Neuroanatomy Flashcards
Anterior Circulation: from __________ artery → entire cerebral hemisphere except medial occipital lobe and inferior part of temporal lobe
internal carotid artery
internal carotid artery give of what two arteries?
Anterior cerebral a.
Middle cerebral a.
________ cerebral a. → longitudinal fissure to supply anterior ⅔ of medial face of cerebral hemisphere and orbital cortex
Anterior cerebral a.
________ cerebral artery →lateral fissure to supply lateral face of cerebrum (frontal, parietal, and temporal lobes)
Middle cerebral a.
Gives off penetrating branches to supply deep white and gray matter of cerebral cortex
Posterior Circulation in the brain comes from what arteries?
vertebral arteries
Posterior Circulation supplies what brain regions?
brainstem, cerebellum, some cortex (medial occipital, inferior temporal lobe)
At level of pons, vertebral arteries fuse to form _______ artery
basilar artery
At level of (what brain region) , vertebral arteries fuse to form basilar artery
pons
basilar artery → splits at base of midbrain to form paired _____________ arteries
posterior cerebral arteries
paired posterior cerebral arteries → (supplies)
medial face of occipital lobe and inferior surface of temporal lobe.
Along course of vertebral/basilar system, circumferential branches wrap around brainstem → dorsal brainstem and overlaying cerebellum. What are the name of these 3 arteries?
Posterior Inferior Cerebellar Artery (PICA)
Anterior Inferior Cerebellar Artery (AICA)
Superior Cerebellar Artery (SCA)
___________ Cerebellar Artery : branch off vertebral artery, wraps medulla and supplies most caudal cerebellum
Posterior Inferior Cerebellar Artery (PICA)
Posterior Inferior Cerebellar Artery (PICA): branch off vertebral artery, wraps ________ and supplies most caudal cerebellum
medulla
Posterior Inferior Cerebellar Artery (PICA): branch off vertebral artery, wraps medulla and supplies most of the _________
caudal cerebellum
___________ Cerebellar Artery: branch off basilar artery, wraps caudal pons, supplies anterior/inferior cerebellum
Anterior Inferior Cerebellar Artery (AICA)
Anterior Inferior Cerebellar Artery (AICA): branch off basilar artery, wraps around the _________, supplies anterior/inferior cerebellum
caudal pons
Anterior Inferior Cerebellar Artery (AICA): branch off basilar artery, wraps caudal pons, supplies the __________
anterior/inferior cerebellum
Of the PICA, AICA, and SCA, which one branches from the basilar a.?
AICA
SCA
Of the PICA, AICA, and SCA, which one branches from the vertebral a.?
PICA
The entire blood flow to CNS can be supplied via any of which 3 major vessels?
L Carotid, R Carotid, or Basilar artery
What arterial vessel system connects anterior and posterior circulation systems at base of brain?
Circle of Willis
CSF gets reabsorbed through _______ space
subarachnoid
What structure connects lateral ventricles with 3rd ventricle (one for each lateral ventricle)
Interventricular foramen
What structure connects 3rd and 4th ventricles?
Cerebral aqueduct
______ apertures connect 4th ventricle with subarachnoid space.
Three apertures (two lateral, one caudal) connect 4th ventricle with subarachnoid space.
Ependyma: ?
Ependyma: single cell layer lining ventricles
Leaky → CSF in ventricles exchanges freely with ECF in interstitial space in brain
What are the specialized ependymal cells that produce CSF?
Choroid Plexus:
How much CFS is produced by the choroid plexus everyday?
500ml.
only 125ml of CSF in NS at any time
Resorption of CSF is done by the ______________ that line principal dural sinuses
arachnoid granulations
____________ Hydrocephalus: flow of CSF interrupted (e.g. by block of interventricular foramen of cerebral aqueduct)
Non-Communicating Hydrocephalus
__________ Hydrocephalus: CSF gets into subarachnoid space, but isn’t resorbed properly into the bloodstream
Communicating Hydrocephalus
The Meninges:
___?___: single cell layer covering outside of CNS, not separable from brain surface.
Pia
The Meninges:
___?___: loose spongy layer between pia and dura
Subarachnoid space filled with CSF.
