CSF and Circulation (1) Flashcards
Where and by what is CSF produced?
choroid plexus in the lateral and 3rd ventricles mostly but a little in the 4th ventricle as well
What is the flow of CSF?
lateral thru interventricular foramen (Monroe) to the 3rd thru cerebral aqueduct to the 4th then either out foramen of Magende into cerebromedullary cistern up to cistern of great cerebral vein or spinal column down to the lumbar cistern; or out the foramen Luschka to pontine cistern up to interpeduncular cistern
How do the choroid plexus cells create CSF? How can you clinically decrease CSF production?
Pulls Na, Cl, HCO3 and H2O out; CA inside the cells makes HCO3 out of H2O and CO2 and pumps it out of both sides; can inhibit CA
What are the components of the blood brain barrier?
tight junctions in capillary endothelium, tight junctions between choroid plexus cells, tight junctions in the arachnoid membrane, the ependymal next to the circumventricular organs; glia and astrocytes induce the tight junctions of the arteries but are not the BBB
What is the composition of CSF macromolecules?
small proteins, much less than blood, lipophilic substances diffuse more readily than hydrophilic, facilitated diffusion- glucose and certain AA
What is the function of CSF?
preserve brain homeostasis, mechanical protection- reduces effective brain weight (buoyant), pathway for removal of metabolites
When is brain metabolites cleared mostly?
at night during sleep
What are the different types of hydrocephalus?
non-communicating: obstruction within ventricular system, communicating: obstruction within subarachnoid space
What are the features of aqueductal stenosis?
obstruction at level of cerebral aqueduct, bulging fontanel, and split sutures, craniofacial distortion
What is the dandy-walker malformation?
obstruction at the outlet of the 4th ventricle plus cerebellar hypoplasia, often associated with malformations of other parts of the brain
What is a Chiari malformation?
small posterior fossa, tonsils well below foramen magnum, stenosis of cerebral aqueduct often with it, 90% with a myelomeningocele
What are the common causes of acquired hydrocephalus?
tumor, hemorrhage, or infection
If there is an obstruction of CSF where is there dilation?
proximal to the obstruction
What are the cerebral branches off the internal carotid?
middle cerebral, anterior cerebral, posterior communicating
What are the branches off of the middle cerebral artery?
lenticulostriate (several small)
What are the branches off of the anterior cerebral?
anterior communicating, medial striate, and pericollassal artery
What are the components of the circle of willis?
posterior cerebral, posterior communicating, internal carotid, anterior cerebral, and anterior communicating
What are the branches of the vertebral arteries?
join to form basilar, posterior inferior cerebellar, a joint anterior spinal
What are the branches off the basilar inferior to superior?
anterior inferior cerebellar, internal acoustic, several pontine, superior cerebellar and posterior cerebral
What are the branches off of the posterior cerebral?
posterior communicating
where is the posterior spinal artery found? Supplies?
parallel to posterolateral sulci, supplies the dorsal funiculus, portion of lateral funiculi, and the posterior horn
Where is the anterior spinal artery found? what does it supply?
along the anterior median fissure, ventral and much of the lateral funiculi, and anterior gray matter, gives of sulcal arteries
What arteries also supply the spinal cord? What do they branch from?
radicular branches, from vertebrals, ascending cervicals, intercostals, and lumbar arteries, not at all levels, run along with exiting spinal nerves
Where is the great vein of Galen?
empties into the meeting of inferior sagittal sinus and straight sinus, deep
Where is the inferior anastomotic vein located?
aka Labbe, runs along the lateral sulcus and empties into the transverse sinus
Where does the superior anastomotic vein run?
along central sulcus connecting superior sagittal sinus with inferior anastomotic vein of Labbe
Where does the cavernous sinus drain to?
2 paths one to the transverse sinus and the second to the sigmoid sinus
What are the veins along the posterior of the spinal cord?
posterior spinal vein running along the posterior median sulcus, two posterolateral spinal veins running by the posterior spinal arteries
What are the veins along the anterior spinal cord?
anterior spinal vein along the anterior spinal artery
Where do the anterior and posterior spinal veins drain?
radicular veins into a plexus of veins in the epidural space, through vertebral foramina to external plexus to lumbar, vertebral and intercostal veins
