnormalities (facial dysplasia)
2: growth retardation and neurodevelopmental abnormalities
what is induction?
the process whereby one cell population influences the development of another
induction of the neural tube in frogs is controlled by the "organizer" which is analogous to what structure in humans?
henson's node
what is the function of the organizer in nervous system development?
it is necessary and sufficient for inducing dorsal ectoderm to form neural tissue
what are the molecules of neural induction? what do these molecules do?
noggin, chordin, and follistatin; they block BMP signaling, which is responsible for turning ectoderm into epidermis. if this is blocked, the ectoderm turns into neural tissue
what is the action of BMP signaling?
they act through tyrosine-kinase receptors which activate signaling molecules called Smads
what kind of cell adhesion molecules are present in the neural plate ectoderm?
N-cadherin and N-CAM
what kind of cell adhesion molecules are present in the epidermis?
E-cadherin
what is the signal that differentiates the dorsal side of the neural ectoderm?
BMPs
what is the signal that is induced by the notochord in the floorplate to differentiate the ventral neural ectoderm?
Shh
what does Shh bind to? what does this molecule normally do?
a receptor called patched; patched normally holds and inhibits smoothened but once Shh binds it releases smoothened and causes downstream activation of Gli
a mutation in what gene is responsible for Greig's polycephalosyndactyly?
Gli
mutation in what gene can result in holoprosencephaly 3?
Shh
what molecules are responsible for inducing neural tissue with anterior character? posterior character (spinal cord)?
noggin/chordin/follistatin; retinoic acid, FGF, Wnt
what transcription factors are expressed in the embryo in a rostral-caudal axis?
hox genes
what is the name of the area of neuroepithelium in which proliferation occurs?
the ventricular zone
vertical cleavage in the ventricular zone results in what? what about horizontal cleavage?
vert: 2 identical stem cells
horiz: 1 stem cell and 1 migrating neuron
what is a neuron's birthday?
when it undergoes it's last S phase and withdraws/migrates away
when does symmetric division at the ventricular zone begin? asymmetric division?
day 28; day 42
when is the greatest production of neurons?
day 42 - day 125
where are cortical neurons generated?
the pseudostratified ventricular epithelium, aka the proliferation zone
what is the pre-neurogenic phase? neurogenic interval?
pre: cell mitosis in the pseudostratified ventricular epithelium serves only to increase the number of cells in the proliferation zone
neurogenic interval: after some critical mass of cells has been produced, cells begin to migrate away from the PVE to take their place in the cortex
when do glial cells usually differentiate?
after neurons are born
how do neurons reach their final destinations during migration?
they "climb onto" radial glia which direct them to their final position
when do many cells reach their final position after migration?
between 3 and 6 months
the cortex develops in what manor?
inside out
what layer do the oldest neurons develop in?
VI
what molecule is responsible for the newborn neuron to stay stuck to it's radial glial guide?
reelin
what does reelin bind to?
low density lipoprotein receptors such as ApoER2 and VLDL receptor and megalin
what migration method is specific to the cerebral cortex?
radial glial cells
define somatic migration.
a neuron will put out a process to find it's way to it's final destination
what is PNS migration of neurons guided by?
adhesion molecules
what is apoptosis in the CNS due to? in the PNS?
CNS: competition for synapse formation
PNS: competition for growth and tropic factors
when is synapse formation most important?
postnatally
the axon growth cone contains what structures that sense the extracellular environment/cues and help guide the axon to it's final dendrite?
filipodia and lamellopodia
what is the name for groups of neuron cell bodies that are found within the CNS?
nuclei
what is the name for groups of neuron cell bodies that are found in the PNS? what is the exception to this?
ganglion, basal ganglion is the exception (it's in the CNS)
what is the name for axons that function together with a common origin and destination?
tracts/fasiculi
what is the name for a structural column that supports other structures?
peduncle
what is the name for a pathway that crosses sides of the brain staying at the same level?
commissure
what is the name for a pathway that crosses sides of the brain traveling to a different level?
decussation
what is the name for a white matter structure that connects the cerebrum to the brain stem?
capsule
what is another name for the dura mater?
packymenix
what is the collective name for the arachnoid mater, the subarachnoid space, and the pia mater?
leptomeninges
what is the name for the space between the pia mater and the penetrating blood vessel?
