Week 1 Learning Issues Flashcards
3 vesicle stage
prosencephalon, mesencephalon, rhombencephalon
5 ventricles
lateral vesicle, 3 vesicle, mesencephalic aquaduct, rostral 4th ventricle, cd 4th ventricle
5 vesicles
telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon
brainstem
diencephalon, mesencephalon (midbrain), metencephalon (ventral metencephalon= pons), myelencephalon (medulla)
brain divisions 5
telencephalon, diencephalon, mesecephalon, metencephalon, myelencephalon
brain divisions 3
cerebrum, brainstem, cerebellum
cerebellum
dorsal metencephalon
cerebrum
telencephalon
functional divisions brain
forebrain, cd brainstem, cerebellum
forebrain
prosencephalon; telencephalon and diencephalon
cd brainstem
midbrain, pons, medulla oblongotta
brain development to formation of neural groove
- Neurulation -> neural tube
- Notocord -> overlying ectoderm thickening
- Neural plate forms
- Neural plate invaginate forming neural groove
brain development starting at ectoderm fusion
neural groove has just formed:
- tissues at junction of neural and non-neural ectoderm fuse dorsally starting at level rhombencephalon
- fusion progresses crly and cdly
- Neuropores near rostral and cd extent neural tube are last to close
- Vesicles are forming as tube is closing
- Neural tube and overlying ectoderm separate
Neural tube and ectoderm separate what’s next?
- neural tube and overlying ectoderm separate
- Neural tube is internalized as overlying skin forms
- Neural crest cells arise from cells at junction of ectoderm and developing neural tube and migrate throughout body
- Mesenchymal cell migration later in development
Mesenchymal cells appear later in development and do what
- mesenchymal cells derived from somites migrate D and V to NT between NT and ectoderm
- This forms meninges/ skulls/ vertebrea around CNS
spinal cord development vs brain development
spinal cord NT surrounds central canal and central canal stays relatively simple cylindrical canal for spinal cord development
for brain development have vesicles that -> ventricles; the neural tube surrounding each vesicle develops differently leading to 5 brain divisions
Mylencephalon development -> choroid plexus
- mylencephalon aka medulla oblongotta= associated with 4th ventricle
1. Start with neural tube, neural canal, sulcus limitans
2. D aspect NT (rohofplate) expands -> 4th ventricle
3. Alar plate develops laterally, not dorsally b/c rohofplate expansion
4. Lumen NT enlarges -> 4th ventricle
5. Choroid plexus develops in roof 4th ventricle
Mylencephalon development starting choroid plexus development
choroid plexus just developed in roof 4th ventricle
- Grey matter organized into nuclei with sensory or motor fxs associated with CNs; also diffuse neuron pops or nuclei associated with ascending and descending pathways
- Sulcus limitans divides alar and basal plates
- CNs VI-X and XII arise from medulla
- Bundles of white matter tracts develop as axons grow through brainstem
what CNs arise from medulla
VI-X and XII; nuclei associated with these CNs are in alar and basal plates
Alar vs basal plate
alar- sensory
basal- motor
where do sensory neurons develop in relation to motor in mylencephalon
sensory develop lateral motor develop medial
steps choroid plexus development
- ependymal cells of alar plate develop laterally as rohofplate expands
- Surface capillaries in close contact with ependymal cells of rohofplate form vascular structure = choroid plexus
- Choroid plexus secretes CSF and ventricles
- Choroid plexus develops similarly in 3rd and lat ventricles as it does in above described 4th ventricle
Metencephalon development 4th ventricle
- associated with 4th ventricle
- 2 regions pons and cerebellum
1. 4th ventricle extends into mesencephalon D to pons; roof = medullary vellum= ependymal layer derived from roofplate; no choroid plexus in medullary vellum bc no space, cerebellum overlies roof 4th ventricle dorsally
Pons in metencephalon
- Pons= rostral continuation myelencephalon, developes similar to myelencephalon
- Alar plate lateral to sulcus limitans, pontine sensory nucleus of CN V develops from here, this is not the pontine nuclei
- Basal plate = ventromedial; motor nuclei of CN V develops from this
what do you see on v aspect of the pons
transverse fibers of pons (metencephalon)
pontine nuclei
found in metencephalon
These are subpopulation of alar plate neuroblasts from pons which migrate ventrally to form the pontine nuclei ventral to the basal plate
Axons of neurons in pontine nuclei
found in metencephalon
neurons in pontine nuclei send axons up to cerebellum -> transverse fibers of pons on V aspect of metencephalon where they continue as middle cerebellar peduncles on lateral aspect metencephalon
Cerebellum development
found in metencephalon
- cerebellum develops D to Pons and 4th ventricle from proliferation of alar plate and unique population of cells from ependymal layers
