Med Neuro Flashcards
What are 4 types of brain herniations?
- Subfalcine 2. Central 3. Transtentorial 4. Tonsillar
Which type of brain herniation syndrome has no symptoms?
Subfalcine - limbic lobe [emotion] is compressed (sagittal section of brain)
Which type of brain herniation syndrome can result in abducent nerve palsy?
Central - brainstem towards foramen magnum inferiorly - pressure on cranial nerves
What is compressed in a transtentorial herniation?
Medial temporal lobe - uncus [smelling]
Which type of brain herniation syndrome can affect respiratory centers?
Tonsillar - from increased pressure in cranial cavity
What are the only two places the arachnoid mater dips into the sulci and fissures of the brain?
- Falx 2. Tentorium
Where is the CSF located?
In the subarachnoid space
Where does the CSF return to the venous circulation?
Through the arachnoid villi
Arachnoid villi
Projections of arachnoid and subarachnoid space projecting into dural venous sinuses
Pia mater
- Follows contours of brain 2. Covers vessels of brain separates subarachnoid from perivascular space [Virchow-Robin space] 3. 2-3 cells thick; microscopic
What does the interventricular foramen of Monro connect?
The lateral ventricles to the 3rd ventricle
What is the role of the choroid plexus?
Secretes CSF
Septum pelucidum
Separate lateral ventricles
What 3 main functions does the frontal lobe have?
- Higher cognitive function - personality/judgements 2. Primary motor cortex - control of voluntary movements 3. Motor area for speech
What 2 main functions does the parietal lobe have?
- Conscious sensation - pain, pressure, touch 2. Association cortices (associate what sensation is coming from)
What 2 main functions does the temporal lobe have?
- Comprehension of language 2. 1˚ auditory cortex - hearing
Wernicke’s area is located where?
Superior temporal gyrus
What are the 2 main functions of the occipital lobe?
- Vision 2. Processing visual information - motion, edge, color
Where is the 1˚ visual cortex located
Occipital lobe along calcarine fissure - striate cortex - Brodmanns area 17
What are the 5 main functions of the Limbic Lobe?
- Fighting 2. Fleeing 3. Feeding 4. Feeling 5. Fucking
Uncus (Limbic)
Part of 1˚ olfactory cortex
Amygdala
Cluster of grey matter - emotions and memory
Insula
Homeostasis, motor control, emotions, self (deep to temporal lobe)
What are two types of basal ganglia (clusters of neural bodies)?
- Caudate nucleus 2. Lenticular nucleus
_____________ makes up the lateral wall of the lateral ventricle.
Caudate nucleus
What is the role of the basal ganglia?
Motor activity/motor control
What are the two parts of the lenticular nucleus?
- Putamen (L) 2. Globus pallidus (M)
The ________ makes up the lateral wall of the 3rd ventricle.
Thalamus
The ____________ transmits all sensation except _____________ to the cerebral cortex.
- Thalamus 2. Olfaction
Epithalamus
Pineal gland - sleep/wake cycle
Cerebellum
Fine tuning movement/motor control
Vermis
Midline structure of the cerbellum
Brainstem functions (4)
- Maintains homeostasis 2. Sensory 3. Motor 4. ANS innervation of head and neck
The cranial nerves emerge from the ______________.
Brainstem
The ______________ anastomose to form the basilar artery.
Vertebral arteries
What is the DIAPHRAGMA SELLAE?
part of dura mater that surrounds pituitary gland
What is the general venous flow from the SUPERIOR SAGITTAL SINUS?
superior sagittal sinus–>straight sinus–>transverse sinus–>sigmoid sinus (joins superior petrosal sinus)–>IJV
Will arachnoid mater bleed if you cut it?
No–it is avascular
What is in the subarachnoid space?
CSF and vasculature
What is the ATRIUM of the lateral ventricles?
where temporal and occipital horns meet
From what developmental structure are the VENTRICLES in the brain derived?
neural tube lumen
What is the CENTRAL CANAL of the spinal cord?
remaining lumen of the spinal cord at brainstem
What structures are associate with the FOURTH VENTRICLE of the brain?