Virchow-Robin space
what is the name for the hole between the lateral ventricles and the third ventricle?
the interventricular foramen of Monroe
what is the name for the passageway that goes from the third ventricle into the fourth ventricle?
the cerebral aquiduct or the Sylvian aquiduct
what is the name for the lateral exits of the fourth ventricle? what about the medial exit?
lateral: foramen of Luschka
medial: foramen of Magendie
what is the name for the collecting area underneath the occipital lobe?
the cisterna magna
how is CSF returned to the bloodstream?
through arachnoid granulations
what does the telencephalon form?
cerebral hemispheres and the cortex
what does the diencephalon form?
thalamus and hypothalamus
what does the mesencephalon form?
the midbrain
what does the metencephalon form?
pons and cerebellum
what does the mylencephalon form?
medulla oblongata
what does the Sylvian fissure separate?
temporal lobe from the parietal lobe
what does the central sulcus separate?
parietal lobe from the frontal lobe
what does the parieto-occipital sulcus separate?
parietal lobe from the occipital lobe
what is the main motor cortex of the brain?
the pre-central gyrus
what is the main sensory cortex of the brain?
the post-central gyrus
what lobe is Broca's area located in?
the frontal lobe
what lobe is Wernicke's area located in?
the temporal lobe
what is Broca's area responsible for?
speech production
what is Wernicke's area responsible for?
language comprehension
what is the name of the gyrus that is dedicated to hearing?
Heschl's gyrus or the superior transverse temporal gyrus
what is the area of the temporal lobe that is responsible for short term memory and degenerates in Alzheimer's?
hippocampus
what is the name of the area responsible for emotions like anger and fear?
amygdala
what are the 2 glands associated with the diencephalon?
pineal and pituitary
what is the name for the place where enlarged thalami actually touch and obliterate the third ventricle?
the massa intermedia or the interthalamic adhesion
what 2 structures make up the lateral ventral portions of the midbrain?
the cerebral peduncles
what make up the corpora quadregemina?
2 superior and 2 inferior colliculi
what do the superior colliculi deal with? inferior?
superior: sight
inferior: hearing
what is the cerebellum responsible for?
fine motor integration
what is the name of the point in the medulla where many fibers pass from one side of the brainstem to the other? what's special about this point?
pyramidal decussation; you're leaving the spinal cord and entering the brain
what is the only CN that comes off dorsally?
IV
which CNs are midline?
I, II, III, VI, XII
which CN comes off as small rootlets between the olive and the pyramid?
XII
in the spinal cord, as you move towards the head, does the white matter to gray matter ratio increase or decrease?
increases
what are dorsal horns? ventral?
dorsal: sensory
ventral: motor
where is the gray and white matter in relation to each other in the brain? in the spinal cord?
brain: gray is outside and white is inside
spinal cord: white is outside and gray is inside
the white matter of the spinal cord is divided into what groups?
funiculi which contain fasciculi
what is the name of the midline fasicles of axons in the medulla?
fasciculus gracilis
what is the name of the lateral fasicles of axons in the medulla?
fasciculus cuneatus
what are the fasciculus gracilis responsible for? what about the fasciculus cuneatus?
both are responsible for the sensation of vibration and proprioception
FG: legs
FC: arms
where are the primary sensory neurons found?
in the dorsal root ganglion
what separates the dorsal and ventral rootlets of the spinal cord? what else does it do?
the denticulate ligament; stabilizes the cord laterally, may absorb CSF
what is the name of the cone at the end of the spinal cord?
conus medullaris
what stabilizes the spinal cord to the sacrum? what is it made of?
filum terminale; pia mater
what are the only 2 structures that allow you to observe the pia mater?
denticulate ligament and filum terminale
what is the name of the rootlets that come out in the lumbar cistern?
cauda equina
where does the spinal cord end in the adult?
