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140 Cards in this Set
- Front
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Chap 2
Describe the three layers of meninges: |
p21
The meninges are composed of three connective tissue membranes that surround the spinal cord and brain. 1. pia mater: delicate, highly vascular layer. It closely covers the surface of brain and spinal cord. 2. arachnoid: delicate, nonvascular. Between pia and dura. 3. Dura mater: outer layer, very dense. |
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Chap 2
What are the three meningial spaces? |
1. subarachnoid space: between pia and arachnoid. Contains the CSF. Ends at second sacral level.
2. Subdural space: in the crainium it is crossed by bridging veins (not significant in spine) 3. Epidural space: cranial epidural space contains meningeal arteries and veins; spinal epidural space contains fatty areolar tissue, lymphatics, and venous plexuses. |
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Chap 2
Where is local anesthetic injected to produce a paraverterbral "saddle" nerve block? |
Spinal epidural space
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Chap 2
What is a meningioma? |
FA p.362/HY p.21
Meningioma: second most common primary brain tumor. It is benign, well-circumscribed, and slow growing. More common in women 90% are supratentorial Found in convexities of hemispheres and parasagittal region Arises from arachnoid cells external to brain Resectable Appearance: Spindle cells concentrically arranged in a whorled pattern: psammoma bodies (laminated calcifications) |
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Chap 2
What is a subdural hematoma? |
FA p.362/HY p.21
Subdural hematoma: is caused by laceration of the superior cerebral (bridging) veins. Venous bleeding (less pressure) with delayed onset of symptoms. Seen in elderly individuals, alcoholics, blunt trauma, shaken baby Predisposing factors: brain atrophy, shaking, whiplash. |
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Chap 2
What is a epidural hematoma? |
FA p.362/HY p.21
Epidural hematoma: laceration of middle meningeal artery, often secondary to fracture of temporal bone. Lucid interval (see color image 44) CT shows "biconvex disk" not crossing suture lines. |
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Chap 2
Describe cytomegalovirus induced encephalitis: |
RR p.578
Cytomegalovirus: Most common viral CNS infection in AIDS Most common congential infection in kids Primary intranuclear basophilic inclusions Periventricular calcifications in newborns. |
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Chap 2
What body fluid is best used to diagnose congenital cytomegalovirus? |
RR p.578
Urine |
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Chap 2
Describe rabies virus encephalitis? |
RR p.578
Rabies: most often transmitted by skunk Virus ascends peripheral nerve Neurons contain intracytoplasmic Negri bodies CNS excitability stage followed by flaccid paralysis. |
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Chap 2
What is Creutzfeldt-Jakob disease? VIP! |
RR p.579
Unconventionally slow virus encephalitis due to prions (proteinaceous material devoid of RNA or DNA) Transmitted through corneal transplantation or contact with brain tissue, or ingestion of meat infected with bovine spongiform encephalopathy Brain has "bubble and holes" spongiform change in cerebral cortex. Death usually occurs within 1 year. |
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Chap 2
What is the most common cause of neonatal meningitis? |
RR p.579
Group B streptococcus, Strep Agalactiae Gram positive coccus Spreads from a focus of infection in maternal vagina |
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Chap 2
What is the second most common cause of neonatal meningitis? |
RR p.579
E. Coli: gram (-) rod |
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Chap 2
What is the most common cause of meningitis in those between 1 mth and 18 yrs? |
RR p.579
Neisseria Meningitidis |
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Chap 2
Why shouldn't pregnant women eat soft cheeses? |
RR p.579
Soft cheese has listeria monocytogenes which is the third leading cause of neonatal meningitis |
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Chap 2
Describe Listeria monocytogenes, an organism that can induce neonatal meningitis: |
Listeria is a gram positive rod with tumbling motility (like trichomonas)
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Chap 2
What is the most common cause of meningitis in someone > 18 yo? Describe organism? |
RR p.579
Strept pneumoniae Gram + diplococcus |
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Chap 2:
Goljan Q: 50yo main with meningitis most likely has: a. gram + coccus b. gram - rod c. gram + rod d. gram + diplococci |
D: Strept pneumoniae is a gram + diplococci
gram + coccus: group B strept agalactiae gram - rod: e. coli gram + rod: listeria |
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Chap 2
CSF findings in bacterial meningitis? (3) |
Bacterial meningitis
1. many PMM leukocytes 2. decreaed glucose 3. increased protein |
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Chap 2
CSF findings in viral meningitis? (3) |
Viral meningitis
1. many lymphocytes 2. normal glucose 3. increaed protein |
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Chap 2
What is the choriod plexus? |
Choroid plexus is a specialized structure that projects into the ventricles.
