Blood pressure Flashcards
Outline the differences between series and parallel blood flow
series: 2 paths in a row, flow is the same in both, the pressure is higher in the first path than the second.
parallel: branching paths, flow is split, the pressure is the same at the start and both have identical resistance.
Define stroke volume
The volume of blood pumped out of the ventricle during one beat of the heart
Define heart rate
measured in beats per min
Define cardiac output and what is the equation
The volume of blood pumped out of a ventricle per min
CO= HR*SV
What is the end-diastolic volume
the volume of blood in a ventricle at the end of diastole, associated with preload.
What is the end-systolic volume
the volume of blood remaining in a ventricle at the end of systole. SV: EDV-ESV
What is the ejection fraction
The percentage of filled ventricular volume pumped out during a heartbeat: SV/EDV
What is the effect of a smaller radius in blood vessels
it increases resistance and leads to a lower flow rate
What is the effect of exercise on blood pressure
peripheral vasodilatation: muscle/skin
vasoconstriction: splanchnic circulation (gut)
BP: systolic (increase), diastolic (decrease), HR increases
Describe how endothelial cells achieve vasodilatation
Releases nitric oxide which causes the smooth muscle to relax and leads to vasodilatation.
Outline autonomic control of BP
Baroreceptors located in the transverse aortic arch detect BP which relay the information to the medulla that acts to increase or decrease HR, PR, pressure, CO.
Outline the Frank-Starling mechanism
The stroke volume of the heart increases in response to an increase in the stretching of blood filling the heart (EDP)
define venous return
the rate of blood flowing back to the heart through the veins
define preload
The initial stretching of the cardiomyocytes during diastole, dependant on venous return
What is volume overload
Results when preload becomes too large