L1-L2
what types of cells become mostly secondary sensory neurons in dorsal horns?
alar plate cells
what types of cells become mostly motor neurons in ventral horns?
basal plate cells
the 1st segment of the Laminae of Rexed isn't a layer. why? what is this segment called?
it is a pathway called Lissauer's tract and is lightly myelinated (it is NOT gray matter)
what is a syrinx?
when the central canal blows up, pushing on the ventral white commissure
what is the ventral white commissure responsible for?
carrying pain information from one side of the body to the other
when someone with a Chiari type I does a valsalva maneuver, what happens?
the central canal blows up, pushing on the ventral white commissure causing a loss of pain wherever the syrinx is
the lateral horn of the thoracic cord has what 2 additional structures? what do they do?
intermediolateral cell column: part of the sympathetic NS, preganglionic sympathetic neurons (only found in T1-L2)
Clarke's column: is a relay cerebellar nucleus
which part of the spinal cord has the most white matter?
cervical
what pathways synapse in the dorsal horn? in the dorsal column?
dorsal horn: pain pathways
dorsal column: dorsal column pathways (vibration and proprioception)
which part of the spinal cord has large ventral horns? why?
cervical, b/c there are lots of alpha motor neurons that need to go to the muscles of the arms
which part of the spinal cord has more gray matter than white? why?
sacral, b/c all the motor pathways have already left and the sensory pathways are just starting to come in
what is the extra "bump" in the sacral spinal cord called? what is it responsible for?
nucleus of onuf, goes to the sphincters
what is the name of the main descending/motor pathway? damage to this causes what?
corticospinal tract, damage causes paralysis
what kind of fibers does the ventral funiculus carry? why is this good?
motor pathways that affect trunk musculature with lots of redundancy, allows for maintenance of trunk muscles in case of a stroke
where is the lateral cortical spinal tract found?
in the dorsal part of the lateral funiculus
what is the difference between the LCST and the ventral funiculus?
LCST: only goes to one side
ventral funiculus: goes bilaterally to both sides of the trunk muscles
what are the 2 major sensory pathways? what do they carry?
the dorsal column and the spinothalamic tract, they carry modalities of vibrations and proprioception
what does tabes dorsalis (from syphilis) cause?
it destroys sense of vibration and proprioception
where do the fibers of the spinothalamic tract cross? what about the dorsal column fibers?
STT: immediately
DCF: at the caudal medulla
what are the prime modalities of the spinothalamic tract?
pain and temperature
is the dorsal column ipsilateral or contralateral? what about the spinothalamic tract?
D: ipsi
S: contra
damaging what artery can make parkinson's disease better?
anterior choroidal artery
what artery gets occluded in the majority of strokes?
the middle cerebral artery
if a person has a MCA stroke, what will the symptoms be?
they will be paralyzed on the side opposite of the lesion and have a hemisensory loss on the side opposite of the lesion
in a MCA stroke, the face is usually involved, but the forehead is spared. why?
the corticobulbar tract
what 2 diseases cause in situ strokes (aka, ischemic events)? what do these 2 diseases cause that lead to these events?
diabetes: accelerated athlerosclerosis
hypertension: vascular wall hypertrophy
from what part of the circulation does the opthalmic artery originate?
anterior
what is the name of the little piece of material that can end up in a retinal vessel and provide a warning of a future stroke in the normal opthalmic exam?
hollenhorst plaque
what is the name of the syndrome in which a patient complains of being light-headed when using their left hand? what is it caused by?
subclavian steal syndrome; they were born with stenosis in the subclavian artery before the vertebral artery
what does hemianopsia mean?
loss of one side of vision due to a posterior circulation stroke involving the cerebellum
what kinds of symptoms could result from a posterior circulation stroke?
abnormal eye movements, dizziness, vomiting, problems swallowing or speaking
what is a mural thrombus?
a blood clot that forms in the wall of the left ventricle due to a heart attack
where do most venous clots end up?
in the lungs
what should you look for when you see a stroke in an unusual patient?
a patent foramen ovale
what are the 2 types of echocardiograms? what are each used for?
transthoracic: used to look at the ventricles
transesophageal: used to look at the atria (in the back)
what are subcortical strokes usually associated with?
diabetes and hypertension
what part of the brain do the lenticulostriates supply?
the internal capsule (connects the cortex to the brainstem)
what does the posterior limb of the internal capsule do?
connects the pre and post central gyri to the brain stem
how will lacunae in the anterior limb of the internal capsule affect the body? what about the genu? what about the posterior limb?
anterior: no symptoms
genu: contralateral face paralysis
posterior: paralysis (espeically the anterior 2/3 of the posterior limb)
what is one way to differenciate cortical MCA strokes from subcortical lenticulostriate strokes?
MCA: may have aphasia (Broca's or Wernicke's area), usually motor AND sensory are affected, affected consciousness
subcortical: pure sensory or motor stroke, consciousness is not affected
what is an intraparenchymal bleed almost always caused by? what is the other cause?
Charcot-Bouchard aneurisms that burst (due to hypertension)
other cause: amyloid angiopathy (protein buildup)
what type of bleed is fast and usually involves the middle meningeal artery getting sheared?
epidural hematoma
what type of bleed is slow and involves the shearing of the cerebral bridging veins?
subdural hematoma
what usually causes subarachonoid hemorrhages?
leaking berry aneurisms
what is the usual patient presentation of a subarachnoid hemorrhage?
neck stiffness (blood leaking into the CSF) and headache
how do you tell if blood in a spinal tap is from a traumatic tap or a bleed?
traumatic tap: blood will clear from CSF as you get more samples
what is xanthochromia?
lysis of RBCs releasing hemoglobin into the CSF making it yellow
what is another name for the confluence of sinuses?
torcula
what drains the pituitary gland?
the cavernous sinus
the fornix is a white matter pathway important in memory called what?
pez's loop
what is the pigmented region that degenerates in parkinson's disease called?
substantia nigra
where is the locus caeruleus? what is it responsible for?
2 black spots, nucleus in the brainstem (pons), responsible for the physiological response to stress and panic
what fossa is CNIII in?
interpeduncular fossa
what is the name of the lines coming out of the obex?
sulcus limitans
what is another name for the insula?
isle of reil
what 2 gyri make up the inferior parietal lobule?
supramarginal and angular
the rootlets of what CN come out between the pyramid and the medulla?
CNXII
the rootlets of what CNs come out of the pontomedullary junction?
CN IX, X, and XI
what is the landmark for the caudal medulla?
pyramidal decussation
what does the pyramid represent?
the corticospinal tract, the main motor pathway
what happen to the fibers at the pyramidal decussation?
~80% cross over and end up in the lateral corticospinal tract, ~20% don't cross and end up in the ventral corticospinal tract
what would happen if the pyramids were damaged?
you would lose strength on the side that was damaged (LCST) but would still have innervation of the trunk muscles due to VCST being bilaterally innervated
what pathway is responsible for vibration and proprioception modalities?
dorsal column-medial lemniscus pathway
where are the primary sensory neurons located?
dorsal root ganglion
where do the dorsal column medial lemniscus fibers cross?
caudal medulla
what CN is present in the caudal medulla?
CN XII
what happens to the dorsal column medial lemniscus after it synapses?
it forms the medial lemniscus
what is the name of the arching fibers that come from the nuclei and make the medial lemniscus?
arcuate fibers
where are the fibers associated with pain in the face? what about pain in the body?
face: spinal nucleus/tract of V
body: spinothalamic tract
the spinothalamic tract crosses over in the brainstem via what structure?
the anterior white commissure
where are the primary sensory neurons of the trigeminal system located?
in the trigeminal ganglion
what is unique about the fibers of CNXI? what do they go to?
the fibers begin below the foramen magnum, go up through the foramen magnum, out the jugular foramen (not a true CN)
the fibers go to the trapezius and the SCM
what is the distinguishing feature of the rostral medulla?
the olive containing the inferior olivary nucleus
what is the name of the nucleus/tract in the rostral medulla that looks like an eye, stands alone, and deals with taste?
solitary nucleus/tract
what is the reticular formation responsible for?
