Cerebral Circulation

Question 1

What are the anterior cerebral artery and medial cerebral arteries?

Answer 1

.After ascending to the brain the internal carotid arteries split into the anterior and middle cerebral arteries.

Question 2

Blood-brain barrier

Answer 2

• Nowhere in the body is there more need for homeostasis than in the brain.
• The blood brain barrier protects the brain against fluctuations in ion concentrations.

Question 3

Internal Carotid Artery

Answer 3

• In the neck
• Enters the cranium through the carotid canal in the temporal bone
• Has a number of branches

Question 4

Internal Carotid Artery

Answer 4

• In the neck
• Enters the cranium through the carotid canal in the temporal bone
• Has a number of branches
• Supplies the brain with 80% of blood

Question 5

What does Homeostasis mean?

Answer 5

Equilibrium

Question 6

What is the brain tissue supplied by?

Answer 6

Brain tissue is supplied by two pairs of arteries: the internal carotid (ICA) and vertebral arteries (VA)

Question 7

What is the Circle of Willis?

Answer 7

It is an anastomosis (connection) between the twp internal carotid arteries and vertebral systems (the two pairs of arteries that supply the brain)

It can potentially maintain brain perfusion (delivery of blood to a capillary bed) even when one ICA becomes blocked

Question 8

What does anastomosis mean?

Answer 8

Connection

Question 9

Vertebral Arteries

Answer 9

Ascends the neck by passing through a foramen in the cervical vertebrae.

Supplies the brain with 20% of blood.

Question 10

What is the posterior cerebral artery?

Answer 10

It supplies the back of the brain.

Question 11

What do cortical branches do?

Answer 11

Cortical branches to the surface of the brain supply cortical grey matter

Question 12

What do choroidal branches do?

Answer 12

Supply the choroid plexus

Question 13

What do the central branches do?

Answer 13

Penetrates into the brain substance to supply fibre tracts and sub-cortical grey matter

Question 14

What is Cerebrovascular Disease?

Answer 14

Defined as any disease affecting an artery within the brain, or supplying blood to the brain.

Question 15

What are the types of Cerebrovascular Diseases?

Answer 15

• Atheroscierosis where plaques (fatty deposits) form leading to narrowing of the arteries
• Aneurysm (a defect or weakness in a blood vessel in the brain which can cause a ballooning of an artery)
• Stroke when there is a sudden blockage or rupture of a blood vessel within the brain, the blockage may be due to a blood clot forming in the cerebral arteries (a thrombosis) or by a fragment of material (blood clot, piece of tissue, cholesterol or other substances) travelling in the blood streak (an embolism)