It is made of blood vessels from the pia mater that are covered in ependymal cells that secrete CSF. |
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Chap 2
What forms the blood-CSF barrier? |
Tight junctions of the choroid plexus cells form the blood-CSF barrier.
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Chap 2
How do the two lateral ventricles communicate? |
Through the third ventricle via the foramina of Monro
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Chap 2
How does the third ventricle communicate with the fourth? |
Via the cerebral aqueduct
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Chap 2
How does the fourth ventricle communicate with the subarachnoid space? |
Via two foramen called lateral foramina of Luschka
and One medial foramen of Magendie |
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Chap 2
What is noncommunicating hydrocephalus? |
Hydocephalus caused by an obstruction within the ventricles - most commonly: congenital aqueductal stenosis)
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Chap 2
What is communicating hydrocephalus? |
Hydroceph caused by blockage within the subarachnoid space (commonly caused by pus adhesions after meningitis)
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Chap 2
What is normal-pressure hydrocephalus? |
Hydroceph in adults caused when CSF is not absorbed by the arachnoid villi.
Clinical features: wacky, wobbly, wet (dementia from dilated ventricles, ataxic gait, urinary incontinence) |
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Chap 2
Hydrocephalus ex vacuo? |
A loss of cells in the caudate nucleus
Most common cause in Huntington's disease. |
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Chap 2
Three main functions of the CSF? |
CSF
1. protects against injury 2. transports hormones 3. removes metabolic waste products |
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Chap 2
RBC's in CSF = |
Subarachnoid hemorrhage
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Chap 2
What is an uncal herniation? |
FA p.367/HY p.25
When the uncus, the medial temporal lobe, herniates through the tentorial incisure. |
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Chap 2
What are the clinical signs assocated with uncal herniation? (4) |
FA p.367
Uncal herniation: 1. ipsilateral dilated pupil/ptosis: stretching of CN III 2. contralateral homonymous hemianopia: compression of ipsilateral posterior cerebral artery 3. ipsilateral paresis: compression of contralateral crus cerebri (Kernohan's notch) 4. duret hemorrhages - paramedian artery rupture: caudal displacement of brain stem. |
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Chap 2
Herniation figure: 1. anterior cerebral artery 2. subfalcial herniation 3. shifting of ventricles 4. posterior cerebral a 5. uncal herniation 6. Kernohan's notch, with damaged corticospinal and corticobulbar fibers 7. tentorium cerebelli 8. pyramidal cells that give rise to the corticospinal tract 9. tonsillar herniation with damage to medullary centers. |
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HY p.25 |
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Chap 2
Herniation syndromes (FA p.367) |
Herniation syndromes
1. Cingulate herniation: can compress anterior a 2. Downward transtentorial (central) herniation: coma and death result 3. Uncal: coma and death 4. Cerebellar tonsillar: herniation into foramen magnum |
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Chap 3
What does the anterior spinal artery supply? |
Anterior spinal artery:
1. anterior 2/3 of spinal cord 2. medulla's pyramid 3. medial lemniscus (also of medulla) 4. root fibers of CN 12 |
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Chap 3
What artery branches off the ophthalmic artery to feed the retina? What runs with the opthalmic artery? |
Opthalmic artery enters the orbit with the optic nerve (CN II). The central artery of the retina is a branch of the ophthalmic artery and occlusion of either causes blindness.
