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268 Cards in this Set

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  • Back
what induces formation of the neural tube?
describe the formation of the neural tube, starting with ectoderm.
the ectoderm differentiates into neuroectoderm, those cells become taller creating the neural plate. the neural plate folds over to form the neural groove and later, neural tube.
in what direction does the nueral tube close?
it starts to close in the middle and then proceeds anteriorly and posteriorly.
what day does the cranial neuropore close? the caudal neuropore?
cranial: day 25

caudal: day 27
name the three brain structures which are developing during nueral folding, from rostral to caudal.
during week four of embryonic development, what is occuring in the neural canal?
the neural canal is differentiating. in the brain, it becomes the ventricles and in the spinal cord, it becomes the spinal canal.
how many basal laminas are present in the brain?
there is only ONE.
what occurs in embryonic development of the 5th week AND the 6th to 10th week?
5th: first differentiation of nerve cells, axons begin to migrate out of CNS.

6th-10th: intensive differentiation of stem cells into neural tissue.
which zone is along the basal lamina?
the marginal zone.
what types of cells develop out of the neuroectoderm?
what cell type gives rise to astroglia (astrocytes) and oligodendrocytes? what tissue are these derived from?
glioblasts, from neuroectoderm (from neural tube)
the ependyma cells are derived from what type of tissue? what cells do they give rise to?
they are from neuroectocerm (from neural tube) and they give rise to:
name one derivative of the intraembryonic mesoderm.
which gene is most involved with roof plate development? floor plate?
roof: BMP, bone morphogenic protein

floor: SHH, sonic hedgehog
where does the neural crest differentiate from? describe it's movement.
it differentiates from neural fold cells of neuroectoderm. it migrates into mesodermal area by ameboid movement, similar to mesoderm in general cells structure.
what type of cells does the neural crest differentiate into?
1.peripheral nerve cells (autonomic, sensory) cells (schwann, satellite)
4.adrenal medulla cells
what are some derivative structures of the neural crest? (6)
1.spinal ganglia
2.schwann cells of ventral root
3.sympathetic chain
4.adrenal medulla
5.preaortic ganglia
6.enteric nervous system
when is the neural tube induced by the notochord?
when does closure complete?
induction: middle of 3rd week

closure: late 4th week
what does the neural plate divide into?
ventricular, intermediate and marginal zone.
explain what each zone of the neural plate is responsible for and any additional divisions that occur.
ventricular: original cell source

intermediate zone: cell proliferation and differentiation. future gray matter.

marginal zone: future white matter

***intermediate divides into alar and basal!!
where does the ependyma come from?
the ventricular zone
what is the dorsal part of the intermediate zone called? what does it develop into?
the alar plate, develops into sensory areas.
what is the ventral part of the intermediate zone called? what does it develop into?
the basal plate, develops into motor areas.
what is the groove of the neural canal called? what does it separate?
the sulcus limitans, it separates the basal and alar plate.
describe the histological regions of the developing brain and what happens there.
intermediate zone: parts INSIDE. cell bodies differentiate, forms gray matter.

marginal zone: parts OUTSIDE. where axons grow and become myelinated, forms white matter.

ventricular: cells ADJACENT to central canal and ventricles, initial proliferative cells. develops into ependyma.
when is myelination within the CNS complete? when does it begin?
complete 2 yrs after birth.

begins at 16-20 weeks of intrauterine life.
what are some cytological (embryologic) modifications of the CNS?
fetal: cell death
postnatal: synaptic elimination.
how does the dorsal root ganglion develop with regards to the intermediate zone? the marginal zone?
the dorsal horn is from the alar plate of the int. zone.

the ventral horn is from the basal plate of the int. zone.
describe the position of the basal and alar plates in regards to the lateral sulcus.
alar = dorsal

basal = ventral
what structure develops into the inferior colliculus and mesencephalic nucleus of V?
the alar plate
name three structures the basal plate differentiates into.
the oculomotor nucleus
red nucleus
substantia nigra
describe the position of the somatic regions of the alar and basal plates.
the somatic regions are at extreme ends.

farthest dorsal quarter = somatic sensory

farthest ventral quarter = somatic motor
which parts of the alar and basal plates are adjacent to the lateral sulcus?
the visceral parts.
dorsal = visceral sensory
ventral = visceral motor
when does the spinal cord fill the canal?

where is the terminal end of the spinal cord at birth? in adulthood?
week 8

L3 at birth
L1 in adulthood
at seven months of fetal life, where does the spinal cord end?

how does the spinal cord grow in relation to the vertebral canal?

it grows SLOWER than the surrounding canal.
what causes spina bifida? describe what happens and any well-known variances.
it develops as a result of delay in closure of caudal neuropore.

late closure means mesoderm can't migrate and form lamina of vertebrae. spinal cord is unprotected.

hidden (oculta)
cyst of dura (cystica)
what are the last areas of the spinal cord to close?

what part is missing in spina bifida?
the thoracic, lumbar and sacral are last.

the dorsal arch of the vertebrae is missing.
what conditions which are similar to spina bifida can occur at the cranial end of the spinal column?
exencephaly and acrania
what are two major structures of the prosencephalon? which ventricles occur within the prosencephalon?
telencephalon and diencephalon.

lateral and third ventricle.
name seven structures that are derived from the prosencephalon.
1.lamina terminalis
3.lateral ventricle
4.interventricular foramen
7.third ventricle
what is the "midbrain' region called? what is contained within it?
mesencephalon. it contains several important nuclei and connects to the rhombencephalon.
what is contained within the rhombencephalon? where is it located?
metencephalon (pons and cerebellum)
myelencephalon (medulla)

most posterior part of brainstem.
what is the function of the pons? the cerebellum?
pons: connects medulla with midbrain, several important nuclei.

cerebellum: side-branch; major motor part of brain.
what is the function of the medulla?
connects brainstem to spinal cord. several important nuclei.
name the two flexures of the brain. where are they located?
cervical: btwn spinal cord and myelencephalon

cranial: at midbrain.
what is the germinal matrix? why is this important?
it's the thickening of the intermediate zone. all cells of the cortex differentiate from it.
describe the differentiation of the cortical cells.
cells of the cerebral cortex migrate through the marginal zone. there are three waves of migration, the second migrates through the first and the third migrates through the 1st and 2nd waves.

by 34 weeks the migration is complete and the germinal epithelium becomes a series of cortical nuclei adjacent to the ventricles.
what can be the site of hemorrhage in premature infants? what is it adjacent to?
the germinal matrix. adjacent to ventricles.
name six structures growing from the diencephalon.
4.mammilary body
5.pituitary stalk
6.optic chiasm
how are the caudate and lentiform nuclei separated?
by fibers of the internal capsule. they arise in the cerebral cortex, then head left to the brainstem.
describe the affects of acencephaly.
ACRANIA (failure of cranial end of neural tube to close during fourth week)

usually only prosencephalic structures are affected. (generally the telencephalon will always be affected, with more or less involvement of the diencephalon. brain stem may not be affected, or affected only mildly.)
what clinical malformation results in inadequate development of the brain, leading to small size?
microcephaly (multiple causes).
name a clinical malformation similar to spina bifida. what fails to close?
cranium bifidum

part of the cranium doesn't close
what is the most common cause of a blockage of cerebral aqueduct? what will happen if it's left unchecked?
hydrocephalus. fluid pressure builds up inside ventricles which cause the cranium to expand. it will crush the telencephalon if unchecked.
what parts of the brain contain the basilar pons and the cerebellum?
the metencephalon
where is the corpora quadrigemina found?
the mesencephalon
where would you find the hypothalamus and thalamus?
the diencephalon
name two structures found in the telencephalon.
the cerebral cortex and hippocampus.
where would you find the inferior olive?
the mycelencephalon (part of the medulla).
what is produced during the 4th week of growth as the brain bends?
the midbrain and cervical flexures.
unequal growth between the midbrain and cervical flexure leads to creation of this structure:
the pontine flexure. (divides the hindbrain into caudal - myelencephalon- and rostral - metencephalon -)
what does the cervical flexure eventually demarcate?
the level of the superior rootlet of the first cervical nerve.
where do the following structures originate from:
red nucleus
trochlear nucleus
basal plate
what structure does the inferior colliculus come from?
the alar plate.
where is the pineal body attached? where does it project? what is it?
it's attached to the posterior superior diencephalon.

it projects posteriorly into a CSF space btwn midbrain tectum inferiorly and the posterior end of corpus callosum superiorly.

what does the pineal gland secrete? what sort of innervation does it receive?
it secretes melatonin (more at night).
it receives afferent fibers, most abundantly sympathetics.
how is the pineal gland involved in X-rays?
a calcified pineal gland was considered an important landmark. it develops calcified concretions (brain sand) with age. in young people it may suggest pineal tumors.
what is found at the posterior end of the dorsomedial surface of the thalamus near the pineal?
a small area, the habenular trigone with a bump, the habenula.
what is the major afferent bundle to the habenular nucleus?
the stria medullaris thalami which arches across the dorsomedial aspect of the thalamus.
what is the stria medullaris thalami?
the stria is a complex bundle of inputs from a variety of structures and regions which are mostly 'limbic' in nature.
what structure transverses the upper wall of the pineal stalk?
the habenular commisure.
what is the midbrain tectal nuclei involved in?
the visual system, especially eye reflexes.
where is the pineal gland found?
the epithalamus
what are the sequential components of the brainstem? what is the prominent posterior (dorsal) part of the brainstem?
medulla, pons and midbrain are the sequential parts of stem.

the tectum is dorsal.
what are the three parts of the diencephalon?
hypothalamus, epithalamus and thalamus
what does the 3rd ventricle lie between? what is it's anterior wall called and what does it contain?
it's between the thalami and surrounds the massa intermedia.
ant. wall = lamina terminalis
includes anterior commisure.
what are two components of the epithalamus?
the pineal gland and posterior commisure.
name two parts of the hypothalamus.
the mamillary bodies and pituitary stalk.
what is a major landmark just rostral and inferior to the hypothalamus?
the optic chiasm.
name the large white matter tract arching over the thalamus.
the body of the fornix.
what separates the right and left ventricles?
the septum pellucidum
what structure lies in the dorsal wall of the pineal stalk?
the habenular commisure.
what sorts of afferent inputs does the stria medullaris thalami carry?
olfactory, limbic and hypothalamic.
what sort of structure does the pineal gland project into?
a large subarachnoid space
explain how a pineal tumor works.
it compresses the midbrain tectum (rostral part is visual) which in turn closes the cerebral aqueduct. symptoms of hydrocephalus result (increased CSF pressure) along with eye movement disorders.
describe the positioning of the posterior commisure. what is it involved in?
it attaches between the ventral wall of the pineal stalk and the midbrain tectum near the junction of the 3rd ventricle and cerebral aqueduct. it's involved in the visual system.
what are some properties of neurotransmitters?
1. must be synthesized within the neuron
2.stored locally
3.released into synapse
4.bind receptor on post-synaptic cell
5.inactivated after brief time
what is acetylcholine composed of? what types of receptors does it have?
choline and acetyl Co A

nicotinic and muscarinic receptors
what happens after Ach is released from presynaptic vesicles?
Ca2+ influx into terminals.
Ach is hydrolyzed after release by acetylcholinesterase.
what is another name for the central sulcus? what does it divide?
rolandic fissure

it divides the frontal from the parietal
what is the parietal occipital boundary?
medially: parieto-occipital sulcus

laterally: imaginary line from upper end of parieto-occipital sulcus to preoccipital notch.
what are the temporal lobe boundaries? (slide #7)
lat sup: separated from frontal and parietal lobes via lateral sulcus

lat post: separated from occipital lobe via parieto-occipital line and from parietal lobe via extension of lateral fissure to parieto-occipital line.
name the gyrus surrounding the end of the central sulcus. what lobes does it interconnect?
the paracentral lobule. it interconnects the frontal and parietal lobes.
what is brodmann area 4?
primary motor cortex, mostly precentral gyrus.
what are brodmann areas 3, 1 and 2 considered?
the primary somatosensory cortex, most of the postcentral gyrus. (the surface/top of the gyrus is 1, with 3 and 2 forming the banks on either side)
what is the precentral gyrus responsible for?
it's the primary motor cortex (BA 4), voluntary movement control.

lower half laterally = lips, tongue, larynx, face and hands.

upper half laterally = arm, trunk and hip

medial gyrus = foot, leg and thigh.
what sorts of nerves are related to the precentral gyrus?
large pyramidal neurons: BETZ cells give rise to many of the CORTICOSPINAL TRACT axons
what does a lesion to a part of the precentral gyrus cause?
PARALYSIS of the corresponding body part.
what is the only vertically oriented frontal gyrus? the only vertically oriented parietal gyrus?
frontal: precentral gyrus

parietal: postcentral gyrus
how do the pre and post central gyri interconnect?
they 'spill over' the medial surface and interconnect around the end of the central sulcus. they are linked by the paracentral lobule (post = post part and pre = ant part)
explain the primary somatosensory cortex.
aka the postcentral gyrus and BA 3, 1 and 2.
3 borders central sulcus
2 borders postcentral sulcus
1 is intermediate
major player in sensory perception.
what innervation is the postcentral gyrus responsible for?
lower 1/2 lat: receives lips, tongue, larynx, face and hands.

upper 1/2 lat: receives arm, trunk and hip

medial gyrus: receives foot,leg, thigh and genitals.
what does a lesion do part of the postcentral gyrus cause?
ANESTHESIA in corresponding body part.
where is BA 6 and what does it do?
it's just rostral to the precentral sulcus. the upper part is the SUPPLEMENTARY MOTOR cortex while the lower is the PREFRONTAL MOTOR cortex. they are both involved in limb and eye movements.
what area is rostral to BA6? what is it's function?
BA8 is rostral to BA6, it's the FRONTAL EYE FIELD, involved in VOLUNTARY eye movement.
what is broca's area?
BA 44 & 45, the middle part of the inferior frontal gyrus. it's an important speech center,especially on left side.
what does a lesion to broca's area cause?
aphasia (impairment or loss of speech)
what is the arcuate fasciculus?
the connection between broca's area and wernicke's area.
what is the prefrontal association cortex? where is it?
it's the remainder of the lateral frontal lobe (not BA6, 8, 44 or 45). it's involved in thinking, planning, understanding.
what do association cortices do?
they receive input from other brain areas, analyz and or modify before sending it to motore and or other association areas.
what is BA22?
much of the superior temporal gyrus, auditory association complex.
what is wernicke's area? what does a lesion of this area cause?
it's posterior BA22 (especially left side). processes hearing and speech for language comprehension. receives info from broca's via arcuate fasciculus.

