CSF circulation

Question 1

Cerebral Capillaries

Answer 1

1_ They represent BBB
2_ Tight junction except: capillaries of choroid plexus.
3_Limited diffusion & vascular transport

Question 2

factors affect CeBF:

Answer 2

1) Cerebral perfusion pressure: (CPP).

2) Cerebral vascular resistance: (CVR).

Question 3

difference between ABP at head level & pr. In internal Jugular vein.

Answer 3

Cerebral perfusion pressure: (CPP)

Question 4

Autoregulation

Answer 4

the ability of brain to maintain CeBF constant inspite of changes in MAP between 50-150 mmHg.

Question 5

Theories of Autoregulation

Answer 5

1) Tissue pressure mechanism
2) Myogenic mechanism
3) Metabolic mechanism

Question 6

Monro-Kellie doctrine and Role of intracranial pressure

Answer 6

According to “Monro-Kellie doctrine”: ↑ intractranial pressure →↓ CeBF because the brain is enclosed by the hard skull & any ↑ in any component →↓ in other components.

Question 7

Cushing reflex

Answer 7

↑ intracranial pressure (e.q brain tumor) compression of 1 cerebral blood vessels → brain ischemia with ↑ CO2, 102&t H+→ stimulation of VMC → V.C. of systemic arterioles → ↑ Peripheral Resistance marked in blood pressure, associated with bradycardia (↓ H.R).