Lecture 4 Flashcards
Where is CSF formed?
Choroid plexus
What is the purpose of CSF?
Clear waste, supply nutrients
Provide shock absorption to brain
What is the shape of the lateral ventricles?
The first 2 ventricles are C-Shaped lateral ventricles
Where is the 3rd ventricle of the brain located?
Midline of the diencephalon (thalamus and hypothalamus)
It is surrounded by the thalamus and hypothalamus
Where is the 4th ventricle located?
Posterior to pons/medulla, but anterior to cerebellum
What is the foramina of monro
Where the 2 C shaped lateral ventricles connect to the 3rd ventricle
What are the 2 inner layers of the dura mater?
Falx Cerebi
Tentorium Cerebelli
The inner and outer layer of the dura mater is fused except at the _____ which collect CSF and venous blood
Dural sinuses
The villi/granulations of arachnoid mater do what?
go through dura into venous sinuses to allow CSF to flow into them
What are the 3 layers of the Choroid plexus that turns blood into CSF
- Capillaries
- Connective tissue
- Epithelial cells
True or false: CSF is a protein rich substance
True
What is the most common cause of a epidural hematoma
Due to fx of parietal or temporal bone tearing the middle meningeal artery
What kind of hematoma has a quick cumulation of blood, and presents with a period of lucidity followed by quick deterioraiton
epidural hematoma
What kind of hematoma is most often caused by venous bleeding and presents as a slow progressive deterioration
subdural hematoma
(not subdural hemorrhage)
Congenital or acquired Hydrocephalus
**Abnormal build up of CSF in ventricles
**
Infants with nonfused skulls will have enlarged heads
Children/adults with fused skull will have excessive pressure on white matter
What is communicating hydrocephalus
When ventricular system is intact with blockage caudal to 4th ventricle
Basically the ventricular system can still communicate, but it cannot leave ventricals
What is noncommunicating/obstructive hydrocephalus
Blockage within ventricular system/ usually in the cerebral aqueduct
Meningitis has pain that increases with…
Upright position
Head movement
Sneezing/coughing
How many arteries supply the anterior spinal cord?
How many supply the posterior spinal cord?
1 “anterior spinal artery”
2 “posterior spinal arteries”
What is the circle of willis?
Circular arteries that supply blood to brain
The vertebral arteries fuse to form what?
Basilar artery
The basilar artery feeds into what
The posterior cerebral arteries and superior cerebellar arteries
What is the parent structure of the posterior choroidal artery
Posterior cerebral artery
What regions of the spinal cord get the most blood supply?
Cervical and lumbar
Arteriovenous Malformation
Congenital
Arteries connect to abnormal vessels rather than capillaries and veins
Symptoms include local pain, can be found anywhere in body
What is the most common kind of aneurysm
Sacular aneurysm
Aneurysms worsen with…
Age and Hypertension
Why can’t parkingson’s patients take dopamine to help them?
Because it cannot pass the blood brain barrier, so they must take a precursor that can
What is the role of the pericyte cell?
Guards the blood brain barrier
What parts of the brain are not protected by the bloodbrain barrier?
Areas that sample the blood or secrete things into the blood
Parts of hypothalamus and other areas close to 3rd/4th ventricle
What causes cerebral arteries to dialate?
Relating to: BP, O2, PH, CO2, Lactic Acid…..
BP, O2, or pH levels are too low
OR CO2/Lactic acid is too high
If the inverse is true they constrict
O2 use increases from brainstem to
cerebral cortices
The cortex is more vunerable to O2 loss than…
The Life centers of brain stem
note:explains why people can live in persistent vegitative state for long time
What is cerebral edema?
excessive fluid in brain
What are 3 common causes of Cerebral edema
TBI, including concussion
Heart attack
High Altitude cerebral edema (HACE)
Why is cerebral edema often progressive
Because fluid pressure causes ischemia and then arterioles dilate to deliver more oxygen but this leads to even more capillary pressure and edema
What is the normal range of intracranial pressure?
5-15mmHG
Above 15 is abnormal and above 20 is pathological
Above 20 is contraindication for PT
Where is intracranial pressure monitored?
measured by monitor in lateral ventricle
Pressure against falx cerebri is likely to cause what? (Homunculus)
Issues at contralateral lower limb
Note: because it’s more medial and that is where the lower limb is located on the homunculus
A cingulate herniation puts pressure on what?
Falx cerebri
An Uncal herniation puts pressure on what?
Midbrain, causing Cranial nerve 3 dysfunction and loss of conciousness
a central brain herniation puts pressure against what
Against diencephalon, moving it and the midbrain/pons down
Can stretch basilar artery and cause ischemia, paraylsis and impaired conciousness and oculomotor function
A Tonsillar brain herniation causes what
Pressure on cerebellar tonsils, can impair conciousness
superficial veins drain cortex and white matter blood into the _____-
whereas deep veins drain basal ganglia, diancephalon, and white matter blood into the ______
Superior Saggital Sinus
Straight sinus
Where do the saggital sinus and the straight sinus meet?
At the confluence of sinuses
What arises from the confluence of sinuses and drains into the jugular vein?
The transverse sinus
What is a TIA (transient ischemic attack)
Brief localized loss of brain function
resolves in 24 hours
Medical emergency due to likelihood of future stroke
A stroke is a cerebral vascular accident lasting longer than…
One day
80% of all strokes are..
Infarcts (instead of hemorrage)
What artery do most infarct strokes affect?
Middle cerebral artery
What is the difference between embolus and thrombus
Embolus- clot traveled from somewhere else, quick onset
Thrombus- builds up over time
What is a lacunar infarct?
small deep circulation infarct
20% of all strokes are
Hemorrage strokes
-Sudden loss of function, severe headache/ loss of consiousness
Complete blockage of the basilar artery causes
death due to ischemia of brainstem
Vertebral arteries are prone to ______ force injuries due to abrupt cervical rotation or extension
shear force
Partial blockage of the basilar artery can cause….
tetraplegia, numbness, loss of consciousness, cranial nerve damage
Locked in syndrome
Anterior cerebral artery stroke are likely to cause….
Contralateral lower extremity issues
Personality changes
Middle cerebral artery strokes are likely to cause
Language defects in the L brain
Spatial awareness defects/ nonverbal communication in the R brain
Also affects contralateral face and upper extremity
A posterior cerebral stroke can cause….
Loss of Eye movements
Cortical blindness
declarative memory (hippocampus)
Pain, hemiparesis, hemisensory loss (thalamus)
Watershed areas of the brain are vulnerable to _______
border-zone regions in the brain supplied by the major cerebral arteries where blood supply is decreased
Vulnerable to ischemia
identify this herniation and what tissue does it press against
cingulate herniation
pressure against falx cerebri
Identify this herniation and what it causes
Uncus hernation
causes pressure to midbrain and CN3
loss of conciousness
Identify this herniation and what it causes
Central herniation
Pressure against midbrain moving it and pons down
Impaired oculomotor function, stretching of basiliar artery
Identify this herniation and what it causes
Tonsillar herniation
pressure on brainstem
What do they use to drain fluid from a patient with hydrocephalus
ventriculoperitoneal shunt
What 2 structures receive the most dedicated space in the motor homunculus
Face and hands
What structures have the most dedicated space on the sensory homunculus
The lips/tongue/throat
also the feet
True or false: The distribution between body parts of the sensory/motor in the homunculus is fixed when you’re born
False, it changes based on the amount of sensory received in your life
example: if you lose your hand that part will shrink
Take a moment to review the venous flow
Good work soldier
What kind of herniation puts pressure on CN3?
Uncal herniation
