bp Flashcards
define blood pressure
the pressure exerted by blood on the wall of a blood vessel
what is blood pressure measured in
mmHg
define systolic blood pressure
is the highest pressure and is measured when the left ventricle is contracting and expelling blood into aorta
define diastolic blood pressure
the lowest blood pressure measured when left ventricle is relaxing and blood is flowing into peripheral blood vessels
what is the device called that measure bp
sphygmomanometer
what does PP stand for
Pulse Pressure
define pulse pressure
the difference between systolic and diastolic pressure
what is a text book pp
120/80=40mmHg
what is mean arteriole pressure
pressure that propels the blood through tissue
what does map stand for
mean arteriole pressure
what is map equivalent too
diastolic bp- 1/3 pp = MAP
how many factors can affect blood pressure and explain 3
6
cardiac output- more blood your heart pumps the higher the pressure
peripheral resistance- vasoconstriction and increased length of bv means greater bp, opposite for vasodilation.
blood volume- increased vol=increased press
viscosity-thicker means harder to pump=increase
vasoconstriction/dilation
which receptor monitors bp
baro-receptors
explain the homeostatic loop for low blood pressure detection
- arteriole pressure falls, 2. baroreceptors inhibited, 3. impulse from baroreceptors stimulate cardioacceleratory centre and vasomotor centre, 4. increase HR, contractility and cardiac output, 5. increased bp to normal level
what is Marleys law
there is an inverse relationship between bp and hr
explain Marleys law
if bp too high, hr will decrease
if bp too low, hr will increase
what does SV stand for
stroke volume
define stroke volume.
the amount of blood ejected from the ventricle during one contraction
the equation for sv
sv= edv-esv
stroke vol= end diastolic vol- end systolic vol
what does preload mean
the degree to which ventricular muscle is stretched just before contraction
define afterload
the pressure that ventricles must overcome to push blood through semi-lunar valves
what is the pressure exerted by the left and right ventricles retrospectively
left exerts= 80mmHg as pushed round body
right exerts= 8mmHg as pushed to lungs
name 2 factors that enhance cardiac output
exercise , decreased BP
which receptor detects increased muscle activity
proprioceptors