- Lateral aperature (of Luschka); on on each side of the cerebellopontine angle 2. Medial aperture (of Magendie); in cerebellomedularis cisterna
What two structures define the space in which the FOURTH VENTRICLE lies?
superior/inferior medullary velum
How many types of horns do the LATERAL VENTRICLES have and what are they?
- frontal (anterior) horn 2. Temporal (inferior) horn 3. Occipital (posterior) horn
How is CSF moved throughout the spinal cord?
pulsations of ependymal cells with cilia
What is a CISTERN?
a large area of CSF in the spinal cord
What is the CORPUS CALLOSUM?
nerve fivers connecting cerebral hemispheres
A baby bumped his forehead. He bumped the _____ part of his head.
rostral
A child fell backward and hit his head on the lawn. The child hit the _____ part of his head.
caudal
Where does the rostral/caudal angle change occur?
at the midbrain
What is a SULCUS?
a groove on the surface of the brain
What is a FISSURE?
a deep furrow or cleft
What is a GYRUS?
a prominent, rounded elevation on the surface of the cerebrum, between sulci/fissures
What are BROADMANN’S AREAS?
a map of cell patterns in the cerebral cortex
Which lobes does the SAGITTAL FISSURE separate?
two halves of brain
Which lobes does the SYLVIAN (lateral) FISSURE separate?
temporal lobe from frontal/pariteal
Which lobes does the CENTRAL SULCUS (of Rolando) separate?
frontal and parietal loves
Which sulcus separates the occipital and parietal lobes? Where can it be seen
-PARIETOOCCIPITAL SULCUS -is only seen from a half-brain specimen
Where is the CALCARINE FISSUE located?
seen on a half-brain specimen; located in occipital lobe
What are dysphasias? What lobe is damaged if you have this problem?
-trouble speaking -in Brocha’s area [motor] in frontal lobe
How many gyri does the FRONTAL LOBE have and what are they?
- Precentral gyrus 2. Superior gyrus 3. Middle gyrus 4. Inferior gyrus 5. Gyrus rectus (seen in 1/2 brain specimen) 6. Orbital gyrus (seen in 1/2 brain specimen)
Which gyrus of the FRONTAL LOBE holds the primary motor cortex?
precentral gyrus
Which gyrus of the FRONTAL LOBE holds BROCA’S AREA?
left hemisphere of the inferior gyrus
Which lobe of the brain have you injured if when you close your eyes, you cannot recognize that your left hand is yours?
PARIETAL LOBE
Which gyrus of which lobe did you injure if you cannot comprehend language (aphasia)?
supramarginal gyrus of the parietal lobe
Where is the primary AUDITORY CORTEX located?
superior temporal gyrus
What are the functions of the TEMPORAL LOBE of the brain?
- Hearing 2. Comprehension of language
Which part of the brain is associated with comprehending sounds?
Wernicke’s area of the superior temporal gyrus
What are the functions of the OCCIPITAL LOBE of the brain?
- vision 2. interpretation of visual images
What is it called when you are an epilepsy patient and you smell something bad before a seizure? Where is the seizure affecting in the brain?
-UNCINATE FIT -UNCUS
The hypothalamus has _____ and ______ functions.
-endocrine -ANS
What are MAMILLARY BODIES?
part of limbic system (memory)
What can cause CEREBELLAR TONSILS to herniate through the foramen magnum?
hemorrhage
In the SPINAL CORD, _______ matter is on the inside and ______ matter is on the outside.
-gray (cell bodies) -white
What are the 4 types of brain herniations?
- Subfalcine 2. Central 3. transtentorial 4. tonsillar
What is a SUBFALCINE herniation and what does it affect?
when the cingulate gyrus goes under the falx cerebri; affects the limbic lobe (emotion)
What is a CENTRAL herniation and what does it affect?
when brainstem goes toward the foramen magnum; can cause CN VI palsy–>superior oblique muscle paralysis (eye can’t move down and in)
What is a TRANSTENTORIAL herniation and what does it affect?
when medial temporal lobe (UNCAL area) goes through the tentorial notch; can lose sense of smell
What is a TONSILLAR herniation and what does it affect?
when cerebellar tonsils go through foramen magnum; can cause problems with respiration and other basic functions (of brainstem)
Where is the vasculature that supplies blood to the brain?
in the subarachnoid space
Arachnoid villi return ______ to ______.
-CSF -Venous circulation/sinuses
Where are the only places where the ARACHNOID MATER folds onto itself?
arachnoid trabeculae
PIA MATER separates the ________ from the ________.
-subarachnoid space -perivascular space
What is a VIRCHOW-ROBIN SPACE?
pia mater; covers blood vessels in subarachnoid space where blood vessels go into perivascular space
Name the 3 horns of the LATERAL VENTRICLES.
- anterior/frontal 2. inferior/temporal 3.posterior/occipital
What is the name of the place where the temporal and occipital horns of the LATERAL VENTRICLE meets?
ANTRUM
What is the structure that allows CSF to flow from the 3rd to 4th ventricle?
cerebral aqueduct (of Sylvius)
There are two _______ of the fourth ventricle and one _____ of the fourth ventricle that drain CSF into the spinal cord.
-lateral apertures (foramina of Luschka) -medial aperture (foramen of Magendie)
What is the CENTRAL CANAL of the spinal cord?
remaining lumen of spinal cord
The ventricles were derived from the __________ in embryonic development.
neural tube lumen
Where is the CHOROID PLEXUS located?
in lateral and 3rd ventricles (only a little in 4th in lateral foramen of Luschka)
What is the SEPTUM PALLUCIDUM?
thin, lucid tissue that separates the 3rd ventricles on either side
The _______ connects the cerebral hemispheres.
corpus callosum
What is a cistern?
a large area filled with CSF in spinal fluid
______ moves CSF by pulsations in the SC.
ependymal cells
The change in _________ occurs at the midbrain.
rostral/caudal angle
Which structures make up the LIMBIC LOBE?
- amygdala =emotion; gray matter (more anteriorly) 2. hippocampus = memory (more posteriorly) [both on either side of brainstem, posteriolateral to 3rd ventricle] 3. Uncus (smell) 4. Parahippocampal gyrus 5. cingulate gyrus/sulcus
What is the INSULA and where is it located?
deep part of lateral sulcus; not technically part of any lobes; for olfaction, indiscriminate touch (self-awareness)
The ______ always makes up the lateral walls of the anterior horn of the lateral ventricles.
Caudate nucleus
What does the BASAL GANGLIA consist of? What is its function?
- caudate nucleus 2. lenticular nuclei (putamen, globus pallidus) -precise control of VOLUNTARY MOTOR movement
What makes up the BASAL GANGLIA?
gray matter = neural cell bodies [deep within white matter]
What two areas make up the LENTICULAR NUCLEI?
- putamen (vertical upon coronal section) 2. globus pallidus (horizontal upon coronal section)
The _____ makes up the lateral wall of the 3rd ventricle.
THALAMUS
What is the main function of the THALAMUS?
transmits ALL SENSATION (except olfaction) to cerebral cortex for processing
Do the olfactory bulb neurons pass through the thalamus?
NO!
Which brain region has both endocrine and ANS functions?
HYPOTHALAMUS
The ____________ in the ________ region of the brain is sensitive to light and plays a role in the sleep/wake cycle.
-pineal gland -epithalamus
What is the DIENCEPHALON and what 5 regions are in it?
- region of the embryonic vertebrate neural tube that gives rise to posterior forebrain structures 1. thalamus 2. hypothalamus 3. epithalamus 4. subthalamus 5. mamillary bodies
Which part of the diencephalon deals with memory disturbances?
mamillary bodies
MAMILLARY BODIES are part of the _______.
limbic system
The _________ processes sensory information to regulate smooth movement.
CEREBELLUM
Where is the VERMIS on the cerebellum?
in the midline
What are the two bumps lateral to the vermis called? And what can happen to them due to trauma?
-cerebellar tonsils -herniation through the foramen magnum
What 3 structures does the brainstem consist of?
- midbrain 2. pons 3. medulla
What is the function of the BRAINSTEM?
- homeostasis 2. sensory, motor and ANS innervation of the neck/head (chemoreceptors, pressure receptors, etc.) 3. special senses
Which two structures does the MIDBRAIN consist of? And where are they located?