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Chap 3
What does the anterior cerebral artery supply? |
FA p.347
Anterior cerebral a: supplies medial surface of the brain - the area of the brain that controls the leg-foot area of motor and sensory cortices. |
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Chap 3
What does the middle cerebral artery supply? |
FA p.347
MCA: lateral aspect of brain, trunk-arm-face area of motor and sensory cortices as well as Broca's and Wernicke's speech area and frontal eye field |
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Chap 3
What does the anterior communicating artery do? |
FA p.347
The ACA is the most common cite of circle of willis aneurysm; lesions here can cause visual field defects. |
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Chap 3
Posterior communicating artery? |
FA p.347
PCA: other common aneurysm location, causes CN III palsy. |
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Chap 3
Lateral striate |
FA p.347
Lateral striate: branches of middle cerebral artery "arteries of stroke" supply the internal capsule, caudate nucleus, putamen, and globus pallidus |
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Chap 3
In general, a stroke of the anterior circle causes what? |
Anterior circle:
1. general sensory and motor dysfunction 2. aphasia |
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Chap 3
In general, a stroke of the posterior circle causes what? |
Posterior circle, FA p.347
1. cranial nerve deficits (vertigo, visual deficits) 2. coma 3. cerebellar deficits (ataxia) |
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Chap 3
What runs in the cavernous sinus? |
"OTOM CAT"
Oculomotor nerve (CN III) Trochlear nerve (CN IV) Ophthalmic nerve (V1 branch of trigeminal Maxillary nerve (V2 branch of the trigeminal) Carotid (internal) which has sympathetic fibers Abducens n. (CN VI) Tributaries (receives from superior and inferior opthalmic veins, sup. parietal sinus, and superior and middle cerebral veins. |
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Chap 3-WIKI
What is the clinical significance of the cavernous sinus? |
It is the only anatomic location in the body in which an artery travels completely through a venous structure.
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Chap 3 WIKI
What happens if the internal carotid artery ruptures within the cavernous sinus? |
An arteriovenous fistula is created and cavernous sinus syndrome may result from mass effect (also can happen from a tumor) and cause opthalmophegia (from compression of oculomotor, trochlear, and abducens n.; opthalmic and maxillary sensory loss).
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Chap 3, FA p.347
Describe where venous sinus' run? |
They run in the dura mater where its meningeal and periosteal layers separate.
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Chap 3, FA p.347
Describe the drainage patterns of the venous system in the brain. |
Cerebral veins --> venous sinus --> internal jugular veins.
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Chap 3
What is the middle meningeal artery a branch of and where does it enter through? |
Middle meningeal artery (is a branch of the maxillary a) and enters cranium through the foramen spinosum. It supplies most of the dura.
Laceration: epidural hemorrhage |
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Chap 4
What does the neural tube form? |
Neural tube gives rise to the central nervous system (ie brain and spinal cord)
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Chap 4
What are the two plates of the brain stem and spinal cord? |
Alar plate: gives rise to sensory neurons
Basal plate: gives rise to the motor neurons |
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Chap 4
The neural tube also gives rise to three primary vesicles which develop into what five secondary vesicles? |
1. Forebrain --> Telencephalon and Diencephalon
2. Midbrain --> mesencephalon 3. Hindbrain --> metencephalon and myelencephalon |
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Chap 4
The five secondary vesicles fetal neural development develop in to what? |
1. Telencephalon --> cerebral hemispheres / lateral ventricle
2. Diencephalon --> thalamus / third ventricle 3. Mesencephalon --> midbrain/aqueduct 4. Metencephalon --> pons and cerebellum/upper part of fourth ventricle 5. Myelencephalon --> medulla / lower part of fourth ventricle |
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Chap 4
What does failure of the anterior and posterior neuropores to close result in (respectively)? |
Anterior neuropore: anencephaly (failure of brain to develop)
Posterior neuropore: spina bifida |
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Chap 4, FA p.342
What are microglia? |
Microglia: CNS phagocytes from mesodermal origin. They have small irregular nuclei and very little cytoplasm. In response to tissue damage they transform into large ameboid phagocytic cells.
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Chap 4, FA p.342
Can you see microglia on Nissel stains? |
No
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Chap 4, FA p.342
What happens to the microglia in patients with HIV infection? |
The microglia of patients with an HIV infection fuse to form multinucleated giant cells in the CNS.
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Chap 4
When, in gestation, does myelination begin and end? |
Myelination begins in the fourth month of gestation and it is not complete until the end of the second postnatal year, when the tracts become functional. Myelination in the cerebral association cortex continues into the third decade.
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Chap 4
What myelinates the CNS? Where are these cells not seen? |
Oligodendrocytes myelinate the CNS.