lesion: inability to understand written or spoken speech.
what does the temporal pole correspond to?
primary olfactory cortex and limbic association cortex. processes smell and emotion (v.related)
how are BA17, 18 and 19 related?
BA17 is the occipital pole, a primary visual cortex where visual impulses from retinal arrive. 18 and 19 surround the pole in concentric circles (visual association areas). they continue around to the medial surface.
what separates the superior and inferior parietal lobules?
intraparietal sulcus
what is the visual association cortex?
the superior parietal lobule.
which gyri are within the inferior parietal lobule? what are their BAs? function?
angular gyrus (BA39) surrounds upper end of superior temporal sulcus

supramarginal gyrus (BA40) surrounds upper lateral sulcus

they are both association cortices for vision, reading and speech (recognize words)
what is the transverse gyri? where is it located?
aka gyri of heschl. BA41 (+/-42) is primary auditory cortex. located on the superior surface of the temporal lobe.
what is the planume temporale?
the smooth part of 22 located behind the transverse gyri (41/42). 22 = secondary auditory cortex, 41 = primary.
which gyri are located at the bottom of the lateral fissure? what are they surrounded by? explain their appearance.
insula (island of reill)

surrounded by circular sulcus.

there are several SHORT insular gyri ANTERIORLY
and one or two LONG gyri POSTERIORLY.
what is the insular cortex covered with?
frontal, parietal and temporal operculae.
which gyrus overlies the corpus callosum? how is it separated from the corpus callosum? what does it connect to posteriorly?
cingulate gyrus

callosal sulcus

parahippocampal gyrus via narrow isthmus
what does the cingulate sulcus separate?
the cingulate gyri from the gyri of the frontal and parietal lobe.
what forms the posterior limit of the paracentral lobule?
the marginal ramus.
what is the inferiormost gyrusof the frontal lobe, medially?
gyrus rectus
which two small gyri are tucked under the corpus callosum anterior to lamina terminalis? what is the area called? what is it involved with?
paraterminal (subcallosal) gyrus

paraolfactory gyrus

within the SUBCALLOSAL area

involved with olfaction and emotion (limbic)
what is the precuneus?
all of the parietal lobe btwn the marginal branch of cingulate sulcus and the parieto-occipital sulcus.
what does the calcarine sulcus divide? what is superior to it? inferior?
it divides the occipital lobe superiorly and inferiorly.

superior: cuneus
inferior: lingual gyrus
what is BA17? how are BA18 and 19 related?
the primary visual cortex. forms the border of the calcarine sulcus. 18 and 19 are visual association areas, they are on either side of 17 and make up the rest of the medial occipital cortex.
what binds the gyrus rectus laterally? what structure is lateral to this?
the olfactory sulcus.

orbital gyri (overly orbital plate of frontal bone)
what is the most medial gyrus of the temporal lobe? what is it continuous with?
the parahippocampal gyrus. it's continuous with the lingual gyrus.
what does the uncus overlie?
the amygdala
what gyrus is lateral to the lingual and is separated from the parahippocampal via the collateral sulcus?
the occipitotemporal gyrus
what separates the occipitotemporal gyrus from the inferior temporal gyrus?
the occipitotemporal sulcus
what are the BA areas of the inferior occipital and temporal lobes?
anterior 1/2 of parahippocampal = BA28 (primary olfactory cortex)

medial uncus = BA34 (limbic association cortex)
what does the anterior cerebral artery supply?
medial surface of hemisphere (back to parieto-occipital sulcus)

brs spill over onto lateral surface of longitudinal fissure
what is the uncus?
a medial projection of the anterior end of the parahippocampal gyrus.
what is the path of the middle cerebral artery?
it passes back through the lateral fissure to supply upper and lateral temporal loba, the insula and the most of the lateral surface (except strip along margin).
what is the path of the posterior cerebral artery?
it courses back between the cerebrum and cerebellum to supply the inferior temporal lobe and the medial and lateral surfaces of the occipital lobe.
define bundle:
give example.
collection of axons with well-defined origin, course, relationships and termination.
medial forebrain bundle.
define column:
3 large pillarlike bundles peripheral to spinal cord gray matter.
define lemniscus.
flat bundle of nerve fibers.
what is a stria?
small bunde of myelinated fibers. ie: stria medullaris thalami.
what is the corpus callosum an example of?
a commisure: structure carrying axons, generally interconnecting similar regions or structures across the midline.
what are association bundles? what are long association bundles?
association bundles remain within the hemisphere of origin and connect one region with another.

long association bundles communicate between lobes (short stay within a lobe).
define decussation.
tracts which start in one type of region of structure then cross the midline and end in a different kind of region or structure. (ex is decussation of pyramids, where corticospinal tract crosses in medulla).
what is a peduncle?
a structure which functions like a supporting stalk.
what connects the temporal and frontal lobes?
the uncinate fasciculus.
what does the inferior longitudinal fasciculus do?
courses from back to front, connecting the occipital lobe to frontal lobe in lower cerebrum.
which lobes does the superior longitudinal fasciculus cross?
temporal-occipital-parietal to frontal
where is THE arcuate fasciculus? which part of the brain does it arch in?
the posterior part of the large superior longitudinal fasciculus. it arches in the temporal region.
what does a specific/focal lesion to the superior longitudinal fasciculus cause?
problems of speech and language b/c it connects wernicke's area with broca's area.
what is the cingulum? where does it lie? what medical procedure is related to it?
it's an association bundle of the limbic system found deep to the cingulate and parahippocampal gyri.