heart rate, blood pressure, respiration
where is the dorsal motor nucleus of X located? what kind of nuclei is it?
between CN XII nuclei and the solitary nuclei/tract
autonomic (parasympathetic) nuclei - decreases heart rate and increases peristalsis
what does the inferior olivary nucleus do?
it is a cerebellar relay nucleus that sends sensory information to the cerebellum
what structure sends fibers down from a rostral region to synapse in the inferior olivary nucleus?
the central tegmental tract
palatal myoclonus is caused by what?
a lacune in the central tegmental tract as it's going into the inferior olivary nucleus
what is the only movement disorder that does not go away with sleep?
palatal myclonus
what does the dorsal motor nucleus of X go to?
it is a motor pathway that will go out to parasympathetic smooth and cardiac muscle
what does the nucleus ambiguous do?
carries alpha motor neurons that go to voluntary skeletal muscle in the throat (palette, pharynx, larynx)
what does CN IX innervate?
taste sensation, stylopharyngeus muscle, autonomic motor fibers to the parotid gland
what is the main function of the vestibular nuclei?
VN gets information from the inner ear about where the body is in space
which vestibular nuclei is the important one?
the lateral one
where is the area postrema? what is it responsible for?
it lines the floor of the 4th ventricle; it is the vomiting center
what is the anatomy behind the fact that a drunk person that is close to vomiting may have nystagmus?
the area postrema (vomiting center) is close to the vestibular nuclei (controls eye movements)
what is the tectospinal tract responsible for?
it causes head movement in the direction of light/sound (b/c it connects to the colliculi)
what do the pontine fascicles at the pontomedullay junction form?
the middle cerebral peduncle
where is the corticospinal tract found?
in the pyramidal fascicles
what is another name for the middle cerebral peduncle?
brachium pontis
what is another name for the inferior cerebral peduncle?
restiform body
what is another name for the superior cerebral peduncle?
brachium conjunctivum
what does the middle cerebral peduncle consist of?
pontine fibers that have crossed
what does the inferior cerebral peduncle do?
brings primarily propriocepive information and superior olive information from the opposite side into the cerebellum
what does the superior cerebellar peduncle do?
it's primarily the output of the cerebellum that allows the cerebellum to "talk" to the cerebral hemispheres
what is the important distinguishing feature of the caudal-most pons?
rootlets of CN VII and VIII
what are the 2 parts of CN VIII? what are each responsible for?
vestibular nucleus: balance
cochlear nucleus: hearing
what nuclei exhibits tonotopia? what is tonotopia?
cochlear nucleus
tonotopia: certain parts of the nucleus respond to a certain frequency of hearing. the deeper you go into the nucleus, the higher the frequency that is recognized
what does the CN VII innervate?
muscles of facial expression
what happens to your hearing if you get a lesion within one of the auditory pathways in the brainstem?
nothing - you don't lose hearing
what is the name for the hearing fibers that cross over to the other side of the pons?
the trapezoid body
what is the function of the superior olivary nucleus?
locate a sound in space
what is the function of the lateral lemniscus? medial lemniscus?
lateral: hearing
medial: vibration/proprioception from the body
what does CN VI innervate?
the lateral rectus of the eye
what CN exits in such a way as to cause a bulge in the floor of the 4th ventricle? what is the name for this bulge?
VII; facial colliculus
what are the 2 names used for when there is hemiparalysis with sparing of the forehead?
upper motor neuron VII, or a corticobulbar tract lesion
what is another name for Bell's palsy?
lower motor neuron VII
how are the 2 parts of the VII nucleus innervated?
top part: bilateral innervation
bottom part: ONLY contralateral innervation
what does the inferior salivatory nucleus innervate? superior salivatory nucleus?
inf: parotid gland
sup: every other gland
what are the 4 nuclei of the trigeminal complex?
spinal nucleus of V
main sensory nucleus of V
main motor nucleus of V
mesencephalic nucleus of V
what is the spinal nucleus of V responsible for?
pain and temperature to the face
what is the main sensory nucleus of V responsible for?