They are not seen in the retina. |
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Chap 4, FA p.342
Oligodendrocytes? Appearance, function, stain? |
Oligodendrocytes: each on myelinates multiple CNS axons (up to 30 each). They stain in Nissel stains, appearing as small nuclei with dark chromatin and very little cytoplasm. They are the main glial cell in white matter.
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Chap 4, FA p.342
What cells are destroyed in multiple sclerosis? |
Oligodendrocytes mainly (myelinate multiple CNS axons)
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Chap 4, FA p.342
What myelinates the PNS? How many axons do they each myelinate? |
Schwann cells:
Each schwann cell myelinates only 1 PNS axon. |
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Chap 4, FA p.342
What is an example of a schwannoma and where are they found? |
Schwannoma: acoustic neuroma found in the internal acoustic meatus (CN VII, VIII)
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Chap 4, FA p.342
What cells line the ventricles? What cells in brain are involved in phagocytosis? What neuro cells originate from the ectoderm? |
Ependymal cells: line ventricles
Microglia: phagocytosis Ectoderm: all neuro cells except microglia which, like other macrophages, originate in the mesoderm. |
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Chap 4, p.342
What is the function of astrocytes? Marker? |
Astrocytes: provide physical support,
repair, K metabolism, help to maintain BBB Marker: GFAP |
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Chap 4
Where does the conus medullaris end in the newborn? |
Ends at the third lumbar vertebra (L3)
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Chap 4
Where does the conus medullaris end in the adult? |
Adult: L-1
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Chap 4
What is coloboma iridis caused by? |
A failure of the choroid fissure to close. This causes a defect in the iris.
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Chap 4
What is contained in the choroid fissure? |
All the optic nerve fibers
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Chap 4
Where did the optic nerve fibers derive from? |
Diencephalon
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Chap 4
Where did the adenohypophysis derive from? |
Adenohypophysis is derived from ectodermal mouth cavity called Rathke's pouch.
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Chap 4
Rathke's pouch gives rise to the adenohypophysis, what congenital cyst tumor can be formed from Rathke's pouch? |
Craniopharyngioma
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Chap 4
Where did the neurohypophysis develop from? |
Neurohypophysis developed from neural ectoderm of the neural tube causing the evagination of the hypothalamus.
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Chap 4
Cause of anencephaly (meroanencephaly)? |
Anencephaly: results from a failure of the anterior neuropore to close. As a result the brain does not develop.
Frequency: 1:1000 |
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Chap 4
Cause of spina bifida? |
Spina bifida results from a failure of the posterior neuropore to form.
Defect usually occurs in the sacrolumbar region. |
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Chap 4
What is spina bifida occulta? What percent of spina bifida is occulta? |
Spina bifida occulta: vertebral arches just don't touch but there are no meninges coming out.
10% of spina bifida is occulta. |
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Chap 3, p.355
In the cavernous sinus, which is the only nerve that is free floating? |
CN VI (abducens)
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Chap 3, FA p.355
Where is the cavernous sinus located in respect to the pituitary gland? |
The cavernous sinus forms on either side of the pitutary gland.
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Chap 3, p.355
What blood does the cavernous sinus house? |
Blood from eye and superficial cortex goes through the cavernous sinus into the internal jugular vein.
Also, the internal carotid a. runs through this sinus. |
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Chap 3, p.355
What bone is anterior to the cavernous sinus? |
Sphenoid bone
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Chap 3, p.355
Where do the nerves that control extraocular muscles pass through? |
The cavernous sinus.
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Chap 4
What is cranium bifidum? |
Cranium bifidum is a defect in the occipital bone through which meninges, cerebellar tissue, and the fourth ventricle may herniate.