Arachnoid
The Meninges:
____?____: leathery layer closely applied to cranium, but loose on spinal column.
Dura
Local increase in neuronal activity → increase in local blood flow. This is known as what?
Functional Hyperemia
Functional Hyperemia is the basis what which clinical tool?
basis for fMRI and PET scans)
Type of imaging of the brain:
___1___ uses intrinsic properties of Hgb to measure blood flow.
___2___ scans uses injected tracer
- fMRI
2. PET
What are the two mechanisms of Functional Hyperemia?
1) NO released by neurons diffuses to reach local vessels to cause dilation
2) Astrocytes (see below)
Why substances in circulatory system do not freely enter brain parenchyma?
Capillaries in brain are NOT fenestrated, connected by tight junctions → requires diffusion or transport through endothelial cell
BBB maintained by astrocytes - tell endothelial cells to maintain tight junctions
How do Astrocyte regulation of local blood flow in proportion to neuronal activity?
Astrocyte “foot processes” extend towards local blood vessels, contact vessel walls → carry nutrients and oxygen from vessels to neurons and regulates vessel function.
Increased neuronal activity → increased astrocytes uptake of glutamate (most prevalent NT) → causes release of arachidonic acid in astrocytes → arachidonic acid converted by P450 enzyme to form epoxyeicosatrienoic acid (EET) → astrocyte EET released and acts to hyperpolarize arteriole membrane → decrease vascular tone → larger lumen → increased blood flow.
Describe what neural cells are regenerated during MINOR damage in the PNS?
distal portion of nerve ending degenerates, but regeneration begins from end still attached to cell body
Regeneration of axons along course of original nerve, facilitated by Schwann cells
Schwann cells clear myelin debris, then line endoneurium to form substrate for outgrowth of axons from cut stump of nerve
What are the long term effects of MINOR damage in the PNS?
alterations in sensory perception in affected area (hypersensitivity, hyperalgesia, allodynia)
Response of local microglia upregulate cytokines and trophic factors, and reorganization of synapses→ activate astrocytes
In the PNS, _______ clear myelin debris, then line endoneurium to form substrate for outgrowth of axons from cut stump of nerve
Schwann cells
After damage, what do Oligodendrocytes during regeneration in the CNS?
Oligodendrocytes do not clear myelin debris - proliferate and upregulate expression of molecules (chondrotin, sulfate proteoglycans) that inhibit axonal outgrowth
Axons do not regrow!
After damage, what do Microglia during regeneration in the CNS?
Microglia activate local astrocytes to form glial scar → chemical and physical barrier to neuronal regeneration
Microglia activate local __(what cell type____ to form glial scar → chemical and physical barrier to neuronal regeneration
Microglia activate local astrocytes to form glial scar → chemical and physical barrier to neuronal regeneration
Where do microglia arise from embryologically?
Arise embryologically outside neural tube, from hematopoietic tissues
Do astrocytes help to maintain the BBB?
YES
Describe how astrocytes maintain ionic equilibrium of neural cells by taking up K+ and neurotransmitter?
Glutamate (convert glutamate to glutamine → glutamine back to local neurons → neurons convert glutamine back to glutamate)
Precentral Gyrus = _____ cortex
motor cortex
Postcentral Gyrus = ______ cortex
somatosensory cortex
Anterior Cerebral Artery
Supplies most medial portions of frontal lobes and superior medial parietal lobes
Anterior Communicating Artery
Connects the anterior cerebral arteries at their closest juncture
Internal Carotid Artery
Ascends through base of skull to give rise to the anterior and middle cerebral arteries, and connect with posterior half of circle of Willis via posterior communicating artery
Middle Cerebral Artery
Trifurcates into temporal, frontal, and parietal branches that supply most of the parenchyma of these lobes
Posterior Communicating Artery
Connects the anterior circle of Willis with the posterior cerebral artery of vertebral-basilar circulation posteriorly
Posterior Cerebral Artery
Supplies the occipital lobe and the inferior portion of temporal lobe. A branch supplies the choroid plexus.