- Cerebellar growth proceeds and comes to overlie myelencephalon and pons
patterns of grey matter organization cerebellum
- cerebellar cortex on surface
2. cerebellar nuclei embedded in white matter
white matter of cerebellum
deep to cerebellar cortex and surrounds cerebellar nuclei it contains axons traveling betweenn brainstem and cerebellar nuclei and cerebellar cortex
rostral, middle, and cd cerebellar peduncles
composed of axons traveling to and from cerebellum these anchor cerebellum to brainstem; middle cerebellar peduncle is from transverse fiber of pons
mesencephalon development
- grows dorsally; midbrain; mesencephalic aquaduct
1. Alar plate expands and grows D to rohofplate to form tectum
2. Neural canal is reduced to narrow tube= mesencephalic aquaduct
3. V to tectum alar and basal plates contribute to mesencephalic (midbrain) tegmentum = rostral continuation of medulla and pons
4. CN nuclei develop
5. Crus cerebra form v to midbrain tegmentum
4 dorsal prominences of tectum
rostral and cd colliculi (involved in vision and audition respectively)
choroid plexus and mesencephalic aquaduct
dorsal ependymal cells of mesencephalic aquaduct are surrounded by nervous tissue = no choroid plexus develops
CNs in msencephalon
motor nuclei of CN III and CN IV arise from basal plate neurons in mesencephalon
crus ceribri
form v to midbrain tegmentum; = made of axons traveling from cerebral cortex carrying mortar signals to brainstem and spinal cord
Diencephalon development
- associated with 3rd ventricle
- diencephalon rostral most pt of brainstem
1. Lumen NT expands vertically in median plane, lumen is compressed laterally by growth diencephalic neural tube
2. Interthalmic adhesion developes as 2 sides thalamus grow medially and partially fuse, this separates 3rd ventricle into D and V chambers
parts of diencephalon
epithalamus, thalamus, sub thalamus, hypothalamus
D->V
epithalamus
pineal gland; prominent in sheep and cats, small in dogs; involved in circadian/ circannual rhythms, limbic, and endocrine fx
thalamus
gateway to neocortex; heart shaped makes up a lot of diencephalon, sensory pathways other than olfaction fo through here
- interthalmic adhesion fuse both sides together
- thalamic neurons go into cerebral cortex via internal capsule
hypothalamus
lateral to ventral aspect of 3rd ventricle; neuroendocrine, autonomic, and homeostatic fxs
pituitary gland
(aka hypophysis) attached to v aspect diencephalon at hypothalamus
what forms posterior pituitary gland
ventral outgrowth of hypothalamus in development forms neurohypophysis (posterior pituitary gland)
what forms anterior pituitary gland
hypophyseal pouch extends D from stomadeum and contacts neurohypophysis and forms adenohypohysis (anterior pituitary gland)
Optic vesicle development
optic vesicles develop as evaginations from diencephalic vesicles will become retinala and optic nerve
3rd ventricle
In diencephalon
donut shape, divided into D and V chambers by formation of interthalmic adhesion
- Rostral extend 3rd ventricle bounded by lamina terminals which = at level rostral commissure and optic chiasma in adult brain, telencephalon vesicles expand rostrally covering and fusing with lamina terminals
- D aspect 3rd ventricle v bounded by rohofplate similar to 4th ventricle; choroid plexus develops in ependymal layer as blood vessels grow D to rohofplate
- V region 3rd ventricle = slit like and forms medial walls hypothalamus
what connects 3rd ventricle witth lateral ventricles
interventricular foramina
infundibular recess
small diverticulum 3rd ventricle extends into pituitary where it attaches to hypothalamus
mesencephalon components
tectum, mesencephalic aquaduct, mesencephali tegmentum (d -> V)
Telencephalon development
- synonymous with cerebrum/ cerebral hemispheres
1. Telecephalic vesicles expand laterally from wall pros encephalic vesicle at level lamina terminals
2. Expansion in all direction -> cerebral hemispheres covering diencephalon and mesencephalon and meeting each other D, Cd, and Rostral
3. Lumen NT within these vesicles will become lateral ventricles
4. Choroid plexus developes in single ependymal cell layer, this will be continuous with choroid plexus of 3rd ventricle
5. 2 populations of neurons form
6. cerebral cortex developes
chorioid plexus telencephalon
small region NT at medial aspect telencephalon doesn’t develop nervous tissue and remains angle layer of ependymal cells (like rohofplate); choroid plexus of each lateral ventricle develops with in this layer and will be continuous with choroid plexus of 3rd ventricle at interventricluar foramen
Development telencephalon leads to
2 populations of neurons, basal nuclei and cerebral cortex
basal nuclei
develop adjacent to ventricles= located v med deep to cortex
some basal nuclei include caudate nucleus, putamen, globes pallidus, amygdala, septal nuclei, nucleus accumbens
