martin chapter 3 Flashcards
transient ischemic attack
brief reduction of blood flow
produces transient neurological signs
infarction
death of the tissue due to lack of blood supply
ischemic stroke
Ischemic stroke occurs when there is a blockage in a blood vessel that supplies blood to the brain, resulting in a reduction of oxygen and nutrients to brain tissue. This leads to neuronal damage and, if not promptly treated, tissue death (infarction).
hemorragic stroke
when an artery ruptures thereby releasing blood into the surrounding tissues.
consequences
-loss of downstream flow
-damage to the tissues surrounding the rupture due to the release of blood
anterior brain circulation is fed by?
the internal carotid artery
the anterior circulation is also called carotid circulation
posterior brain circulation is fed by?
vertebral artery
the posterior circulation is also called vertebral basilar circulation.
The vertebral arteries join and form the basilar artery at the pontomedullary junction->the junction between the medulla and the pons.
the brain stem receives blood from which of the 2 circulations?
by the posterior circulation
the hemispheres instead by both anterior and posterior
the arterial supply for the spinal cord is supplied by which circulation?
the systemic circulation
is also provided (at a lesser degree) by the vertebral arteries
the spinal cord receives blood from 2 sources
- anterior and posterior spinal arteries, branches of the vertebral arteries
- radicular arteries, which are branches of intercostal, lumbar and cervical arteries
artery of Adamkiewicz
particular important radicular artery that supplies the lower portion of the spinal cord (caudal to T8)
3 groups of arteries arise from the vertebral and basilar arteries to supply brain stem and cerebellum
paramedial branches, for regions of brain stem close to the midline
short circumferential for lateral regions of brain stem
long circumferential for dorsal regions of brain stem and cerebellum
posterior inferior cerebellar artery
its a long circumferential artery
nourishes the most dorsolateral region of the medulla
this region of the medulla does not receive any other arteries so occlusion in the PICA would result in serious consequences.
do spinal arteries supply the medulla?
yes, the most medial medulla is supplied by spinal arteries
the rest of the medulla is supplied by vertebral arteries
pons vascularization
base= supplied by paramedian and short circumferential arteries
dorsolateral surface: anterior inferior cerebellar artery
rostral to dorsolateral surface: by superior cerebellar artery
AICA and SCA are long circumferential arteries
cerebellum vascularization
supplied by long circunferential branches of the vertebral and basilar aaretries
PICA supplies the caudal portion
AICA and SCA supply more rostral regions of the cerebellum
the basilar artery at the pons-midbrain splits into
the two posterior cerebral arteries
midbrain vascularization
posterior cerebral artery vascularizes most of the midbrain. paramedial and short circumferential branches supply the base and tegmentum, while long circumferential branches supply the tectum.
the colliculi, most important part of the tectum, receive vascularization from the SCA
4 segments of the internal carotid artery
- cervical portion: from common carotid artery bifurcation till the entrance in the carotid canal
- intrapetrosal segment: the portion that passes in the petrous portion of the temporal bone
- intracavernous segment: the portion that passes inside the cavernous sinuses (that overlies the sphenoid bone)
- cerebral segment: till the bifurcation into anterior and middle cerebral artery
what makes the carotid siphon and what is it?
an important radiological landmark and is made by the cerebral and intracavernous portions of the internal carotid artery
3 main branches of the cerebral segment of the internal carotid artery (caudal to rostral)
ophtalmic artery
posterior communicating branch
anterior choroidal artery
what do the deep branches of the 3 cerebral arteries and the branches of the cerebral portion of ICA vascularize?
deep brain white and grey matter regions
the circle of Willis is formed by
the proximal portion of the cerebral arteries and the communicating arteries. Located at the ventral inferior side of the brain
the anterior communicating artery in the circle of willis allow communication between
the anterior cerebral arteries
the posterior communicating arteries in the circle of Willis allow communication between
the middle and posterior cerebral artery (on both sides)