Exam 3 content 2 Flashcards
What does SCALP stand for
Skin Connective tissue Aponeuroses Loose connective tissue Pericardium
What are the meninges of the brain
Durra
Arachnoid
Pia
Describe the durra mater and what structures it forms
Thickest Toughest Outermost Falx cerebri Tentorium cerebelli
What can the dura mater damage in traumatic incidents
Falx - Corpus calosum
Tentorium - CN3, brainstem
Describe the epidural space and some of its contents
Between skull and durra
Middle meningeal artery
Describe a epidural hematoma
Rupture of the middle meningeal artery
May shift brain over
Describe the subdural space
Between the dura and arachnoid
Describe a subdural hematoma
Chronic - rupture of bridging veins that are vulnerable to shear forces
Acute - traumatic shear force
Describe the subarachnoid space
Between the arachnoid and pia mater
Describe subarachnoid hematoma
Bleeding into the CSF
May be traumatic or non traumatic
Produces severe headaches
What is a Subfalcine herniation
Brain pushed under falx cerebri
What is a central herniation
brain pushed into 3rd ventricle
What is an uncal herniation
Pushes brain over lip of tentorium cerebelli
What is a tonsillar herniation
Cerebellar tonsil pushed through foramen magnum
Briefly describe the lateral ventricles
C shaped with a tail
Exist in all lobes of the brain
Describe the Luschka and Magendi canal
Luschka - lateral off of 4th
Magendi - posterior off of 4th
What is the role of the choroid plexus and what is it made of
Produce CSF
Ependymal cells
What is the role of CSF
Buoyancy
Cushioning
Cleaning
Ionic balance
Where is the cistern magna
Between cerebellum and medulla
what is normal CSF pressure in adults
80-180 mm of water
Describe the arachnoid granulations
CSF is constantly produced and needs to be removed
Exits via the arachnoid granulations and deposited into venous sinus
What is hydrocephalus, how is it caused, how is it treated
Enlarged ventricles due to increased CSF pressure
Blocked CSF circulation, impeded CSF absorption, too much CSF production
Treated with shunt to drain CSF
What are some symptoms and treatments of increased ICP
Headache, nausea, bradycardia, hypertension, loss of consciousness, papilledema
Head elevation in bed, medication, surgery to remove part of the skull
Describe a lumbar puncture
L3-L5
Fetal position
Epidural space
Describe venous drainage of the brain
Superior sagittal sinus Inferior sagittal sinus - strait sinus Confluence Transverse Sigmoid IJV
Describe the blood brain barrier
Tight junctions between endothelial cells and capillary wall
Protect brain function
What can a sudden explosive headache indicate
Medical emergency
Stroke
CSF increases
Where does the anterior and posterior circulation of the brain originate from
Anterior - carotid
Posterior - vertebral arteries
What is an aneurysm
Sack protrusion on the side of a blood vessel
Describe a transient ischemic attack
Brief period of stroke symptoms, less than 10 minutes
15% of patients with TIA will have CVA - 50% of those CVAs will happen in 48 hours
What is apraxia and agnosia
Apraxia - difficulty with leaned movement
Agnosia - inability to recognize objects by touch
What is the rule of 2s in the brain
Brain is 2% of body weight
Uses 20% of the oxygen
Uses 25% of the glucose
receives 15% of cardiac output
What is TPA
Ischemic stroke medication
to be given within 4.5 hours of stroke
Describe hemorrhagic stroke
15%-20% of strokes
Higher mortality than embolic strokes or thrombic
The larger the vessel the larger the mortality
How do you recognize a brainstem stroke
4D’s with crossed findings
- Diplopia
- Dysarthria
- Dysphagia
- Dizziness
Contralateral
- Weakness
- Sensory loss
- Cerebellar signs
Describe locked in syndrome
Basilar artery stroke
Bilateral weakness of UE, LE and face
Lateral gaze weakness
Dysarthria
Describe the fovea
Central fixation point for each eye
Surrounded by the macula
What creates a blind spot
The optic disk of an eye that is used by itself
What are the layers of the retina
Photoreceptors - Rods - low light conditions, no color - Cones - High resolution images Bipolar cells - send info to ganglion cells Ganglion cells - Parasol cells - large movements / gross features - Midget cells - fine visual details and color
What is the LGN
Lateral geniculate nucleus
Where the optic tracts go
What are the layers of the LGN
Parvocellular layers - 6-3 - midget cells
Magnocellular layers - 2-1 - Parasol cells
What is an extra geniculate pathway
Optic nerve fibers that bypass the LGN and instead enter the colliculus and pretectal areas
Describe Meyer’s loop
Superior Visual field
Inferior optic radiations
Pass through temporal lobe
To lower bank of calcarine
Describe the superior radiations
Inferior visual field
Pass through parietal lobe
Upper bank of calcarine
Where is the Fovea and macula represented in the cortex
Occipital pole
How does the body process motion imaging
Motion
- Parasol cells
- Dorsolateral cortex
- “Where is what we are seeing”
How does the body process form and color imaging
Form and Color
- Midget cells
- Inferior Occipital Temporal cortex
- “What are we looking at”
What is the difference between positive and negative visual phenomena
Positive
- things added to visual field, hallucinations or colors
Negative
- loss of visual field
What is the result if there is damage to the optic nerve
Monoptic visual loss
What is the result if there is a scotoma present
damage to a small part of the retina
What is the result if there is damage to the optic chiasm
Bitemporal hemianopsia “tunnel vision”
What is the result if there is damage to the Optic tract, LGN, both optic radiations, Primary visual cortex
Homonymous hemianopsia
What is the result if there is damage to the Superior radiations or upper back of calcarine
Contralateral inferior quadrantanopia
What is the result if there is damage to the Inferior radiations or inferior bank of the calcarine
Contralateral superior quadrantanopia
Describe Macular sparing
partial lesions of visual pathway result in intact macular tracts
Center of vision is still intact
Describe Central scotoma
Occipital lobe damage
Resulting in loss of only the very center of the visual field
Describe a Amaurosis Fugax
Transient occlusion of inferior branch of retinal artery
Browning out
Refer this patient out