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Chap 4
Arnold-Chiari malformation? |
Arnold-Chiari malformation:
- elongation of cerebellar tonsils so much that it pushes down through the base of the skull and blocks CNS flow - in almost all children with spina bifida and hydrocephalus - has a frequency of 1:1000 |
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Chap 5
Pseudounipolar neurons: |
Pseudounipolar neurons:
located in the spinal dorsal root ganglia and sensory ganglia of CN 5, 7, 9, and 10 |
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Chap 4
What is the Dandy-Walker malformation? |
Dandy-Walker:
Enormous enlargement of the fourth ventricle which is also associated with a small or absent cerebellum (compressed by fluid) and occipital cyst (meningiocele). Can be in IDed in infancy and can occur in older children. |
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Chap 4
Hydrocephalus Cause? |
Hydrocephalus:
MCC: stenosis of cerebral aqueduct during development Excessive CSF accumulates in the ventricles and subarachnoid space. Cause: can be caused by maternal infection (CMV or toxoplasmosis) Freq: 1:1000 |
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Chap 4
Fetal alcohol syndrome |
Fetal alcohol syndrome:
MCC of mental retardation Associated with microcephaly and congenital heart defects |
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Chap 4
Holoprosencephaly |
Holoprosencephaly: results from a failure of forebrain to develop (telencephalon and diencephalon = lateral and third ventricle, cerebral hemispheres, and thalamus).
The most severe manifestation of fetal alcohol syndrome. |
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Chap 4
Hydraencephaly |
Hydraencephaly:
results from bilateral hemispheric infarction secondary to occulsion of the carotid arteries. The hemispheres are replaced by hugely dilated ventricles. |
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Chap 5
Where are bipolar neurons found? |
Bipolar neurons are found in the cochlear and vestibular ganglia of CN VIII, in the olfactory nerve (CN I) and in the retina.
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Chap 5
Where are multipolar neurons found? |
Multipolar neurons are the largest population of the nerve cells in the nervous system.
This group includes motor neurons, ANS neurons, interneurons, pyramidal cells of cortex, and Purkinjie cells of cerebellar cortex. |
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Chap 5
What is Nissel substance? |
Nissel: it is a substance found in neurons that consists of rough ER (it makes protein)
It is found in the nerve cell body (perikaryon) and dendrites, not in the axon hillock or axon. |
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Chap 5
What is Wallerian degeneration? |
Wallerian degeneration: when any nerve fiber is cut or chushed there is anterograde degeneration characterized by the dissapearance of axons and myelin sheaths and the secondary proliferation of Schwann cells.
It occurs in the CNS and PNS. |
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Chap 5
What is chromatolysis? |
Chromatolysis:
After nerve damage, this is a loss of the Nissel substance and subsequent retrograde degeneration of neurons in the CNS and PNS. |
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Chap 5
How does nerve regeneration differ between the CNS and PNS? |
CNS: regeneration does not occur. Ex. no regen of optic nerve.
PNS: axon regeneration does occur. |
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Chap 5 (p.49)
Describe the process of nerve regeneration in the PNS? |
2 weeks after injury: there are fewer Nissel bodies in the neuron and macrophages consume the degenerating fiber and myelin sheath
3 weeks: schwann cells proliferate 3 months after injury: if there is organized growth of the schwann cells there is a successful nerve regeneration. |
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Chap 5
How do astrocytes protect capillaries, neurons, and synapses? |
Astrocytes project foot processes that envelop the basement membrane of capillaries, neurons, and synapses.
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Chap 5
What neurotransmitters do astrocytes metabolize? |
GABA, serotonin, glutamate
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Chap 5
What forms glial scars in damaged areas of the brain? |
Astrocytes
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Chap 5
What contains glial fibrillary acidic protein? |
Astrocytes: GFAP
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Chap 5
What nerve cell contains glutamine synthetase? |
Astrocytes (another marker for astrocytes, other than GFAP)
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Chap 5
What cells produce CSF? |
Ependymal cells (line ventricles)
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Chap 5
Where are schwann cells derived from? |
Schwann cells: from the neural crest
They are myelin-forming cells of the PNS (1:1) |
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Chap 5
What are Lewy bodies? |
Lewy bodies: neuronal inclusions that are characteristic of Parkinson's dz
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Chap 5
What are negri bodies? |
Negri bodies are intracellular inclusions caused by rabies. They are found in pyramidal cells of the hippocampus and the Purkinjie cells of cerebellum
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Chap 5
What are hirano bodies |
Intraneuronal, eosinophilic, rodlike inclusions that are found in the hippocampus of patients with Alzheimer's disease.
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Chap 5
What are neurfibrillary tangles |
Intracytoplasmic deneraged neurofilaments that are seen in patients with Alzheimers.
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Chap 5
What are cowdry type A inclusion bodies? |
Intranuclear inclusions that are found in the neurons and glial in herpes simplex encephalitis.
