Lecture 7 part II Flashcards
What happens if there is an occlusion in the anterior/posterior spinal arteries
Loss of spinal cord function at level of occlusion (paralysis, loss of sensation, etc)
What happens if there is an occlusion in the posterior inferior cerebellar artery (PICA)
Wallenberg syndrome: Loss of pain and temperature sensation on contralateral side of body/torso, and ipsilateral side of face
What happens if there is an occlusion in the anterior inferior cerebellar artery (AICA)
Lateral Pontine syndrom: sudden onset of vomiting/vertigo, Ipsilateral loss of sensation to face and ipsilateral face paralysis
What happens if there is an occlusion in the superior cerebellar artery
Ipsilateral limb dysmetria, contralateral loss of sensation
What happens if there is an occlusion in the Pontine artery
contralateral paralysis and loss of sensation. Often results in death, depends on size of infarct
What happens if there is an occlusion in the labyrinthins artery
ipsilateral hearing loss and vertigo
What is the circle of willis
Communicating branches form anastomoses between cerebral aa
Where is the middle cerebral artery
along the lateral fissure (sylvian sulcus) and lateral surface of cerebral cortex
What happens if there is a stroke in a cortical branch of the middle cerebral artery
Because the branches go to the lateral surface of the cortex, there is often contralateral paralysis and sensory loss, and aphasia if it was on the dominant side
What happens if there is an occlusion in a lateral striate branch of the middle artery
Because they supply internal capsule and basal ganglia, hemiplegia often results
What does the posterior cerebral artery supply
occipital and temporal lobes
What happens if there is an occlusion in the posterior cerebral artery
Visual field defects, prosopagnosia, contralateral deficits of CN VII, X, XII, and ipsilateral deficits of CN III
What happens if there is an occlusion in the anterior cerebral artery
contralateral paralysis and sensory loss in leg and foot, Abulia: lack of will or initiative. pronounced passivity, reduced social interactions, emotional responsiveness
What direction does blood from cerebral hemispheres and brain stem drain
Outwards into surface veins
How does blood get to the dural sinuses
cerebral veins drain it there
What is a dural sinus
venous compartment within the dura mater
What are the dural sinuses associated with the falx cerebri
Superior sagittal, inferior sagittal, straight
<p>What are the dural sinuses associated with the tentorium cerebelli</p>
<p>Straight, confluens, transverse, sigmoid</p>
What are the dural sinuses associated with the anterior cranial base
Cavernous, inferior and superior petrosal sinuses
Where is the cavernous sinus
On either side of the sella tursica surrounding the pituitary gland
What is the function of the cavernous sinus
Receives blood from local sinuses, orbital veins, and communicates with the pterygoid plexus in the lateral pterygoid muscles
What is the function of the superior and inferior petrosal sinuses
Drain blood from cavernous sinus posteriorly into transverse sinus
What passes through the cavernous sinus
Internal carotid, CN III, IV, V, VI
What are the anterior and posterior longitudinal sinuses
Valveless veins around dura in spine
What is the basivertebral vein
Drains the vertebral body and is route of metastasis for prostate cancer to spine
What are emissary veins
Vein that allow blood to flow freely between scalp and dural sinuses
What is the function of emissary veins
Helps thermoregulate the brain by shunting hot blood to the surface in hyperthermia
What cells make up the blood brain barrier
endothelium, pericytes, astrocyte feet, and basal lamina
What does the blood brain barrier filter out
large, water soluble molecules
How is the blood brain barrier maintained
astrocyte feet induce and maintain tight junctions between capillary endothelial cells
How does glucose and amino acids reach the brain
They penetrate endothelial cells via transporters
How do gases reach the brain
They diffuse (as always)
What part of the brain is not protected by the Blood brain barrier
The hypothalamus, area postrema and other periventricular regions (limbic system)
What is the import of some regions of the brain not being protected by the blood brain barrier
passage of larger molecules, hormones can contact the hypothalamus, poisons can stimulate pathway to vomit center
What is the blood CSF barrier
tight junctions between choroidal epithelial cells making it impermeable to larger molecules
What is the brain CSF barrier
free movement between the brain interstitium and ventricles through ependymal cells
What type of substance can go through any of the barriers in the brain
lipophilic substances like alcohol, anesthetics
