A workshop

Question 1

Flow chart of increase in SBP & DBP (starting from kidneys)

Answer 1

• Kidneys → GFR → Na/H2O balance → ECF vol → Plasma vol → blood vol → venous pressure/vol → ↑VR → ↑ventricular filing (EDV) → ↑SV → ↑CO → ↑MAP → ↑SBP/DBP

Question 2

Determinant of pulse pressure

Answer 2

• SV
• Arteriole compliance (also affects velocity of blood)
• Reflected wave

Question 3

What is the ejection fraction normally?

Answer 3

• Only ~1/2 of EDV ejected per heart beat

Question 4

Features of a reflected wave

Answer 4

• Degree of reflection depends on TPR (↑TPR → ↑reflected wave)
• Meets primary wave during diastole
• BF in coronary A is during diastole as well

Question 5

What occurs to the reflected waves as a result of age

Answer 5

• ↑age → ↑stiffness of vessls → ↑velocity → reflected wave & primary wave meet during systole

Question 6

Consequence of age on reflected waves

Answer 6

• Results in ↑SBP & ↓DBP → ↑work of heart (needs to pump against higher pressure) → ↑need of O2 supply → Need to ↑blood in coronary A BUT DBP is low (& BF in coronary A is during diastole)