CINGULOTOMY: tx for pain in cancer pts and for treating OCD.
where does the posterior commisure lie?
the transverse fiber bundle crosses the midline between the epithalamus and midbrain tectum. it's attached to the ventral wall of the pineal stalk above the cerebral aqueduct-3rd ventricle junction.
what is the fxn of the posterior commisure? what happens if it's injured?
it carries fibers from the:
midbrain tectum
pretectal area
habenular nuclei

carries fibers involved in EYE REFLEXES

injury: VERTICAL GAZE (looking upward)
where is the anterior commisure? what does it do?
it's a small round bundle interconnecting similar areas on opposite hemispheres. it crosses midline in the superior part of the lamina terminalis.

what does the anterior commisure connect?
middle and inferior temporal gyri
olfactory cortex
olfactory bulbs
what are the four parts of the corpus callosum? what is it's main fxn?
splenium, body, genu and rostrum.
it's formed by a majority of neocortical fibers involved in MIRROR IMAGE INTERHEMISPHERIC CONNECTIONS.
what does the splenium of the corpus callosum interconnect?
the occipital lobes. fibers bend sharply around to form the forceps occipitalis.
what is the narrowest part of the corpus callosum?
the body
which lobes do the genu connect? what structure does it make?
it connects the frontal lobes and the medial fibers bend sharply to make the forceps frontalis.
what is the rostrum continuous with?
lamina terminalis.
which parts of the corpus callosum are largest in cross section? why?
the splenium and genu are larger b/c the c.c. is not as long as the hemispheres; fibers are bunched anteriorly and posteriorly to accomodate the extra cortex.
what is a callosotomy for? what improvements have been made?
the surgical sectioning of the callosum is for intractable epileptic seizures, but it produces 'split brain' syndromes: can't say what's seen in left visual field b/c visual goes to right brain and verbal control is in left side.

sparing splenium minimizes this side effect.
which part of the c.c. is most responsible for epileptic seizures?
the anterior callosum (ie frontal lobes)
where is forceps minor found? forceps major?
minor: frontal lobes

major: occipital lobes
what does agenesis of the corpus callosum produce:
disconnection syndrome
what is the corona radiata?
projections received by the cortex (from lower brain pathways) which form a crown. the crown narrows inferiorly to make the internal capsule, passing between large gray matter nuclei called the basal ganglia.
where is the basal ganglia found?
the central part of the cerebral hempisphere.
what is the centrum semiovale?
fibers of the corona radiata intersecting with in the core of the hemisphere with fibers of the other systems (ie superior longitudinal fasciculus and callosal fibers)
describe the internal capsule.
a sheet-like structure containing various kinds of fibers including ascending thalamocortical fibers and descending corticothalamic, corticospinal and corticobulbar fibers.
why is the internal capsule a 'capsule'?
b/c it encapsulates the lenticular nucleus (with the external capsule which is just lateral to the lentiform nucleus).
describe the position of the internal capsule.
it passes btwn the lentiform nucleus laterally and thalamus and caudate nucleus medially. it's continuous with the corona radiata superiorly, crus cerebri in the cerebral peduncle of the midbrain inferiorly.
what are the three divisions of the internal capsule?
anterior limb: caudate nucleus from lenticular nucleus.
carries thalamocortical fibers and corticopontine fibers.

posterior limb: separate thalamus from lenticular nucleus. includes corticospinal tract.

genu: bend btwn limbs. contains corticobulbar tract fibers.
where are long motor fibers found in the brainstem? long sensory?
motor: ventral side

sensory: separated into tracts coursing within the substance of the brainstem.
which tracts of the brainstem and spinal cord (white matter) are ascending? descending?
ascending: sensory
descending: motor
what are two principal integrative tracts in the brainstem?
central tegmental tract and the medial longitudinal fasiculus. they course longitudinally carrying fibers which interconnect and integrate multiple regions and nuclei.
what produces CSF? what is it's function?
CHOROID plexus of the four ventricles.

