W2 - Blood supply Flashcards
What is the meaning of anastomosis?
Two arteries join together
What is the circle made from many anastomosis called?
Circle of Willis
The brain is 2% of the body’s weight, what percentage of oxygen received and cardiac output does the brain get?
20% of oxygen, 15% of cardiac output
What is different about the arteries and veins of the brain?
Artery walls are thinner and veins have no elastic layer and valves
What is autoregulation in the brain’s blood flow?
It remains constant despite changes in systemic blood pressure
What works to maintain the blood flow in the brain?
The dilation and constriction of arterioles mediated by astrocytes in active areas
From left to right (looking in anatomical position) list the branches from the aortic arch
Left subclavian, Left common carotid and brachiocephalic (R subcl + CC)
What is the artery that arises from the subclavian arteries?
Vertebral arteries
What 2 arteries arise from the common carotid arteries
Internal and external carotids
Which artery arises from the two vertebral arteries that goes down the spinal cord?
Anterior spinal artery
ANT CIRC - Where does the opthalmic artery supply and come from?
Orbit and retina - branches off of the internal carotid artery
Are the superior, anterior inferior and posterior inferior cerebellar arteries a part of the anterior or posterior circulation
Posterior
ANT CIRC - Where does the anterior choroidal artery supply and come from?
Choroidal plexus of lateral + 3rd ventricles, internal capsule and dien/telencephalic structures - branches off internal carotid artery
Which arteries anastomose and make up the barrier between the anterior and posterior blood flow?
Anterior part - posterior communicating arteries, posterior part - posterior cerebral arteries
ANT CIRC - Where does the anterior cerebral artery supply and come from?
Medial + superior frontal lobe, anterior parietal lobe - branches off internal carotid artery
75% or 25% of the blood flow, anterior or posterior and fed by what arteries?
75% - anterior via internal carotids, 25% - posterior via subclavian arteries
ANT CIRC - Where does the middle cerebral artery supply and come from?
Lateral + inferior frontal lobe, anterior lateral parietal lobe - branches off internal carotid artery
ANT CIRC - Where does the anterior communication artery supply and come from?
Optic chiasm - branches from anterior cerebral artery
ANT CIRC - where does the opthalmic artery supply and come from?
Orbit + retina - is a branch of the internal carotid
ANT CIRC - What is the posterior communicating artery?
Point of connection between ANT and POST circulatory systems
ANT CIRC - where does the anterior choroidal artery supply and come from?
Choroidal plexus of lateral + 3rd ventricles, internal capsule - branch of internal carotid
ANT CIRC - where does the anterior cerebral artery supply and come from?
Medial + anterior frontal and anterior parietal - branch of internal carotid
ANT CIRC - where does the middle cerebral artery supply and come from?
Lateral + inferior frontal and anterior lateral parietal
The striate arteries come from the middle cerebral artery, what two structures do they supply?
Basal ganglia and internal capsule
ANT CIRC - where does the anterior communicating artery supply and come from?
Optic chiasm - branch of anterior cerebral artery
ANT CIRC - what does the posterior communicating artery do?
Creates border for anterior/posterior circulation with the posterior cerebral artery
POST CIRC - where does the posterior cerebral artery supply and come from?
Supplies mesencephalon, occipital lobe and posterior + medial temporal lobe - branches off of basilar artery
POST CIRC - where does the basilar artery supply and come from?
Supplies pons - comes from both vertebral arteries coming together
POST CIRC - where does the anterior inferior cerebellar artery (AICA) supply and come from?
Supplies cerebellum - branches from the basilar artery
POST CIRC - where does the vertebral arteries apply and come from?
Supplies spinal cord and medulla oblongata - vertebral arises from subclavian arteries
POST CIRC - where does the posterior inferior cerebellar artery (PICA) supply and come from?
Supplies dorsal medulla and cerebellum via PICA - branches off of vertebral arteries
How many spinal arteries are there?
2 - posterior, 1 - anterior
Which side of the brainstem is the posterior circulatory system?
Ventral
Does everyone have the classic circle of willis?
No only about 33%
Collateral blood supply means…
There are alternate/backup arteries/veins that can take over when another is blocked up or damaged (e.g. between MCA + ACA)
What two arteries affect the homunculus?
ACA (anterior cerebral) and MCA (middle cerebral)
At lower levels, the anterior/posterior spinal arteries that supply the SC are supplied themselves by what artery?
Radicular
Which sinus empties into the jugular vein?
Sigmoid sinus
What venous structures are involved with draining from the brain and spinal cord?
Brain - dural venous sinuses (then sigmoid) and Spinal cord - spinal veins
