The human circulatory system can be thought of as a closed system of interconnecting pipes through which fluid is continuously circulated by two pumps. The two pumps, the right and left ventricles of the heart, work as simple two-stroke force pumps. The muscles of the heart regulate the force by contracting and relaxing. The contraction (systole) lasts about 0.2 s, and a complete systole/diastole (contraction/relaxation) cycle lasts about 0.8 s. For blood pressures and speeds in the normal range, the volume flow rate of blood through a blood vessel is directly proportional to the pressure difference over a length of the vessel and to the fourth power of the radius of the vessel. The total mechanical energy per unit volume of blood just as it leaves the heart is:
E/V = ρ gh + P + 
ρ v 2
(i) Which of the following is a way to achieve approximately a 45% increase in the volume flow rate of blood through a blood vessel?
Text Solution
Verified by ExpertsCHECK THE SOLUTION.
Ans.
(i)
Sol. Volume flow rate
α Pressure difference
α (Radius of vessel) 4 (given in the passage)
If radius is increased by 10%, volume flow rate would be increased by a factor (1.1) 4 
1.44. This is the close enough to be the correct answer.
(ii)
Sol. Gravitational potential energy
= 
× volume
= (ρgh) (volume)
Here h is the height with respect to heart. Here is 0.3 m.
PE = 1050 × 9.8 × 0.3 × 8.0 × 10 –6
= 2.46 × 10 –2 J
(iii)
Sol. W = mgh = (200 × 10 –6 × 1050) (9.8) (0.5) 
1.0 J
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems