Midterm 1 - Blood Vessels and Blood Pressure Flashcards
important factors of blood pressure in blood vessels
diameter
elasticity
contractility
what blood vessel is the target to regulate pressure
arteriole
how does an edema occur
no venous return, blood sits in capillaries and fluid builds
flow
volume of fluid transported per time unit
what is flow between 2 points dependent on
pressure difference between the 2 points and resistance to fluid
how to calculate flow (Q)
pressure difference/resistance
is pressure higher in arteries or veins
arteries
what are arterioles
the “bottlenecks” of the circulation
why are arterioles the main site of pressure/flow regulation
they have the most smooth muscle
what does initial pressure result from
heart contraction
does pressure progressively increase or decrease
decrease
what does resistance depend on
length of vessel
radius of vessel
blood viscosity
what is constant in an individual
the length of vessel
what is the most important factor for resistance
radius of vessel
why is radius so important for resistance
resistance decreases by the 4th power of the radius: if the radius increased 2 times, resistance decreases 16 times
what does viscosity of blood vary with
cells and proteins amount
what occurs during ventricular contraction when aortic valves open
rapid flow of blood
increased arterial pressure
some pressure is absorbed by aorta elasticity
what does aorta elasticity do with pressure
temporarily stores energy like a rubber plastic
what occurs during diastole when the aortic valve closes
no blood flowing from ventricle
stored energy is released
allows blood flow to continue in vessels
gradual decrease in arterial pressure
what are compliant
arteries
what does the elasticity and large diameter of arteries supply
low resistance
high flow
what does the recoil of wall of artery limit
the drop in pressure after systole
how can a difference in arterial blood pressure be observed
between systole pressure and diastole pressure
pulse pressure
difference between systolic and diastolic pressure
what occurs to the mean blood pressure during rest
MBP closer to diastolic pressure (diastolic lasts longer than systole)
what occurs to the mean blood pressure during exercise
MBP closer to systolic pressure (heart rate increased = diastole shortened)
what is pulse pressure the measure of
measure of pressure on artery wall during systole
factors influencing arterial pressure
elasticity of artery
cardiac output
respiration
resistance to blood flow
blood volume
what is the main factor influencing arterial pressure
resistance to blood flow
what influence does aging have with elasticity of artery
low elasticity = high pressure
what influence does more blood from systole have on pressure
more blood = increased pressure
what occurs during inspiration
low pressure in thoracic cavity, high pressure in abdominal cavity
what does the pressure occurring during inspiration promote
venous return
what does total peripheral resistance depend on
vasoconstriction of arterioles. increase in TPR = increase pressure