Special Circulations Flashcards
where does the coronary sinus drain to
right atrium
name some special adaptions of the coronary circulation
high capillary density
high basal blood flow
high oxygen extraction
factors causing dilatation of coronary arteries
dec PO2 inc PCO2 dec pH inc K adenosine
effect of stimulation of coronary arteries by sympathetic vasoconstrictor nerves
vasoconstrictor nerve are overridden by metabolic hyperaemia - resulting in coronary vasodilatation. circulating adrenaline activates B2 ADR.
when does left coronary blood flow mainly occur
during diastole
where is grey matter and what is in it
cerebral cortex of brain
cell bodies
where is white matter and what is found in it
inner area of brain
axons which are myelinated (white appearance)
why does hyperventilation lead to fainting
dec PCO2 causes cerebral vasoconstriction
CPP =
MAP - ICP
what increases ICP
head injury or brain tumour etc
what type of junctions are there in BBB
tight
what support cells surround the brain capillaries
astrocytes
what substances can pass through the BBB
O2
CO2
glucose
how does the pulmonary circulation protect from oedema
adsorptive forces > filtration forces
effect of hypoxia on pulmonary arterioles
constrict - dives blood from poorly ventilated areas of the lung
