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Self-Assessment Questions for Year 1 CVS 2004-05
Series 1 covering
Mechanical Properties of the heart
Blood Vessels and Blood Flow
Which of the following statements are true and which are false
1. Starling’s Law of the heart states that increased diastolic fibre length increases
ventricular contraction (T)
2. The Frank-Starling relationship arises through changes to the number of
myofilament cross bridges that interact (T)
3. The work performed by the left ventricle is substantially greater than that performed
by the right ventricle because in the left ventricle the stroke volume is greater (F)
4. The Frank-Starling relationship arises through changes to the Ca sensitivity of the
myofilaments (T)
5. The work performed by the left ventricle is substantially greater than that performed
by the right ventricle because in the left ventricle the afterload is greater (T)
6. In the cardiac cycle isovolumic contraction follows atrial systole (T)
7. The 1st heart sound is due to closure of the aortic and pulmonary valves at the start
of ventricular systole (F) (Mitral valve closing)
8. In the cardiac cycle isovolumic contraction follows isovolumic relaxation (F) (Rapid
filling follows isovolumic relaxation)
9. Blood pressure depends on cardiac output and vascular resistance (T) (BP = CO x
TPR)
10. Mean blood pressure is commonly calculated as diastolic pressure + 1/2 pulse
pressure (F) (diastolic + 1/3 pulse pressure)
11. The capillary segment of the circulation presents greatest resistance to flow (F)
(Arterial segment)
12. The majority of blood volume is located in the arterial side of the circulation (F)
(venous)
13. The capillary segment of the circulation presents the largest cross sectional area in
the circulation (T)
14. Resistance to flow is higher in the pulmonary than the systemic circulation (F)
(systemic arteries & arterioles)
15. In laminar developed flow, resistance is proportional to the cube of the tube radius
(r3) (F) (Rviscosity x length / r4)
16. According to Laplace's law, wall tension (T) depends on pressure (P), vessel
radius (R) and flow (F) (T = P.R.F) (F) (Wall tension not dependent on flow; T =
PxR)
17. Venous return is assisted by the action of skeletal muscle pumps (T)
18. Extracellular calcium plays a major role in the excitation-contraction coupling of
cardiac but not skeletal muscle. (T)
19. An in vivo correlate of preload is end diastolic pressure (T)
20. Normal end diastolic volume ≈ 130 ml (T)
21. Relaxation of cardiac muscle occurs because calcium is removed from the
cytoplasm and pumped into the sarcoplasmic reticulum by the Na/Ca exchange
protein. (F) (SERCA pumps Ca into the SR)
22. Cardiac muscle is more resistant to stretch than skeletal muscle (T)
23. Cardiac muscle works on the ascending and descending limbs of the length-tension
relationship (F)
24. The stimulus for calcium release from the sarcoplasmic reticulum is the same in
both cardiac and skeletal muscles (F).
25. The ejection fraction = stroke volume (F) (EF = SV / EDV)