1. structural support
2. cushioning to the brain and spinal cord.
what are the components of the leptomeninges?
pia mater (right over the brain)
arachnoid (filmy layer OVER pia mater)
what are the layers of the dura mater?
periosteal layer (over bone)
meningeal layer:
falx cerebri and cerebelli
tentorium cerebelli
diaphragma sellae
which sinus draws off most of the CSF?
the superior sagittal sinus
what are two meningeal spaces?
epidural space (cranium and spinal cord, only truly present in spinal cord)

subdural space
what are cisterns? name the anterior and posterior cisterns.
large areas in subarachnoid space.
chiasmatic, interpenduncular, pontine.

superior, cerebellomedullary (magna)
which cistern is located laterally? in the spinal area?
laterally: lateral cistern

spinal: lumbar cistern
when doing a lumbar puncture, which cistern is utilized?
the LUMBAR cistern!
describe the passage of CSF flow.
choroid plexus of lateral ventricles to:
interventricular foramen of monro to:
3rd ventricle to:
cerebral aqueduct(of sylvius) to:
4th ventricle to:
median and lateral apertures (foramina of magendie and luschka) out.
what is papilledema?
swelling of the optic disk. can be due to increased intracranial pressure.
what can cause a subarachnoid hemorrhage? what are it's signs?
it's often caused by ruptured arterial aneurysm in base of brain (middle cerebral a.). it's common in trauma patients unconscious > 1hr.

SUDDEN onset, severe headache, stiff neck. signs of meningeal irritation.
what causes a subdural hemorrhage? what are some signs?
it's due to minor to severe head trauma, usually subdural veins rupture. SLOW. it can cross suture lines and common in alcoholics.
what characterizes an extradural (epidural) hemorrhage?
it usually follows traumatic rupture of middle meningeal a. or v.
fracture of squamous temporal bone can result in cut vessel.
can cross midline but NOT suture lines.
what are two causes of hydrocephalus?
1. physical: obstructive hydrocephalus. via tumors, hemorrhages, infections and genetic.

2.communicating hydrocephalus, via overproduction of CSF. due to impaired absorption by arachnoid villi. also due to venous insufficiency.
where are inside 'choke' points?
blocked cerebral aqueduct. lateral and medial apertures?
name two differences between the dorsal and ventral horns of the spinal crd.
the dorsal horns are narrower and almost reach the surface of the cord. the ventral horns don't and are more rounded.
how is the white and gray matter arranged in the spinal cord?
white matter is EXTERNAL (peripheral)

gray matter is internal.
describe the three white matter columns around the spinal cord.
the posterior column is singular while the lateral and anterior columns are continuous with each other.
what is the function of the fasciculus gracilis and cuneatus?
they convey proprioception, fine touch, and vibratory senses to the medulla oblongata where the axons terminate respectively in the nucleus gracilis and the nucleus cuneatus.
what connects the anterior columns of the spinal cord?
an anterior white commisure.
describe the dorsal column of the spinal cord from sacral to midthoracic & from mid-thoracic to cervicals.
sacral - mid-thoracic: dorsal column is ENTIRELY fasciculus gracilis

mid-thoracic - cervicals: dorsal column MEDIALLY is fasciculus gracilis and LATERALLY fasciculus cuneatus.
what are the two tracts of the spinal cord involved in voluntary somatic motor innervation? which direction do they go?
lateral corticospinal tract (LATERAL COLUMN)

ventral corticospinal tract (ANTERIOR COLUMN)

they are both DESCENDING.
what are the two major ascending sensory tracts associated with the ventral and lateral columns of the spinal cord?
1.spinocerebellar tract (outside edge, info to cerebellum)

2.anterolateral system (a/v to #1), carries pain and temperature info to brain.
what is the propriospinal tract?
a thin layer of white matter bordering the gray matter in all the columns. it's specialized for conveying fibers from one layer to another.
it carries fibers that are interconnecting segments of the cord.
where is the dorsal lateral tract? what's it used for?
the dlt (lissauer's) is a white matter cap of the dorsal horn. much of it consists of pain and temperature fibers which bifurcate and send ascending and descending brs. several segments before entering the dorsal horn.
which part of the spinal cord surrounds the central canal?
the gray commisure
which lamina forms the tip of the dorsal horn? the base?
tip: I

base: V & VI
which lamina is a major relay nucleus for pain and temperature? what is it also called?
lamina II, substantia gelatinosa
which lamina combine to form nucleus proprius?
III and IV
which lamina is considered to be within the intermediate zone? what types of cells does it contain?
lamina VII

it lies between dorsal and ventral horns and includes motor AND sensory
what is the most lateral part of lamina VII? where is it found and what does it contain? what else is found here?
most lateral: intermediolateral cell column, found T1-L2 (aka intermediate horn).
contains preganglionic SYMPATHETIC neurons.
where is the nucleus dorsalis found? what do the output axons of nucleus dorsalis form?
near the base of the dorsal horn.

the dorsal spinocerebellar tract.
where is the sacral autonomic nucleus (SAN)? what does it contain?
SAN is found in the sacral cord, in the lateral part of the intermediate zone.

it contains cell bodies of the sacral PREganglionic PARAsympathetic neurons.
what is lamina VIII involved in?
it receives many descending fibers involved in motor fxn.
what does lamina IX represent?
IX represents the cytoarchitectural areas containing somatic motor neurons whose axons exit the VENTRAL root to innervate voluntary striated skeletal mm.
what innervation is included in the cervical regions of lamina IX?
C1-C6, spinal accessory nucleus. SCM & trap.

