S2W4 L2- Circulatory Physiology- Special Circulations- Prof Derek Steele Flashcards
total blood flow average (CO)
5.8 L/min
why do we have coronary arteries and veins
heart is too large to be oxygenated by just blood passing through myocardium
where do right and left coronary arteries supply
walls of myocardium
where does most venous blood drain via
coronary sinus
why do the myocardial capillaries have very small max diffusion distance
high density
small diameter of myocytes
why are coronary arteries compressed during systole
3D structure
what does obstruction in coronary arteries cause
ischemia of tissue downstream, leads to myocardial infraction
what does gradual obstruction of coronary arteries cause
development of collateral vessels
why are pulmonary capillaries more susceptible to stress failure than systemic
they are not surrounded by supporting tissues
why is blood flow unevenly sitribted in lungs of an upright subject
pulmonary pressure higher at base than apex
why is there a lower resitance and higher blood flow at base of lung
pressure higher at base, high pressure distends vessels of microcirculation
what happens to the vessels of the apex during systole
collapse
what becomes the primary determinant of systemic vascular resistance during exercise
skeletal muscle resistance
which type of muscle has greater capillary density
slow twitch (red) greater than fast twitch (white)
active hyperaemia
increase in blood flow associated with an increase in metabolism
