Cardiovascular physiology X

1. What is the basic function of papillary muscles?

Prevent bulging of AV valves into the atria

2. What is the cause of incisura in aortic pressure curve?

The backward fow of blood after closure of the aortic valves

3. What is the volume of blood that remains (left behind) in the ventricle after its contraction?

45 mL (end systolic volume)

4. What is the degree to which the myocardium is stretched before it contracts called?

Preload

5. What is the resistance against which blood is expelled called?

After load

6. What is the diastolic pressure in the ventricle at the end of ventricular diastole (complete filling)?

5 mm Hg

7. What is the pressure in the left ventricle at the end of the period of isovolumetric contraction?

80 mm Hg

8. During isovolumetric relaxation, what is the volume of the ventricle?

45 mL

9. What is the main source of energy for cardiac muscle contraction?

Oxidative metabolism of fatty acids

10. What is the ratio of work output to total chemical energy expenditure in the heart called?

Effciency of heart

11. In the heart failure, what is the maximum efficiency the heart may decrease?

5 – 10%

12. Force of the contraction is directly proportional to the end-diastolic volume within physiological limits. What is this called?

Frank-Starling law

13. What is the alternate name of ventricular function curve?

Stroke-work output curve (Starling curves)

14. Name the ion that causes the heart to faccid dilatation when it is excess in ECF.

Potassium ions

15. Name the positive ion which produces a decrease in resting membrane potential in cardiac muscle fibre when in excess.

Potassium ions

(Physiology; UMS 2008)