W6 Intro to Blood Pressure Regulation Flashcards
what is cardiac output? how is it calculated?
blood flow in volume / time - cardiac output = heart rate (beats per minute) x stroke volume (volume of blood per beat)
what is systole?
ventricular contraction
what is diastole?
ventricular filling (relaxation)
what is end systolic volume (ESV)?
volume of the ventricle at the end of contraction
what is end diastolic volume (EDV)?
volume of ventricle just before contraction/end of filling
how do you calculate stroke volume?
SV = EDV - ESV
what is mean blood pressure controlled by?
by changing peripheral resistance and/or cardiac output as pressure = CO x TPR
cardiac output is controlled by S and PS nerves, what does this effect?
heart rate and force of contraction
total peripheral resistance is controlled by nervous and chemical means which effects what?
constriction and dilation of arterioles and venules and elasticty
what is arterial blood pressure measured in?
mm Hg (millimeters of mercury)
what is systolic blood pressure?
the maximum arterial blood pressure during heart contraction
what is diastolic blood pressure?
minimum arterial blood pressure during heart relaxation
what is mean arterial pressure?
the mean pressure over the entire cardiac cycle (usually not equal to the mean of SBP and DBP as not the same duration)
is heart rate higher in smaller or larger animals?
hr is higher in smaller animals due to small vessels and higher resistances
what is the average systolic pressure of domestic animals, rats/mice, birds and giraffe?
125-145
100-120
175-250
280-350
what is the average diastolic pressure of domestic animals, rats/mice, birds and giraffe?
80-95
70-80
150-170
200-300
what is the average mean pressure (mmHG) of domestic animals, rats/mice, birds and giraffe?
100-110
85-100
160-200
300
why is it important to maintain pressure within a range?
ensures adequate perfusion of vital organs
what do baroreceptors do?
used for short term regulation of blood pressure - they are in the arterial wall and increase their firing rate in response to increased stretch (due to increased pressure)
where are the most important baroreceptors found?
in the carotid artery (in carotid bodies) and the aortic arch (in aortic bodies)
what is the net result of baroreceptors on blood pressure?
vasodilation, decreased heart rate, decreased contractility which restore arterial pressure to normal
what do the carotid sinus baroreceptors detect?
changes in pressure to the brain
what do the aortic arch baroreceptors detect?
changes in pressure to the body
what are peripheral and central chemoreceptors stimulated by?
low arterial O2 and high arterial CO2 and low arterial pH