C3-C5, phrenic nucleus. thoracic diaphragm.
at all levels, what is found in the medial part of lamina IX?
the medial part contains the motor neurons to the axial trunk mm.
what is found at the levels of the brachial plexus and lumbosacral plexus with regards to lamina IX?

brachial: C5-T1 & lumbosacral: L2-S3 are found the motor neurons to the mm of the limbs.
what is found in the sacral region of lamina IX?
it contains the motor neurons innervating the VOLUNTARY urethral and anal sphincters (Onufs nucleus).
how many posterior spinal arteries are there? anterior? where do they originate from? what feeds into these longitudinal arteries?
there are two posterior and one anterior spinal artery. they originate from the vertebral arteries superiorly near the foramen magnum. segmental feeder arteries supply them along their length.
what is the artery of adamkiewicz?
usually at lower thoracic or upper lumbar, one anterior feeder artery becomes esp important.
what are radicular arteries?
they are segemental bbr of the aorta near the interventricular foramina.
which arteries supply the ventral horn and lateral white column?
the anterior spinal artery gives origin to the SULCAL arteries which do this. (posterior supplies penetrating bbr to dorsal horn and column).
what is the arterial vasocorona?
the circumferential vessel that connects the a & p spinal aa. it gives penetrating bbr to the periphery of the lateral and anterior white columns.
what structures make up the dorsal medulla? laterally? ventrally?
dorsally: fasciculus gracilis (m) and cuneate fasciculus (l).

laterally: olivary eminence

ventrally: corticospinal (pyramidal) tracts w.decussation.
name the dorsal and ventral appearance of the pons.
dorsally: cerebellum covers it.

ventrally: pons is a large rounded bulge.
what structures are found dorsally on the midbrain? what cranial nerve is present?
corpora quadrigemina:
2 superior colliculi
2 inferior colliculi
(posterior to i.colliculi is CN IV, smallest)
where are the cerebral peduncles found? what do they include? what is the ventralmost part called?
they are found in the midbrain, they include the tegmentum and basis. ventralmost: crus cerebri
what emerges from the interpenduncular fossa?
CN III, oculomotor nerve
what are the three regions of the brainstem? how are the first and second separated?
dorsal to ventral:
tectum, tegmentum, basis.

tectum and tegmentum are separated via the ventricular system.
what are the three parts of the tectum AND their alternate names? which part forms the roof of the 4th ventricle?
midbrain tectum: quadrigeminal plate

pontine tectum: superior medullary velum

medullary tectum: inferior medullary velum (this is roof of 4th ventricle, separating from cerebellum)
what is the ventralmost part of the brainstem? name it's three divisions.

midbrain basis: corticobulbar, corticopontine and corticospinal fibers.

pontine basis: descending motor and pontine nuclei

medullary basis: smallest, only corticospinal fibers to it (pyramidal tract).
what is considered the central core of the brainstem? what is included in it?
tegmentum, a complex mix of gray nuclei and white tracts plus diffuse but vital neural tissue RETICULAR formation.

1.all cranial nerve nuclei
2.major sensory ascending tracts traverse here.
3.integrative tracts: MLF & central tegmental tract
name three cranial nerves which exit from the ventral brainstem.
III oculomotor: interpenduncular fossa

VI abducens: pontomedullary junction

XII hypoglossal: btwn pyramid and olive
describe embryonic organization of neuron groups.
sensory: DORSAL to sulcas limitans

motor: VENTRAL " "
how is the adult pattern of cranial nerve nuclei organized?
in the region of the 4th ventricle (pons & upper 1/2 of medulla), the plates fold outward to become the floor of the ventricle. alar plate becomes LATERAL. SVE (facial mm, mastication, palate, pharynx) and GSA (head and face sensation) cells migrate ventrolaterally.
how is the closed medulla identified? open medulla?
closed: lower 1/2, central canal is embedded.

open: upper 1/2, 4th ventricle overlies it like a lake.
what is the landmark for the inferior closed medulla? what other large sensory tract is found here?
key landmark: decussation of the pyramids.

spinocerebellar tract also found overlying ALS.

venterolateral to cuneate nucleus: spinal trigeminal tract and nucleus.