Superior Cerebellar Artery
Supplies the dorsal cerebellum, pons, and midbrain
Basilar Artery
Formed by the junction of the two vertebral arteries, it terminates as a bifurcation into the posterior cerebral arteries
Anterior Inferior Cerebellar Artery
Supplies the inferior cerebellum and portions of pons and medulla
Vertebral Artery
The vertebrals emerge from the posterior base of skull and merge to form the basilar artery
Posterior Inferior Cerebellar Artery
Supplies the inferior-posterior cerebellum, choroid plexus in 4th ventricle, and portions of medulla
Anterior Spinal Artery
Descends along the anterior (ventral) aspect of the spinal cord
_________ matter is comprised of myelinated structures (axons) that have a high lipid content.
White matter
The glial environment in the _____ (CNS or PNS) prevents axonal regeneration.
The glial environment in the _____ (CNS or PNS) does NOT prevent axonal regeneration.
CNS
PNS
________ and peripheral neurons originate from the neural crest cells.
Schwann Cells
Microglia originate from which embryological germ later?
mesoderm
CNS Neurons, ependymal cells, oligodendrocyte and astrocytes originate from the ?
NeuroECTOderm
The _______ is the sensory relay point within the brain.
thalamus
________ is the conversion of a normally innoculus stimulus to a painful sensation. It usually occurs after damage to peripheral neurons that is followed by abnormal regeneration.
Allodynia
________ = the location at which neuronal tracts cross the midline forming an X
Decussation
________ = picture of human projected onto a brain.
Humunculus
________ = neurons that cross the midline and DO NOT make an X
Commisure
_________ = topographic relationship of brain with body
Somatotopy
What continually reabsorb CSF, and can send hormonal signals back into the blood stream.
Dural Sinuses
CSF is made in the _________ and flows unidirectionally through the brain until it reaches the hindbrain -> subarachnoid space -> veins.
choroid plexus
Of the 500mL of CSF made by the choroid plexus each day, only about ___ mL exists in the CNS at a given time due to constant re-absorption of CSF by the dural sinuses.
125mL
CSF is made in the ___1___ ventricles and drains into the ___2___ ventricle before being reabsorbed into veins. CSF flow through the brain is thus unidirectional.
- LATERAL
2. THIRD
The ______ Cerebral Artery supplies the somatomotor regions of the face/hands/feet on the side contralateral to the presenting symptoms.
Middle Cerebral Artery
The ______ cerebral artery supplies the inferior aspect of the temporal lobe and the medial aspect of the occipital lobe.
posterior cerebral artery (PCA)
Conduction velocity _________ as:
1) the diameter increases
2) higher density of sodium channels
3) increased membrane thickness (making the mebrane less “leaky” to ions)
increases
What embryological region is the secondary site for olfactory bulb cells.
Sub-ventricular zone
What embryological region is the secondary site for cerebellar cells?
External Granular Layer
Dentate gyrus is the secondary site for ________ cell
hippocampal
Cells in ?-phase are going to be located most superficially (closest to the pia) in the VZ.
S phase
What is the hotspots of neurogenesis after birth?
the secondary Zones
Lumen of the diencephalon = ____ ventricle
third ventricle
The alar plate will become the ________ parts of spinal cord and get input from corresponding dermatomes.
sensory (dorsal)
_____ plate = motor, and will send info to its corresponding myotome
Basal
Telencephalon = cerebrum and lateral ventricles (choroid plexus)
Diencephalon = thalamus, hypothalamus, 3rd ventricles
Mesencephalon = midbrain, cerebral aqueduct
Metancephalon = pons, cerebellum, part of 4th ventricle
Myelencephalon = Medulla, part of 4th ventricle
Telencephalon = cerebrum and lateral ventricles (choroid plexus)
Diencephalon = thalamus, hypothalamus, 3rd ventricles
Mesencephalon = midbrain, cerebral aqueduct
Metancephalon = pons, cerebellum, part of 4th ventricle
Myelencephalon = Medulla, part of 4th ventricle
_______ –> Medulla
Myelencephalon
What neural cells is injured in MS, progressive leukoencephalopathy (PML), and leukodytropies?
Oligodendrocytes
Issues with ACA (artery) shows what Sx?
contralateral paralysis and sensory loss–lower limb
Issues with MCA (artery) shows what Sx?
Contralateral paralysis and sensory loss–face and UPPER LIMB
_____ column (spinal column) = pressure, vibration, touch, proprioception.
DORSAL
_________ tract (spinal) = pain and temperature
Lateral Spinothalamic tract (anteriolateral [AL])