biophysiscs Flashcards
rate of blood flow to each tissue is controlled by….
tissue need. specifically by arterioles, Central nervous control, hormone control
CO is controlled by…
mainly sum of local tissue flows. specifically venous return, automatic response, central nervous control
arterial pressure reg. is generally independent of ..
local BF control or CO control
arterial pressure is controlled by
sensor feedback, kidneys
if BP falls feedback systems will
increase contractility, constrict large veins (transfer blood to arteries), stimulate constriction of arterioles (hold in artery), stimulate renal controlled change in BV
shear stress equation
(4nQ)/(pi r^3)
reynolds number equation
(vdp)/n velocity=cm/sec diameter=cm p=g/cm^3
turbulence occurs at side branches
at 200-400
straight line turbulence occurs at
2000
poiseuilles law
(pi delta p r^4)/(8nl)
blood viscosity vs water
3 times as viscous
trans cap pressures arterial
plasma colloid 28, cap pressure 30 (10 in veins), neg interstitial- 3, interstitial colloid 8 net= 13 out veins= 7i n
pulmonary trans cap pressures
plasma colloid 28, cap pressure 7, neg interstitial- 8, interstitial colloid 14 net out=1
lymphatic flow returned to circulatory system daily
2.5 liters
peripheral veins
veins out of thorax
central veins
veins in thorax. lowest pressure in vascular system. determine ventricular fillings if no lung problems
aorta: diameter, wall thickness, number, total CSA
2.5cm, 2mm , 1, 4.5 cm^2
arteries: diameter, wall thickness, number, total CSA
.4 cm, 1 mm, 160 , 20 cm^2
arterioles: diameter, wall thickness, number, total CSA
30 um ,20 um ,5 x 10^7, 400 cm^2
capillaries: diameter, wall thickness, number, total CSA
5 um, 1um, 10^10, 4500 cm^2
venules : diameter, wall thickness, number, total CSA
70 um, 7um, 10^8, 4000 cm ^2
veins: diameter, wall thickness, number, total CSA
.5cm, 5mm , 200, 40cm^2
vena cavae: diameter, wall thickness, number, total CSA
3cm, 1.5mm, 2, 18cm^2
BV distribution
pulm. circ. 9% heart 7% systemic circ. 84%. arteries 13%, arterioles and caps. 7%, veins venules and sinuses 64%
flow velocity arteries vs caps
500 mm/s vs .5mm/s
mean blood pressure in caps
20-25 mmHg
mean blood pressure in arteries
100 mmHg
arterial cap pressure
30
pulmonary cap
7 mmhG
central veins
0 mmHg
MAP formula
((PS-PD)/3) +PD or CO x TPR if CVP is 0