cerebral cortex development
developes from separate migration of neurons to surface of brain; neurons organized into layers (laminae) form sheets several mm thick -> cortex largely on surface of cerebral hemisphere with exception of hippocampal formation
3 regions cerebral cortex
paleocortex, archicortex, neocortex
paleocortex
appears early in evo hx; includes olfactory lobes, olfactory peduncles, piriform lobes
archicortex
appears early in evolutionary hx; includes hippocampal formation and fornix; gets pushed into deep position bc massive expansion of neocortex
neocortex
- developed in higher animals; covers much of paleocortex and archicortex in large domestic mammals
- 4 lobes frontal, parietal, temporal, occipital
- surface covered in sulci (grooves) and gyri (crests)
- to increase cortical processing must increase surface area while maintaining laminal architecture; expanded sheet folded into gyri like ribbon candy so brain fits into skull
internal capsule
white matter/ axons carrying info to neocortex from thalamus and from neocortex to brainstem
corona radiata
slips of white matter extending into individual gyri
corpus callosum
white matter/ axons connecting the L and R cerebral hemispheres
what separates the L and R hemispheres
fissure
Cerebellum
dorsal metencephalon
IV ventricle
trough on D surface of myselencephalon; v to cerebellum
medulla
mylencephalon
pon
v metencephalon
what connects 3rd and 4th ventricles
mesencephalic aquaduct
pyramids
2 longitudinal tracts on v surface myelencephalon on either side v midline, axons arise from UMN carry motor info to LMN for voluntary control of movement
cd aspect transverse fibers of pons
border of mylencephalon and metencephalon
trapezoid body
cd to transverse fibers fo pons at rostral aspect of v medulla
crus ceribri
on v aspect mesencephalon; made up of axons of UMNs carrying motor info from cerebral cortex to brainstem and spinal cord
folia
ridges in surface of cerebellum
4th ventricle location
btw pons and cerebellum; thin sheet tissue (rostral medullary vellum) = D aspect 4th V between cerebellum and mesencephalon
cerebellar cortex components
vermes (medial region)
hemisphere (lateral to vermes)
diencephalon rostral bounary
lamina terminalis at level of optic chiasma and rostral commusure
diencephalon cd boundary
apron line drawn between cd aspects of mammillary bodies (pt of thalamus) and pineal gland (pt of epithalamus);
diencephalon dorsal boundary
pineal gland caudally and roofplate of 3rd ventricle
what is on either side of 3rd ventricle
hypothalamus
what separates neocortex and paleocortex on v view of brain
fissure
cerebral hemispheres separated by
longitudinal fissure
cerebellum and cerebral hemispheres separated by
transverse fissure
lateral ventricle location
space cd and lateral to hippocampus and medial to caudate nucleus (a basal nucleus)
fornix
thin horizontal streak white matter D to 3rd ventricle and V to corpus callosum
Gyri
folds
sulci
depressions between fold
corpus callosum
thick horizontal streak white matter d to fornix
septum pellucidum
thin sheet tissue spanning gaps btwn corpus callous and fornix and separating lat ventricles
gastrulation
leads to trilamincr embryo (endoderm, mesoderm, ectoderm) and notochord (from mesoderm)
neurulation
creates neural tube will -> brain and spinal cord; end result is neural tube which is pseudo stratified neuro-epithelium that lines neural canal
neural plate
formed by thickening of ectoderm that overlies notocord
neural groove
formed by invagination fo neural plate
rhombencephalon
hind brain= fusion of tissues at junction of neural and non-neural ectoderm fuse starting here
neuropores
r and cd extent neural tube= last regions of tube to close
somites
mesenchymal cells derived from somites migrate D and V to neural tube btwn neural tube and overlying ectoderm -> meninges, skull, and vertebrea overlying CNS
calvaria
skull cap
vertebral arch
posterior pt of vertebrea
meninges
CT surrounding brain, spinal cord, these include Pia matter, arachnoid, and dura matter
myloschisis
cleft in spinal cord bc incomplete closure neural tube -> exposure neural tube -> spinal cord degeneration -> abnormal spinal cord development -> vertebral arches failing to form -> spina bifida
rachisys
spina bifida overlying large area
meningocele, meningomyelocele, menigoencephalocele
cyst like protrusion of meningess, meninges and spinal cord nervous tissue or meninges and brain tissue b/c deffect in vertebral column or calvaria
spina bifada
defective closure of vertebral arch
cranioschisis
defective closure of calvaria -> meninges, braincase, and skin can’t form b/c neural tube doesn’t close -> lumen of ventricle exposed in failure rostral neural tube closure -> cranioschisis; can be caused by menigiocele/ meningioencephalocele (protruding mass of brain/ meninges prevents normal calvaria formation)
schisis
cleft
myelo
spinal cord
cele
cyst
