Meningeal Arteries

Question 1

describe the cerebral arteries

Answer 1

• vertebral and internal carotid arteries anastomose at the basal diencephalon (by forming the Circle of Willis)
• these major arteries supply the basilar, cerebellar and cerebral arteries

Question 2

Answer 2

Question 4

_______ arteries feed the middle and anterior cerebral arteries

Answer 4

internal carotid arteries feed the middle and anterior cerebral arteries

Question 5

middle arteries emit the ______ arteries that supply the _____ and ______

Answer 5

middle arteries emit the lenticulostriate arteries that supply the internal capsule and basal ganglia

Question 6

the _____ _____ artery connects the anterior cerebral arteries

Answer 6

the anterior communicating artery connects the anterior cerebral arteries

Question 7

Answer 7

Question 8

Answer 8

Question 9

describe the posterior cerebral arteries

Answer 9

• posterior cerebral arteries arise from the basilar artery, anastomosing with the internal carotid system via the posterior communicating arteries

Question 12

descrbie an epidural hemorrhage

Answer 12

• epidural hemorrhages commonly reflect the traumatically induced rupture of meningeal arterties (e.g. middle meningeal artery) with a fractured bone cutting the vessel
• during the episode, blood forces the stiff periosteal dura to separate from the skull, yielding a characteristic biconvex mass adjacent to the fracture
• dangers peak within hours of arterial involvement

Question 13

describe origin of lenticulostriate arteries and what they supply

Answer 13

• lenticulostriate arteries branch from the middle cerebral artery and supply the internal capsule and basal ganglia
  
  • internal capsule = connects cortical and subcortical sites aka projection

Question 14

describe a subdural hemorrhage

Answer 14

• subdural hemorrhages reflect trauma-induced ruptures of the delivate veins that traverse the meningeal layer of the dura from the subarachnoid space
• because the pressure in the venous system is much lower than in the arterial system, crescent-shaped subdural masses of blood develop slowly before manifestation (hours to weeks)

Question 15

describe a subarachnoid hemorrhage

Answer 15

• many arteries reside between the arachnoid and pia mater (surrounded by CSF within the subarachnoid space)
• these vessels may rupture with trauma or spontaneously (in cases of aneurysm)
  
  • the leaking blood assumes a tree-like appearance while following the sulci

Question 16

describe an intracerebral hemorrhage

Answer 16

• intracerebral hemorrhages reflect rupture of intraparenchymal branches of subarachnoid arteries such as the lenticulostriate arteries which branch from the middle cerebral artery, supplying the internal capsule and basal ganglia

Question 18

as opposed to the arachnoid layer which is _____, the pia mater is highly _____

Answer 18

as opposed to the arachnoid layer which is avascular, the pia mater is highly vascular

Question 19

the _____ ______ artery runs medially and anterior the optic chiasm

Answer 19

the anterior cerebral artery runs medially and anterior the optic chiasm

Question 20

describe origin of striate arteries and what they supply

Answer 20

• striate arteries (early branches of the anterior cerebral artery) supply the basal ganglia and anterior limb of the internal capsule

Question 21

describe what the anterior cerebral arteries supply

Answer 21

• major branches of the anterior cerebral arteries pass to the medial aspect of the frontal and parietal lobes, anterior perforated substance, septum pellucidum and corpus callosum (feeding all but the most posterior zones of this commissure)

Question 22

describe what middle cerebral arteries supply

Answer 22

• the middle cerebral artery extends laterally in lateral fissures over the insula, sending branches to the lateral aspect of frontal, temporal and parietal lobes
• during its early course, the middle cerebral a. emits the lenticulostriate arteries, which supply the basal ganglia and internal capsule
  
  • these arteries are vulnerable to rupture and are a major source of intracerebral (periventricular) hemorrhage

Question 23

describe the origin of posterior cerebral arteries and what they supply

Answer 23

• posterior cerebral arteries are the terminal branches of the basilar artery
• they travel laterally and dorsally around the midbrain to reach the thalamus and third ventricle
• cerebral branches supply medial temporal, occipital and parietal structures

Question 24

occlusion of the ____ ____ a. often yields language deficits, as this artery normall supplis cortical regions subserving verbal and literal elements of speech

Answer 24

occlusion of the middle cerebral artery often yields language deficits, as this artery normall supplis cortical regions subserving verbal and literal elements of speech

Question 25

describe autoregulation of blood flow in the CNS

Answer 25

• brain arterioles constrict when system blood pressure is raised and dilate when it is lowered so that the cerebral blood flow is constant over an arterial pressure range of 60-150 mmHg
• mediates through Arg>NO>cGMP pathway