- Tectum (superior/inferior colliculi); posterior to cerebral aqueduct 2. Tegmentum (cerebral peduncles); between cerebral aqueduct [post] and basal pons [anterior]
What are the 4 parts of the SPINAL CORD?
- cervical 2. thoracic 3.lumbar 4. sacral
What does the inner, H-shaped area of the spinal cord consist of?
gray matter = cell bodies
What does the outer, non-H-shaped area of the spinal cord consist of?
white matter = axons
Which physical structures make up the OCCIPITAL LOBE?
- Preoccipital notch 2. Calcarine fissure 3. Striate cortex 4. Cuneus 5. Lingual gyrus
Which 3 symptoms can tip off a doctor that a patient is having a stroke?
- sudden onset 2. focal, neurologica symptoms = unilateral 3. cerebrovascular cause is a possible explanation
About _____ are ischemic strokes and _______ are hemorrhagic strokes.
-85% -15%
What causes an ISCHEMIC stroke?
blockage in vasculature of brain becomes blocked and then area becomes infarct
What causes a HEMORRHAGIC stroke?
a vessel in the vasculature of the brain ruptures
Does altered consciousness usually indicate a stroke?
NO! not usually, because usually a neurological, unilateral problem
What are some specific symptoms that indicate a patient could be having a stroke?
- hemi-field cut/ monocular blindness 2. aphasia/can’t understand speech (nonsense words) 3. weakness of one side of face 4. numbness on one side
What could cause a hemi-field cut or monocular blindness?
A carotid plaque could block flow to the optic nerve and retina and therefore deplete blood to that area of sight on one side
What is the difference between hemi-field cut and monocular blindness?
-hemi-field = vision loss in both eyes at optic chiasm; can be caused by ACA -monocular blindness = vision loss in one of two optic nerves before it enters optic chiasm
What are the two types of ISCHEMIC STROKES?
- thrombotic (athlerosclerosis; irregularities of surface cause clotting–many clots at bifurcation causes turbulent flow) 2. embolic (traveling particle, like from atrial fibrillation)
What are the 2 types of HEMORRHAGIC STROKES?
- intracerebral (in parenchyma caused by hypertension) 2. subarachnoid (aneurysm due to defect in vessel; can be congenital or trauma)
Which type of HEMORRHAGIC STROKE is the most lethal?
subarachnoid
What does a subarachnoid hemorrhage look like on CAT scan?
blood fills ventricles
What does a intracerebral hemorrhage look like on CAT scan?
only within brain parenchyma; midline shift = squished ventricles
What are the 3 main arterial branches that we can diagnose as causes for ischemic stroke?
- anterior cerebral artery (midline) 2. middle cerebral artery (lat) 3. posterior cerebral artery (midline)
What is ISCHEMIC PENUMBRA?
parenchyma proximal to ischemic area that can be salvaged (time permitting) due to collateral flow and autoregulation (dilation) of nearby blood vessels
CNS axons are myelinated by _______________, while PSN axons are myelinated by ________________.
- Oligodendrocytes 2. Schwann cells
What are the 5 types of glial cells?
- Astrocytes 2. Oligodendrocytes 3. Schwann Cells 4. Microglia 5. Ependymal Cells
What are the two types of astrocytes? Where are they located?
- Fibrous in white matter 2. Protoplasmic in gray matter
One oligodendrocyte can myelinate _________________.
Many CNS axons
One Schwann cell can myelinate _____________________.
One segment of a PNS axon
What causes gliosis?
Proliferation of astrocytes after neuronal damage
What are the functions of astrocytes? (7)
- Structural support and repair (GFAP)
- K+ spatial buffering
- NT and metabolite removal - GLAST
- Contribute to BBB
- Communicate w/ each other via gap junctions
- Glial guide for neuronal migration
- Subset serve as stem cells to generate neurons and glia
Are astrocytes electrically excitable?
No
___________ is a potent inhibitor of axon outgrowth and regeneration.
Central myelin
What are 3 inhibitors of CNS axonal elongation?
- Myelin-associated glycoprotein (MAG) 2. Neurite inhibitor of 35 kDa (NI-35) 3. Nogo gene and proteins NI-220/250
A single axon in the PNS can by myelinated by ___________ Schwann cell.
