Blood Pressure and Behaviour Flashcards
What is pulse pressure?
[systolic] - [diastolic]
What is Mean Arterial Pressure (MAP)?
average pressure in the arterial system over systole and diastole.
MAP =
CO x VR
VR is vascular resistance
CO =
HR x SV
SV is stroke volume
If you have intra-arterial blood pressure measurements, then MAP =
= (diastolic) + (pulse pressure)/3
What can happen to the aorta as you get older? How does this affect BP?
It loses elasticity - meaning BP can vary more wildly since the aorta isn’t stretching to compensate.
Things that reduce _________ will prolong orthostatic hypotension.
venous return
What factors increasing venous return are there when you’re up and not there when you’re lying down?
skeletal muscle pumps, compression of veins
What is a variable factor in peripheral resistance to CO?
arteriolar diameter
what effect does haematocrit have on blood viscocity?
increases friction (i.e. viscocity) hence BP. recall the spleen can vary this in other mammals more effectively that in humans.
Just as a prompt, what are five factors contributing to peripheral resistance?
viscosity (haematocrit) carotid baroreceptor reflex vasomotor changes (arteriole dilation) elasticity of blood vessels total blood volume
What physiological process has the greatest influence on BP on a moment-to-moment basis?
The baroreceptor reflex.
Let’s get down modifiable risk factors for BP
fat, salt, alcohol, smoking, vegetables diabetes, hormone medications, electrolyte intake (Ca2+, K+) physical activity, oral contraceptives stress
Five examples of secondary hypertension
aortic coarctation pheochromocytoma (adrenal cortex tumour - excess adrenaline) Other adrenal cortical problems sleep apnoea kidney disease
