Brain And Blood Supply

Question 1

The body supplies blood to the brain via the internal carotid and vertebral arteries. These vessels come together to form a ring called the circle of Willis. The function of the circle of Willis is to provide a shunt system should any of the vessels become damaged.

Arising from the circle are the three main vessels that supply the brain with blood;

Answer 1

cerebral artery, and the posterior cerebral artery.

Question 2

Anterior cerebral artery (ACA) occlusion

Answer 2

Occlusion of the anterior cerebral artery may result in the following defects

Hemiparesis of the contralateral foot and leg (more severely than the arm)
Sensory loss of the contralateral foot and leg
Motor dysphasia

Question 3

Middle cerebral artery (MCA) occlusion

Answer 3

Occlusion of the middle cerebral artery may result in the following defects

Hemiparesis of the contralateral face and limbs
Sensory loss of contralateral face and limbs
Dysphasia (when dominant hemisphere affected)
Contralateral neglect
Homonymous hemianopia or quadrantanopia
Dorsolateral prefrontal dysfunction

Question 4

Posterior cerebral artery (PCA) occlusion

Answer 4

Occlusion of the posterior cerebral artery may result in the following defects

Alexia without agraphia (left PCA)
Contralateral loss of pain and temperature sensation
Contralateral hemianopia
Prosopagnosia
Ipsilateral cranial nerve defects (V, VIII, IX, X, & XI)
Horner’s syndrome
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