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Chap 5
What are nerve fibers Ia and Ib for? |
Ia: proprioception and muscle spindles
Ib: proprioception and golgi tendon organs Both: fastest (70-120m/sec) |
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Chap 5
What are the nerve fibers II and III for? |
II: touch, pressure, vibration
III: touch, pressure, fast pain, and temperature Speed: 12-70m/sec (II are faster) |
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Chap 5
What are the nerve fibers IV for? |
IV: slow pain and temperature, unmyelinated fibers
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Chap 5
What are A-alpha nerve fibers for? |
A-alpha: they innervate extrafusal muscle fibers (responsible for generating power of muscle -- mechanical movement). They form the motor unit and are in the ventral horn.
Speed: 15-120m/sec |
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Chap 5
What are A-gama nerve fibers for? |
Gamma nerve fibers - innervate intrafusal muscle fibers that comprise the muscle spindle. These fibers are separated from rest of muscle by a collagen sheath and have sensory receptors.
Intrafusal fibers function to judge position of muscle and rate it is changing. Speed: 10-45m/sec |
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Chap 5
Which autonomic nerve fibers are myelinated: preganglionic or postganglionic? |
Preganglionic: myelinated
Postganglionic: unmyelinated |
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Chap 5: FA, p.363
Glioblastoma multiforme (6 key points) |
1. MC primary brain tumor.
2. Life expectancy < 1 yr 3. Found in cerebral hemisphere 4. can cross corpus callosum (butterfly glioma) 5. stain astrocytes with GFAP 6. pseudopalisading tumor cells (border central areas of necrosis and hemorrhage) |
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Chap 5, FA: p.363
Meningioma: (6 key points) |
Meningioma:
1. benign, noninvasive tumor of the falx and convex and convexity of the hemisphere 2. 2nd most common primary BT 3. arises from arachnoid cells external to brain 4. resectable 5. has spindle cells concentrically arranded in a whorled pattern (psammoma bodies: laminated calcifications) 6. associated with NF-2 |
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Chap 5: FA: p.363
Schwannoma |
1. third most common BT
2. Schwann cell origin 3. often localized to 8th nerve (acoustic schwannoma) 4. resectable 5. associated with NF-2 |
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Chap 5, FA: p.363
Oligodendroglioma |
Oligodendroglioma:
1. rare 2. slow growing 3. most often in frontal lobes 4. "fried egg" cells - round nuclei with clear cytoplasm 5. often calcified |
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Chap 5, FA p.363
Pituitary adenoma (4 key points) |
Pituitary adenoma:
1. most common form is prolactin secreting 2. bitemporal hemianopia (due to pressure on optic chiasm) 3. hyper- hypopituitary 4. derived from Rathke's pouch |
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Chap 5, FA p.363
Pilocytic (low-grade) astrocytoma (4 key points) |
Pilocytic astrocytoma
1. diffusely infiltrating glioma in children 2. most often in the posterior fossa (between foramen magnum and tentorium cerebelli) 3. benign; good prognosis 4. has rosenthal fibers (eosinophilic corkscrew fibers) |
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Chap 5, FA p.363
Medulloblastoma (7 key points) |
Medulloblastoma:
1. highly malignant CEREBELLAR tumor 2. second most common posterior fossa tumor in children 3. can metatastasize through the CSF tracts 4. form of primitive neuroectodermal tumor (PNET) 5. can compress 4th ventricle = hydrocephalus 6. rosettes or perivascular pseudorosette pattern of cells 7. radiosensitive |
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Chap 5, FA p.363
Ependymoma (6 key points) |
Ependymoma:
1. ependymal cell tumor in children 2. most commonly found in 4th ventricle 3. can cause hydrocephalus 4. poor prognosis 5. characteristic perivascular pseudorosettes 6. rod-shaped blepharoplast (basal ciliary bodies) found near nucleus 7. 60% of spinal cord gliomas |
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Chap 5, FA p.363
Hemangioblastoma (4 key points) |
Hemangioblastoma:
1. most often cerebellar 2. associated with von Hippel-Lindau syndrome when seen with retinal angiomas 3. can produce erythropoietin leading to secondary polycythemia 4. foamy cells with high vascularity |
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Chap 5, FA p.363
Craniopharygioma: (6 key points) |