50-500
Schwann cells provide what 3 types of growth promoting factors? (3)
- Laminin (SC basal lamina)
- Cell adhesion molecules: NgCAM/L1
- Some secrete nerve growth factor
What is the function of microglia?
Function as macrophages - phagocytose debris of CNS
When neurons undergo degeneration microglia increase in ____________________.
Size and number
What are 3 functions of ependymal cells?
- Provide a barrier between brain and CSF 2. Aid in CSF circulation 3. In choroid plexus produce CSF
Where are ependymal cells found?
Lining inside of neural tube - cerebral ventricle and cerebral canal
The outer mesaxon is only present in the _____.
PNS (because the Schwann cell wraps around itself)
Myelin has a high ______ content
Lipid
MBP
Myelin basic protein
- major structural protein of myelin in CNS (also present in PNS)
- basis for autoimmune disease (encephalomyelitis)
- on cytoplasmic face of myeilin membrane (MAJOR dense line)
What is MAG? What is its function?
Myelin-associated glycoprotein - in oligodendrocytes in CNS and PNS; inhibits the initiation of myelination
MOG
Myelin-oligodendrocyte glycoprotein - CNS only - on surface of myelin sheath
_____ is a target antigen in autoimmune aspects of CNS demyelinating disease.
MOG
Nodes of Ranvier have a high concentration of _________________.
Voltage gated Na+ channels
Nodes in the CNS are ___________ and nodes in the PNS are _________.
- Bare 2. Covered by Schwann cell cytoplasm
What is the function of clefts (incisures)
Delivery of cytoplasmic nutrients to inner leaflets of myelin
Schmidt-Lanterman incisures (clefts) are found in the _____. What is their function?
- PNS
- to supply cytoplasmic nutrients to the inner leaflets of myelinated axons
Longitudinal incisures are found in the _____. What is thier function?
- CNS
- to provide nutrients to inner leaflets
What is the peak conduction velocity in myelinated axons?
120 m/s
What is the conduction velocity in unmyelinated axons?
<2 m/sec
Multiple Sclerosis
Chronic demyelinating disease of CNS (antibodies against own myelin) - results in gliosis, slowed conduction, disruption of BBB, paralysis, sensory-motor deficits
Guillain-Barré Syndrome
Acute, autoimmune, inflammatory demyelinating disease of PNS (muscles/skin) - slowed/abnormal conduction results in sensory perception and motor coordination issues
What famous person is thought to have had Guillain-Barré syndrome? Why?
- FDR
- because the symptoms resembled the characteristic GB symptoms: moved from legs upward; also, FDR was documented to have fever before his paralysis
Membrane lipid-bilayer is a diffusion barrier functioning as a ________.
Capacitor
The _______ and _____ are long arteries branch off the internal carotid artery in the base of the brain.
-MCA -ACA
What are the 2 long branches from the ACA?
- Cortical branches to the medial aspect of the frontal/parietal lobes 2. arteries to corpus callosum (callosalmarginal and pericallosal a.)
What are the 2 long branches from the ACA?
- Cortical branches to the medial aspect of the frontal/parietal lobes 2. arteries to corpus callosum
What long branches does the MCA branch into?
cortical (superior) branches to frontal, parietal and temporal lobes
What short branches come off the MCA? What do they supply?
-lenticulostriate arteries -basal ganglia, internal capsule
What short branches come off the MCA?
lenticulostriate arteries
What 2 long branches come off the vertebral arteries?
- PICA (posterior inferior cerebellar a) 2. posterior spinal aa.
What short branches come off the vertebral arteries?
anterior spinal aa
What 4 branches come off the BASILAR artery?
- superior cerebella a. 2. long pontine arteries 3. short pontine arteries 4. anterior inferior cerebellar a. (AICA)
What 2 short branches come off the PCA?
- posterior choroidal a. 2. arteries to thalamus
What 2 short branches come off the PCA?
- posterior choroidal a. 2. arteries to thalamus
What does ACA supply?
anterior, medial as far back as sensorimotor cortex [leg/foot]; cingulate and superior frontal gyri, frontal lobes, paracentral lobules, corpus callosum frontal pole; anterior limb of internal capsule (medial striate artery)
A patient cannot move his leg or foot on his right side. Where could there be a thrombosis?
on left ACA (sensorimotor cortex)
From which artery does the anterior choroidal come? What does it supply?