*bear paw*
what is the key landmark for the superior closed medulla?
internal arcuate fibers representing the sensory decussation (fibers from gracile and cuneate nuclei cross to form medial lemniscus).
when are the gracile and cuneate nuclei much larger than the tracts? what tracts are unchanged?
at the level of the superior closed medulla.

the spinal trigeminal tract (& nucleus), spinocerebellar and spinothalamic (ALS) tracts are UNCHANGED.
what is the motor nucleus of the 12th cranial nerve called? where is it found?
the hypoglossal nucleus, found in the superior closed medulla.
what is the key landmark to the open (rostral) medulla?
the inferior olivary nucleus resting on the corticospinal tracts (pyramids). also, the central canal is gone and the ventricular system is large and flared out (4th ventricle).
what are three tracts easily recognized at the open (rostral) medulla?
most ventral/biggest: medial lemniscus

middle: tectospinal tract

at top, below XII: MLF
what lies just ventral to the inferior cerebellar peduncle (restiform body)? what is medial to it? what is draped over the outside of the peduncle?
the spinal trigeminal tract and nucleus.

medial: vestibular nuclei

draped: cochlear nuclei
where do all the parasympathetics to the viscera come from?
the dorsal motor nucleus of X (rostral open medulla)
what is a landmark of the pontomedullary junction and caudal pons?
middle cerebral peduncle.
describe the progression of the pyramids with regards to the pontomedullary junction.
at the junction, they are just forming.

rostrally: pyramids are broken up as they move thru transversely oriented fiber bundles.

scattered throughout bundles: pontine nuclei.
bundles: pontocerebellar fibers.
what does horizontal orientation of the lemniscus mean?

what structure is mixed up with it medially, carrying auditory fibers?
it means the ALS is now at the lateral end of the lemniscus.

trapezoid body.
what cranial nerve nuclei are found btwn medial lemniscus and 4th ventricle? (caudally)
most dorsal and lateral to MLF: abducens (VI). fibers course directly ventrally.

venterolateral to VI is facial nucleus of VII.
describe the course of the facial nucleus.
course dorsomedially to loop around VI nucleus, making facial colliculus. they do this b/c nucleus is part of SVE component that migrated ventrolaterally (dragging it's fibers with it).

THEN ventrolaterally to enter 7th CN.
where is the central tegmental tract found? what structures are dorsolateral in the tegmentum?
it's found in the center of the tegmentum (thru pons and caudal midbrain).
dl: vestibular nuclei and spinal trigeminal structures.
what is a good landmark for the mid-pons?
good landmark in pontine tectum is superior cerebellar peduncle (brachium conjunctivum) forming sidewalls of ventricle.
which structures are retained in the midpons (as from caudal pons)? what is new?
pontine nuclei
transverse pontocerebellar and corticospinal fibers
medial lemniscus

NEW: lateral lemniscus (auditory)
what nuclei are associated with the tegmentum in the mid-pons?
associated with the trigeminal n. (V), ventral to superiocerebellar peduncle.

laterally: chief principal sensory nucleus
medially: motor nucleus.
what is characteristic about the rostral pons?
4th ventricle shaped like ginko leaf. central gray is associated with the ventricle.
what is the tectum in the caudal midbrain?
the inferior colliculus, a relay nucleus of the auditory system.
what is the periaqueductal gray? where is it found?
it's a cylinder surrounding the cerebral aqueduct in the CAUDAL midbrain.
where can you find the medial lemniscus and ALS almost vertically oriented?
the CAUDAL midbrain
describe the position of the trochlear nerve nucleus.
it's near the pontomesencephalic junction.

dorsal to MLF
adjacent to midline at junction of central gray and rest of tegmentum

fibers course dorsally, decussate and exit into trochlear nerve. ONLY NERVE TO ORIGINATE DORSALLY.
what are the supports of the cerebral hemispheres? what are they made of?
cerebral peduncles, part tegmentum (dorsally) and part basis (ventrally).
what is the substantia nigra?
a layer of pigmented gray matter on the venterolateral tegmentum.
what is the crus cerebri? what kinds of fibers make it up?
large white matter tract entirely made of descending morot fibers from cortex (midbrain basis).

middle 1/2: corticospinal and corticobulbar

medial 1/4: frontopontine

lateral 1/4: parieto-tempero-occipito pontine.
what is the tectum in the rostral midbrain?
the superior colliculus, an integrative nucleus of the visual system.
what is a large motor nucleus in the central tegmentum? where does it extend?
the red nucleus, it extends into the diencephalon
where is the Edinger-Westphal nucleus found?
in the pretectum, found in the rostral midbrain.
the initial sources of blood for all part of the brainstem come from ______?
the VENTRAL side
what are the principle ventral arteries of the brainstem?
vertebral a, basilar a, posterior cerebral a.
how is the basilar artery formed? what does it supply?
the vertebral aa unite at the medulla pons junction to form basilar a. it supplies:

basal and ventral tegmental pons.
what does the anterior spinal a supply? what else supplies this area?
asa supplies most ventral-medial medulla. vertebral a also supplies intermediate area laterally.
what is the blood supply for the dorsolateral medulla?
posterior spinal a caudally. PICA of vertebral a more rostrally (PICA originates at olive)
what supplies blood to the dorsolateral tegmentum? caudal midbrain? rostral midbrain?
dt: ant inf cerebellar a.

caudal: superior cerebellar a.

rostral: posterior cerebral a.