Craniopharyngioma:
1. benign tumor in children 2. confused with pituitary adenoma 3. can also cause bitemporal hemianopia 4. MC childhood supratentorial tumor 5. derived from remnants of Rathke's pouch 6. calfication is common |
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Chap 5, FA p.343
Meissner's corpusules |
Meissner's corpusles:
Small, encapsulated nerve endings found in dermis of palms, soles, and digits of skin. Light discriminatory touch of glabrous (hairless skin) |
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Chap 5, FA p.343
Pacinian corpusles |
Pacinian:
large, encapsulated nerve endings found in deeper layers of skin at ligaments, joint capsules, serous membranes, and mesenteries. Pressure, coarse touch, vibration, and tension. |
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Chap 5, FA p.343
Merkel's |
Merkel's
Cup shaped nerve endings (tactile disks) in dermis of fingertips, hair follicles, hard pallate. Involved in light, crude touch. |
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FA, p.342
What are the peripheral nerve fiber layers? |
1. endoneurium: surrounds only a single nerve fiber
2. perineurium (permeability barrier): surrounds a fascicle of nerve fibers (Perineurium = Permeability barrier, must be rejoined in microsurgery for limb reattachment) 3. Epineurium (dense connective tissue): surrounds entire nerve (multiple fascicles and blood vessels) |
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Chap 5, FA p.343
What are the two type of free nerve fibers? |
Free nerve fibers:
1. nociceptors: pain 2. thermoreceptors: cold and heat |
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Chap 5, FA p.343
What sensory corpusle is not encapsulated? |
Merkel's
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Chapter 5: Case 2
4 yo girl presents with clumsiness and headaches. What tumor is most likely? |
Cerebellar astrocytoma (pilocytic astrocytoma: most common in posterior fossa)
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Chap 5, p.363, Case 3
63yo female presents with headaches and left-hemiparasis. Tumor cells crossing the corpus callosum can be seen on CT. And can see "psuedopalisading" tumor cells. What tumor? |
Glioblastoma multiforme
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Chap 5, p.363, Case 4
53 yo man with severe headaches. CT shows calficiation and hemorrhage in temporal lobe (could also be in frontal lobe). Tumor? |
Oligodendroglioma - mosre likely to show calficifation and hemorrhage than astrocytomas, common in temporal (HY) and common in frontal (FA).
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Chap 5, p.363
7yo boy with brain tumor biopsy containing rosenthal fibers: Tumor? |
Pilocytic astrocytoma
(Rosenthal fibers: eosinophilic corkscrew fibers) |
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Chap 5, p.363, Case 5
2yo girl with nausea and vomiting. Hydrocephaly is seen in lateral ventricle. Periventricular edema is seen along lateral ventricle. Tumor? Where is it most commonly seen? |
Malignant ependymoma:
most common in 4th ventricle |
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Chap 5, p.363: Case 6
44yo women with headaches. CT shows a tumor with "dural tails". Tumor? |
Meningioma:
slow growing and noninvasive (Case 8 on p.57 shows meningioma at cerebellopontine angle) |
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Chap 5, p.363: Case 7
38 yo women with ipsilateral hearing loss, tinnitus, and cerebellar ataxia. Tumor? |
Acoustic schwannoma:
p.57: white arrows show expanded interal auditory meatus. |
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Chap 5, p.363: Case 9
9 yo girl with ataxia, diplopia, and headaches. What is the DDX? If this tumor is seen in the cerebellum what is the Dx? |
DDx: astrocytoma, ependymoma, hemangioblastoma, and chroid plexus papilloma (not craniopharygioma because of no bitemporal hemianopia)
Dx: medulloblastoma |
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Chap 5, p.363: Case 10
38 yo man with blurred vision and CT with expanded sella turcica: Tumor? What are side effects? |
Pituitary adenoma: side effects most commonly are prolactin secretion: impotence!!!
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Chap 5, p.363: Case 11
8 yo girl with headache, weight gain, and anosmia with bitemporal hemianopia. Tumor? |
Craniopharyngioma: these tumors (in children) compress chiasm, pituitary gland (probably stopping TSH release), and third ventricle.
Most common childhood supratentorial tumor. |
