Blood Vessels and Blood Pressure Flashcards
What are blood vessels?
conduits to move blood to peripheral tissue to bring nutrients and remove waste
what is the general path of a portal system in the circulatory system? What are two portal systems found in the body?
blood flows from arteriole to the capillary bed, to the venule then to a second capillary bed then back to the venous system
hepatic, hypophyseal
What are 3 components of microcirculation?
arterioles
capillaries
venules
What is the equation for blood flow rate?
F = deltaP/R F = flow deltaP = pressure gradient R = resistance
why is a pressure gradient important in flow rate? how is the cardiac pump involved?
it is the main driving force for flow
cardiac pump = energy source
Is mean arterial pressure (MAP) usually higher or lower than the pressure in arterioles right before it reaches capillaries? Why?
higher
absolute pressure downstream from the point of high resistance usually decreases
what is flow?
measure of volume per unit of time
what is velocity?
measure of linear distance per unit of time
what slows blood flow rate?
friction - greater surface area in contact with blood will have greater resistance
what is the fourth power of vessel radius rule?
increase the radius 2x leads to a 16-fold increase in flow rate and a 16-fold decrease in resistance
what is poiseuille’s law?
describes the factors that affect flow rate flow rate = (pi)(deltaP)(r^2)/8nL n = viscosity L = vessel length r = vessel radius (important)
how does atherosclerosis affect vessel radius and flow rate?
decrease radius due to plaque, leading to decreased flow rate
how does hypertension affect vessel radius and flow rate?
decrease radius do to impaired vascular function, leading to decreased flow rate
what is systolic pressure?
arterial pressure during contraction (120mmHg)
what is diastolic pressure?
arterial pressure during relaxation (80mmHg)
what is a blood pressure reading?
systolic/diastolic
120/80 (pressure difference = 40mmHg)
what is pulse pressure?
what you can feel on the skin due to shallow arteries
what is mean arterial pressure?
average pressure driving the blood forward into tissues
how do you calculate MAP? what is the typical MAP when BP is 120/80
MAP = ((S-D)/3) + D or pp/3 + D pp = pulse pressure MAP = 93mmHg
What are components of sphygmomanometry?
arm cuff
stethoscope
pressure-recording device
what occurs when cuff pressure is greater than 120mmHg?
no blood flow
no sound heard
what occurs when cuff pressure is between 120mmHg and 80mmHg?
blood flow is turbulent whenever pressure exceeds cuff pressure
intermittent sounds heard as BP fluctuates throughout cardiac cycle
what occurs when cuff pressure is below 80mmHg?
smooth blood flow
no sound heard
what are korotkoff sounds?
sounds heard in stethoscope from blood flowing
what is considered high normal blood pressure?
sys: 130-139
dia: 85-90
what is considered hypertension?
sys > 140
dia > 90
what is considered stage 1 hypertension?
sys: 140-159
dia: 90-99
what is considered stage 2 hypertension?
sys > 160
dia > 100
what is considered hypertension in diabetic/kidney disease patients?
sys >130
dia >80
what are 3 drugs that are often prescribed for hypertension?
lisinopril
amlodipine besylate
hydrochlorothiazide
