ANA 301 Blood Supply To The Brain

Question 1

Facts about the blood supply to the brain

Answer 1

If blood supply stops - 10 sec - Unconscious
• If it continue to cease - irreversible damage
• starts at 4 min - completes in 10 min
• Brain consists of 2% of total body but
• Receives 20% cardiac output
• 20% total 02

Question 2

The brain is supplied by 2 sets of arteries

Answer 2

A pair of vertebral arteries
A pair of internal carotid arteries

Question 3

Circle of Willis

Answer 3

Anteriorly: Anterior communicating & anterior cerebral arteries
Posteriorly: Basilar artery dividing into 2 posterior cerebral arteries
Laterally on either side: Posterior communicating artery connecting internal carotid with posterior cerebral artery

Question 4

Circle of Wiliis lies around where?

Answer 4

Interpenduncular fossa

Question 5

Functional significance of circle of willis

Answer 5

• Equalizes blood flow to different parts of the brain
• Little interchange of blood across the right and left half due to equality of blood pressure
• In case of occlusion, the circle of Willis acts as principal collateral channel

Question 6

Branches of the cranial parts of the vertebral artery

Answer 6

1. Anterior spinal artery
2. Posterior spinal
3. ;osterior inferior cerebellar (largest branch)
4. Meningeal arteries: supply the dura mater of posterior cranial fossa
5. Medullary arteries: supplies medulla oblongata

Question 7

Branches of the basilar artery

Answer 7

1. Pontine arteries
2. Anterior inferior cerebellar artery
3. Labyrinthine artery
4. Superior cerebellar aretry
5. Posterior cerebral artery
   anterior temporal
   posterior temporal
   parieto-occipital
   calcarine artery

Question 8

Branches of Internal Carotid Artery

Answer 8

1. Ophthalmic artery
2. Posterior communicating
3. Anterior Choroidal: supplies choroid plexus of the interior horn of Lateral Ventricle (artery of cerebral thrombosis)
4. Anterior cerebral artery
5. Middle cerebral artery
6. Hypophyseal arteries

Question 9

Branching Pattern of cerebral arteries

Answer 9

Cortical branches
Central branches (perforating arteries)
Choroidal arteries

Question 10

Cortical branches

Answer 10

1. supplies outer portion of the cerebrum
2. derived from the anterior, middle and posterior cerebral arteries
3. Ramify in the pia mater & form freely anastomosing superficial plexuses