human phys 15.2

blood flow

volume of blood flowing through vessel, organ, or entire circulation in given period

depends on pressure gradient, resistance

blood flow

∆P/R

Blood flow equation

total peripheral resistance

the resistance of the entire cardiovascular system

opposition to blood flow, TPR

resistance

nL/r^4

resistance equation

viscosity and vessel length proportional, radius is inversely because of friction

3 factors vs resistance

laminar blood flow

type of blood flow not resulting in audible sound; defined by streamline flow or flow in parallel layers without turbulence

turbulent blood flow

type of blood flow resulting in audible sound; defined by chaotic flow due to variations of pressure and velocity

blood moves in layers, one closest to wall flows slowest bc of resistance

laminar blood flow

abnormal flow through constricted areas, greater resistance than laminar, detectable sounds

turbulent blood flows

blood pressure

the pressure that is exerted by the blood against the walls of blood vessels

systolic blood pressure

Blood pressure in the arteries during contraction of the ventricles.

created by systolic phase of heart, highest measured pressure

systolic BP

diastolic blood pressure

the pressure in the arteries when the left ventricle is refilling

created by diastolic phase, lowest measured pressure

diastolic BP

pulse pressure

difference between systolic and diastolic pressure

Korotkoff sounds

series of sounds that correspond to changes in blood flow through an artery as pressure is released

mean arterial pressure

pressure forcing blood into tissues, averaged over cardiac cycle

average BP in arteries, DP+1/3PP

MAP

as you move away from heart, MAP decreases

location vs MAP

cardiac output x TRP

MAP is also determined by

heart rate x stroke volume

cardiac output =

hermorrhage

the loss of a large amount of blood in a short time

anything that increases blood volume increases pressure

blood volume vs pressure

vascular compliance

Tendency for blood vessel volume to increase as blood pressure increases

transmural pressure

pressure difference exerted on the two sides of a wall

veins, thin walls that are easily stretched

high vascular compliance

arteries, thick walls

low compliance

velocity is inversely proportional to cross sectional area

vlocity vs area

slowest in capillaries, largest total cross sectional area, highest in aorta

where is velocity slowest/higest

circulation time

time it takes a drop of blood to travel from right atrium back to right atrium

venous return

The amount of blood returned to the heart by the veins

volume of blood flowing back to heart through veins, determined by venous pressure gradient, venous valves, pump

venous return