Lecture 13 (3/12)

Question 1

Watershed Area

Answer 1

Areas of overlapping arteries in the brain

Question 2

Safety Systems

Answer 2

Anastomosis

Blood-brain-barrier

Question 3

Anastomosis

Answer 3

A functional adaptation that enables vital organs to be supplied with blood when an artery is blocked

Dependent on the connection of the blood vessels or arteries that make up the circle of Willis

A safety valve that is build into the system to prevent a catastrophe if an artery is blocked

Only works if the blockage occurs below the circle of Willis

Question 4

Blood-Brain-Barrier

Answer 4

The blood and CSF in the brain have a complex system by means of which the brain tissues don’t draw easily on them

Aka: Prevents toxins from being absorbed into the brain

Question 5

Arterial Occlusions

Answer 5

The amount of tissue affected by an arterial occlusion depends on the location of the occlusion and the type of artery

If the occlusion occurs in the trunk of an artery more tissues will be affected than if the occlusion occurs on the branch

Question 6

Occlusion to the Anterior Cerebral Artery

Answer 6

ACA supplies the medial portion of the brain

Damage here involves mainly the leg and foot

Damage here causes:
Contralateral hemiparesis
Hemisensory loss
Tactile Agnosia

Question 7

Occlusion to the Middle Cerebral Artery

Answer 7

MCA supplies the lateral portion of the brain

Damage here involves the arms and face

Damage here causes:
Hemiparesis (precentral gyrus)
Hemisensory loss (postcentral gyrus)
Aphasia
-occurs if the left hemisphere is affected
Contralateral homonymous hemianopia
-blindness in the same half of the visual field in both eyes
Anosagnosia
-occurs if the right hemisphere is affected typically
-the patient is in denial of the problem

Question 8

Occlusion to the Posterior Cerebral Artery

Answer 8

PCA supplies the posterior portion of the brain

Damage here causes:
Contralateral homonymous hemianopia
Visual agnosia
-perceptual deficit
Memory impairment
-due to involvement of the temporal lobe

Question 9

Occlusion to the Internal Carotid Artery

Answer 9

Damage here caused if BELOW the circle of Willis

May have partial or complete loss of sight

• Depends on the degree of collateral anastomosis
• -depends on the age of the patient
• -cholesterol levels
• -smoking