encephalo
brain tissue
cranio
skull
neural tube closure
begins at level of rhombencephalon, proceeds rostrally to idly, regions of neural tube changing shape to reflect brain regions they’ll develop into as regions in neural tube close
neural crest cells
migrate D -> V-lat; form segmental clusters cells D-lat to NT -> DRG
- 1 process grows to periphery w/ dendritic zone for sensory info from somatic or visceral tissues
- other processes grow centrally -> DR, synapse at DH
- proximal regions of central and peripheral processes fuse -> pseudo unipolar neuron
NCC migration
NCC may migrate -> contribution to PNS neurons in sensory and autonomic ganglia enter NS
germinal neuroepithelium
-> neurons, ependymal cells, and most of glial cells of CNS; remain adjacent to neural canal as development proceeds; increase in # leads to increased size neural tube and canal
where to ependymal cells come from
cells left from germinal neuroepithelium post development -> ependymal cells = will line ventricles and central canal= fluid filled spaces located w. in NT of CNS; some cells adjacent to ventricles can generate new neurons into late adulthood
germinal cells
differentiate into neuronal and glial cell precursors
grey matter
neurons and glial cells develop into this
D and V to neural canal, walls of neural tube
are thin, these cells -> choroid plexus, floor plate, roof plate
floorplate
germinal/ ependymal cells at ventral aspect of NT
roofplate
germinal/ ependymal cells at dorsal aspect of NT
sulcus limitans
longitudinal groove in lateral wall neural canal -> division grey matter of cd brain and spinal cord into D and V regions
alar plate
D to sulcus limitans; neurons involved in sensory processing
basal plate
V to sulcus limitans; many neurons in this region develop into LMN
VE neurons
formed by neurons at junction of alar and basal plates
white matter
developing neurons in grey matter send out axonal processes forming white matter; axons connect to CNS via rostral or cd projection; axons developing motor neurons may leave CNS forming VRs and CNs
central process from pseudounipolar neurons in DR and CN sensory ganglia ->
sensory neurons in DH -> contribution to white matter
ventricle
fluid filled spaces developed from neural canal and lined by ependymal cells in brain
central canal
fluid filled spaces developed from neural canal and lined by ependymal cells surrounded by spinal cord
choroid plexus
ventricular system and central canal of spina cord resulting from 5 brain divisions filled with CSF that is produced by choroid plexsus
forebrain
prosencephalon
midbrain
mesencephalon
hindbrain
rhombencephalon
Prosecencephalon -> vesicle -> ventricle
telencephalon -> lateral ventricle
diencephalon -> 3rd ventricle
mesencephalon -> vesicle -> ventricle
mesencephalon -> mesencephalic aquaduct
rhombencencephalon -> vesicle -> ventricle
metencephalon -> rostral 4th ventricle
Myelencephalon -> cd 4th ventricle
telencephalon components
neocortex, archiocortex, paleocortex, basal nuclei
diencephalon components
thalamus, hypothalamus, subthalamus, epithalamus
mesencephalon components
tectum, tegmentum, cerebral peduncles
metencephalon components
pons (v metencephalon), cerebellum
myelencephalon
medulla oblongotta
dorsal horn
somatic sensory and visceral sensory (afferent)
ventral horn
visceral motor and somatic motor (efferent)
VE
in intermediate grey along w/ interneurons
LH
in thoracic and lumbar regions (symp VE neurons) = in intermediate grey
forebrain fxs
forebrain= prosencephalon= telenephalon and diencephalon fxs: concious awareness learning decision making complex motor behavior
forebrain lesion manifestations
- deficits in concious perception (ex. nasal analgesia)
- behavioral abnromalities
- specific motor abnormalities (ie postural rxn deficits, complex gate manuvers)
- mention (dull change personality)
- seizures
- wide circling/ wandering/ drifting
forebrain lesions representation
contralateral
cd brainstem fx
midbrain, pons, medulla oblongata
- Fx of CNs III-X and XII b/c nuclei for these located here
- generation fo gate
- control of vital fxs (respiration, heart rate, blood pressure)
- controls arousal and consiousness
- motor and sensory pathways traveling btwn spinal cord and cerebrum like those involved in postural runs and conscious perception of stimuli must pass through
cd brainstem lesions representation
ipsilateral
cd brainstem lesions manifestations
- lack of consciousness/ unconciousness
- CN deficits (III-X and XII) ex. drooping ear, ptosis
- lack vital fxs
cerebellum representation
ipsilateral
cerebellum fx
90% matter in animals
- motor coordination, vestibular fx
cerebellar lesion manifestations
- generally NOT depressed or cognitively impaired NOT weak
- ataxia
- intention tremors (head approaches target and oscillates bc cerebellum plays role in motor skills)
- hypermetria (exaggerated movements)
- +/- vestibular dysfunction