vibration and proprioception
what is the main motor nucleus of V responsible for?
main muscles of mastication
what is the mesencephalic nucleus of V responsible for?
neurons primarily go to the main motor nucleus; this is also responsible for the jaw jerk reflex
what are the 2 types of monoamines that are made in the pons?
endolamines and catecholamines
what is an example of an endolamine? what is it responsible for?
serotonin; responsible for mood and controlling pain
what are 2 examples of catecholamines? where are they made in the brainstem? what are they responsible for?
dopamine - made in the substantia nigra
noradrenaline - made in the locus ceruleus, fight/flight
what is made as a byproduct by any neuron that makes a catecholamine?
neuromelanin (black pigment)
what does the middle longitudinal fasciculus do? what is it assisted by?
carries information from the inner ear and connects it to CNs III and VI so that your eyes move together; parapontine reticular formation assists with this
what is the tegmental thalamic tract made of?
the main sensory nucleus of V and the spinal nucleus of V
CN IV is the only CN that does what 2 things?
exits ventrally and decussates
fibers from the frontal eye field go where and on what side?
the go to the contralateral paramedian pontine reticular formation
what does the paramedian pontine reticular formation talk to? what does it talk through?
ipsi6 contra3, through the medial longitudinal fasciculus
what 2 CNs work in concert to move our eyes in the right direction laterally?
III and VI
how does a lesion in the medial longitudinal fasciculus, between the nuclei of III and VI present?
as internuclear opthalmoplegia (look to one side and the eyes are normal, look to the other side and one eye can't move correctly)
what part of the brain are the inferior colliculi located? superior?
inf: caudal midbrain
sup: rostral midbrain
where is the nuclei of IV located?
below the cerebral aquiduct and above the medial longitudinal fasciculus
what does CNIII have riding along with it?
parasympathetic fibers that have their own blood supply
what does it mean to have a complete III lesion?
both motor and PS components of the nerve are knocked out
what is it called when a lesion spares the PS of III but knocks out the motor component of III?
a diabetic third
what is a diabetic third often a result of?
a berry aneurysm on the posterior communicating artery
what is anisocoria?
unequal pupils
what is the main landmark for the rostral midbrain?
red nucleus
what are the 3 corners of Mollaret's triangle? what are the pathways to/from each part of the triangle?
1- red nucleus
2- inferior olivary nucleus
3- dentate gyrus (of cerebellum)

1 to 2: central tegmental tract
2 to 3: inferior cerebellar peduncle
3 to 1: superior cerebellar peduncle
what happens when the central tegmental tract is damaged?
palatal myoclonus occurs
what does the posterior 1/3 of the posterior limb of the internal capsule contain?
sensory information going up
what kind of fibers go into the VPM?
fibers from the trigeminal thalamic tract
what kind of fibers go into the VPL?
arm and leg fibers from the medial lemniscus and the spinothalamic tract
what makes up the retrolenticular portion of the internal capsule?
optic fibers heading to the occipital lobe
what structure is severely defected in Parkinson's disease?
the substantia nigra
what synapses on the inferior colliculus?
inf: lateral lemniscus, which is headed up to Heschl's gyrus
what is the most medial nucleus of the CNIII nuclear complex? what does it innervate? what do lesions here produce?
Edinger-Westphal nucleus, innervates the pupil and the smooth muscle in the eyelid
lesions: ptosis and anisocoria
what is a fascicular third?
when a lacune knocks out only one of the fasciculi of CNIII, resulting in diplopia and usually due to diabetes
what is the anterior thalamic nuclei important for?
memory (limbic or papez's loop)
what is the dorsal tier of the thalamus involved in? what do lesions here produce?
limbic and personality; lesions don't usually cause symptoms
what is the seam of the thalamus called? what does it do?
interlaminar nuclei; allows all of the thalamic nuclei to talk to each other
what is the swelling in the posterior part of the seam of the thalamus called? what does it contain? what synapses here?
the central median nucleus; contains the VPL and VPM; main sensory pathways synapse here before going to the cortex
what nuclei is at the back end of the thalamus? what does it have on it?
