brain blood supply Flashcards
what are the 2 main arteries that supply the other branches of the brain
internal carotid arteries and the vertebral arteries
what arteries branch off the internal carotid
middle cerebral artery and the anterior cerebral arteries
what makes up the circle of willis? why is the circle important
ensures if a stroke occurs, the blood can recirculate around the circle to make sure that the brain continues to receive blood and that cell death is kept to a minimum
made up of the ACA, anterior communicating artery, internal carotid arteries, posterior communicating arteries, and the posterior cerebral arteries
What do the basilar arteries supply
brainstem
what does the MCA supply
lateral portions of the brain (parts of the parietal and temporal)
what does the ACA supply
medial aspects of the brain
what does the anterior/posterior inferior cerebellar arteries supply
anterior and posterior aspects of the cerebellum
what does the posterior cerebelar artery supply
occipital lobe mainly
What is the blood brain barrier and why is it important
protects the brain from harmful substances and fluctuations of solutes
allows essential solutes to pass however, like glucose and essential amino acids. also removes wastes from the brain and into the bloodstream
if the constants of the ions and solutes change in the brain, could result in issues with neuronal firing as some ions are used as neurotransmitters. would lead to uncontrollable inputs and spastic firing
not protective against lipid soluble molecules (anything hydrophobic) like fats, fatty acids, O2 and CO2
what are pericytes
help maintain the BBB by communicating with the endothelial cells
what are circumventricular organs
areas that lack a BBB, like the posterior pituitary gland, pineal gland, (endocrine glands) and the area postrema (controls vomiting by monitoring for excess poisonous substances)
why dont circumventricular organs have a BBB
require direct access to the bloodstream cause they regulate the body’s hormones, metabolic functions, and reflexes.
what are the 3 functions of the CSF
protection - cushion around the brain
transport - helps supply nutrients to the brain and remove wastes
support - the brain floats in the CSF, reducing its weight to prevent soft neuronal tissue from being crushed
what is the composition of CSF
blood plasma mainly, but also includes lower K+ concentrations and lower amino acids, significantly lower than blood plasma
what is the choroid plexus
cells in the ventricular system that produce CSF while also filtering out wastes, extra NTs, and foreign substances out the CSF
produce about 500ml of CSF a day
