blood pressure and haemodynamics 3

Question 1

• The transmural pressure is the pressure that either — or — the —
• It is the — in pressure — the wall: PTM = –
• If the pressure outside (Po) exceeds the pressure inside (Pi) then the
  vessel will —
  – inflation of a blood pressure cuff to supra-systolic pressure or tourniquet
• The transmural pressure is related to the wall — and the — – via the Law of LaPlace
• the law of LaPlace:
• Transmural pressure is — divided by — – PTM = —
• So wall tension increases with —

Answer 1

distends or collapses
difference
across
pi- po
collaps
tension and radius
wall tension/ radius
T÷r or rearranged to T=PTM XR
radius

Question 2

• Wall tension is how “—” the vessel wall needs to be
• For vessels with a small radius, — wall tension is required to balance out the distending pressure
  – so even though they are thin walled, capillaries are protected from rupture due to their – size
• For vessels with a larger radius, — wall tension is required to balance the distending pressure
  – this is why a dilated aneurysm is more likely to —
  – this is also more likely in the — than — due to the – pressure in the venous system
  – the thin walls of the veins however mean they are more likely to —

Answer 2

thick
less
small
more
rapture
aorta than vena cave
lower
collapse

Question 3

• Veins are much more — than arteries (approx. x8) – really just their capacity to — and —
• Compliance (C) is the change in — for a given change in — and so relates to a —
  –C=ΔV÷ΔP so can be rearranged to ΔV=CxΔP
• Since veins have – volume as well as — distensibility, they are approximately — more — than arteries
  – high compliance means a greater change in— per unit change in pressure
  – this is how veins perform — function and act as a — for blood

Answer 3

distensible
expand and swell
volume
pressure
distensibility
large
greater
20x
compliant
arteries
volume
capacitance and reservoir

Question 4

• Systolic pressure (the pressure during systole) is dependent on the —
  – increasing — will increase systolic pressure
• Diastolic pressure (the pressure during diastole) is dependent on the – and so reflects—
  – increasing the — will increase the diastolic pressure
• — contributes most to the mean arterial pressure
• The— is the pressure across a cardiac cycle
• and the heart spends longer in— (–)
  compared to — (–)
  Mean arterial pressure = DBP + 1/3 (SBP – DBP)

Answer 4

cardiac output
cardiac output
vasculature
total peripheral resistance
total peripheral resistance
diastolic pressure
MAP
diastole
3/5
systole
2/5

Question 5

• Blood pressure falls during — and undergoes the morning surge after waking
• It starts to fall in the – but is susceptible to various other factors – e.g.exercise,coffee/stimulants
  how does expanding the blood volume increase blood pressure:
• It is a closed system, so any expansion has to ultimately return to the –
• The increased venous return will stretch the — (Starling’s Law) and so increase the –
• CO=HRxSV and MAP=COxTPR

Answer 5

sleep
afternoon
heart
myocardium
stroke volume

Question 6

• Long-term regulation of blood pressure is via – and — - mediated Na retention – how does this lead to volume expansion? ( This is the reason why high salt intake is related to hypertension)
• Osmolality (FFP1 !)
• Activation of RAS and aldosterone leads to — and a subsequent — in plasma osmolality – think of it akin to dehydration
• The homeostatic response to raised osmolality is the release of –
  – osmolality is regulated not by the loss of solute but by diluting it in more solvent
• So – drives na+ retention , ADH water retention and between them plasma volume is expanded

Answer 6

ras and aldesterone
retention of na+
increase
adh
ras

Question 7

• With reference to Poiseuille’s Law, how does arterial constriction and dilatation regulate the regional distribution of blood flow?
• Blood flows down the path of — resistance
• Your cardiovascular system is not arranged in series like a central
  heating system but instead is arranged in —
• This means changes in resistance by constriction or dilation of certain vascular beds will lead to a — of blood flow

Answer 7

least
parrall
redistribution

Question 8

• Why does a bruit suggest the presence of an atherosclerotic plaque?
• Blood flow is — and — and should not be —
• The presence of a bruit does not suggest a — per se but it does suggest — and a — would cause this

Answer 8

laminar
silent
audible
plaque
turbulence
plaque