pulvinar; 2 bumps: medial/lateral geniculate
where does the lateral geniculate go? medial?
lateral: occipital lobe
medial: Heschl's gyrus
where can a wire be placed to shut off untreatable tremors?
the ventral intermediate nucleus
what does the mamilothalamic tract connect?
the mammilary bodies with the anterior thalamic nucleus
in what nucleus can a wire be place in Parkinson's patients in order to treat tremor?
the subthalamic nucleus
what does the zona inserta contain?
pathways from the basal ganglia
what is the name for the beginning of the fornix?
fibrae
what connects the 2 temporal lobes?
anterior white commissure
what is the pleasure center of the brain?
the septal nucleus
what nucleus is associated with addiction?
the nucleus accumbens septi
what part of the brain degenerates in Alzheimer's disease?
the hippocampus
where does the medial part of the olfactory trigone lead? lateral? other exits?
medial: septal nuclei
lateral: rhinal cortex
other: hypothalamus
what structure lies below the fornix, connects the septal structures, and sends information to the amydala?
the stria terminalis
what is the lateral nuclei of the hypothalamus connected to?
feeding
what is the ventromedial nuclei of the hypothalamus connected to?
stopping feeding or satiety
what is the anterior and preoptic nuclei of the hypothalamus connected to?
heat sensing
what is the posterior nuclei of the hypothalamus connected to?
cold sensing (sympathetic) and sleep arousal
what is the suprachiasmatic nuclei of the hypothalamus connected to?
circadian rhythms
what is the supraoptic and paraventricular nuclei of the hypothalamus connected to?
neurohormones (oxytocin and vasopression)
what is the function of the reticular formation?
it wakes you up
what is the function of the pineal gland?
circadian rhytms
what is the name for the swellings of neurotransmitters in the axons of neurons of the hypothalamus?
herring bodies
what drains the anterior pituitary?
cavernous sinus
what is the simplified nernst equation?
60 log (out/in)
what does it mean for an action potential to be regenerative?
it can self-maintain and propagate faithfully without decay
what does it mean to be at the nernst potential?
it's the point at which diffusion is exactly balanced by the electrical potential
what is the term for the difference between membrane and nernst potential?
driving force
what is ohm's law?
V = IR
what does tetrodotoxin do?
blocks inward Na channels
what is the time constant equation?
T = rc
time = resistance x capacitance
what is the length constant equation?
lambda = Square root of(membrane resistance/internal resistance)
what disease causes progressive loss of PNS axons which causes weakness and atrophy?
Charcot-Marie tooth disease
what is epilepsy?
having more than 2 unprovoked seizures
what are the 2 types of seizures?
generalized and focal (partial)
what are 3 types of generalized seizures?
tonic-clonic, abscence, and myoclonic
what is a characteristic of abscence seizures?
3 spiking waves per second
what are some characteristics of frontal lobe seizures?
hypermotor and psychiatric manifestations
what are some characteristics of temporal lobe seizures?
long, smoldering seizures with a feeling of deja vu, amnesia
what are some characteristics of parietal lobe seizures?
somatosensory symptoms, body-morphing symptoms
what are some characteristics of occipital lobe seizures?
visual disturbance like micropsias, warping of a portion of the visual field, blocking out
what kind of seizures have the most potential of success with resective surgery?
temporal lobe seizures
how is the EEG generated?
by the flow of synaptic currents through a cell
name the four types of brain waves, each's range of Hz, and when they are seen.
delta: 0.5-3 Hz, sleep
theta: 3-7 Hz, sleep
alpha: 8-13 Hz, occipital lobe, relaxed wakefulness
beta: fast activity (>13 Hz), awake
name the 2 types of brain waves not seen on an EEG and their frequencies.
beta/gamma oscillations: 20-80 Hz
fast ripples: 250-500 Hz
what is another name for generalized abscence seizures?
petit mal seizures
what 2 things are related to an increased risk of seizures?
synaptic reorganization or sprouting, and increased amounts of NMDA receptors
what is Rasmussen's encephalitis?
rare, progressive pediatric epileptic syndrome due to inflammation of the brain