-ICA - midbrain, basal ganglia, internal capsule, parts of visual pathway
The ______ artery passes through the Sylvian fissure in the temporal lobe.
MCA
What does a lesion in the RIGHT SUPERIOR hemisphere of the MCA of the brain cause?
weakness and/or sensory loss of left FACE, HAND, ARM, TRUNK
What does a lesion in the LEFT SUPERIOR hemisphere of the MCA of the brain cause?
weakness and/or sensory loss of right FACE, HAND, ARM, TRUNK and BROCA’S AREA = APHASIA (cannot move , but can understand)
What does a lesion in the LEFT INFERIOR hemisphere of the MCA of the brain cause?
sensory loss from right face, hand, arm, WERNICKE’S AREA = aphasia (cannot understand but can move); posterior part of superior temporal gyrus
What does a lesion in the RIGHT INFERIOR hemisphere of the MCA of the brain cause?
sensory loss from left face, hand and arm; left hemineglect (proprioception; draw only half a picture)
What is paraphasia?
speech is incomprehensibe
Branches of the _____ causes visual field defects when occluded.
MCA
When the __________ arteries are occluded (they supply blood to the ________), the patient experiences contralateral perisis or paralysis.
-lenticulostriate -internal capsule
The vertebral arteries branch from the _________ artery and pass through the _____ of the cervical vertebrae and enter the cranial cavity through the ______.
subclavian transverse foramina foramen magnum
The ANTERIOR SPINAL ARTERIES, branching off the ____ arteries, supply the ________ of the spinal cord and the _______ medulla.
-vertebral -anterior 2/3 -anterior/medial medulla {including medullary pyramids}
The POSTERIOR SPINAL ARTERIES, branching off the _______ arteries, supply the ________ of the spinal cord and the _______ medulla.
-vertebral -posterior 1/3 -posterior part of medulla
From where do the PCAs come from?
basilar artery
The ANTERIOR INFERIOR CEREBELLAR ARTERIES, branching off the ____ artery, supply the ________ of the cerebellum and the _______ of caudal pons.
-basilar -anterior portions of interior -lateral part
The SUPERIOR CEREBELLAR ARTERIES, branching off the ____ artery, supply the ________ of the cerebellum, the _______ of middle pons and the _____.
-basilar -superior part -lateral part -pineal gland
The ______ arteries, branching off the _____ artery, supply the inner ear.
-labyrinthine -basilar
What deep cortical structure does the PCA supply? The _______ and ________ arteries also supply this structure.
-thalamus -basilar -posterior communicating
What deep cortical structure does the PCA supply? The _______ and ________ arteries also supply this structure.
-thalamus -basilar -posterior communicating
__________ of the brain form a barrier (BBB) between the circulation and the interstitial fluid.
endothelial cells lining the microvasculature
What is the function of the BBB?
maintains stable microenvironment for proper functioning of neurons within CNS
General capillaries have ______ and _____ while brain capillaries have ______ and _____ to provide a physical barrier.
-fenestrae/gaps between adjacent endothelial cells -pinocytotic vesicles -tight junctions (est. polarity) -few pinocytotic vesicles
Most molecular traffic must take a _________ route if it is going to cross the BBB.
intracellular (pinocytosis)
Endothelial cells in BBB surrounded by what 3 structures?
- basal lamina 2. pericytes (smooth muscle-like) 3. astrocyte foot processes (cover abluminal surface)
What is the abluminal surface?
side that faces toward the brain, away from EC
_______ provide the cellular link to neurons.
Astrocytes
What are 5 ways substances can pass between BBB?
- paracellular aqueous (water soluble) through tight junctions 2. transcellular lipophillic (O2, ethanol, CO2, etc.)**** 3. transport proteins (glucose, amino acids, AZT, etc.); lumenal/ablumenal surfaces 4. receptor-mediated transcytosis (insulin, transferrin 5. adsorptive trancytosis
What is the route by which most neurological drugs enter the brain?
trancellular lipophilic pathways