Question

4. Consider a hypothetical circulatory system composed of 5 capillary beds arranged in parallel. Each capillary bed has a resistance of 3 PRU The total mean pressure gradient in this systenm is 100 mm Hg. a. Calculate the total resistance for this circulatory system (parallel). b. Calculate the flow rate (in ml/sec) through one capillary bed. What would the total flow rate through this parallel system be (now calculate flow for 5 beds in parallel)? c. d. Calculate the total resistance of a circulatory system in which the 5 capillary beds aren series (each having an individual resistance, 3 PRU, as given above. e. What would the flow rate be through this circuit of 5 capillary beds in series?

Answer 1

Each capillary system of resistance is 3 PRU.

a. Total resistance for this circulatory system in parallel is

Rt= (1/R1+ 1/ R2+ 1/ R3+ 1/R4 + 1/R5)^-1

Rt = (1/3+ 1/3+ 1/3+ 1/3 + 1/3 + 1/3)^-1

Rt= (5/3)^-1

Rt= 3/5 = 0.6

b.The flow rate through one capillary bed is

Q = Mean pressure gradient / resistance in capillary bed

= 100 / 3= 33.33 ml/min

= 33.33 / 60 = 0.55 ml/ sec

Flow rate Q is 0.55 ml/sec

C. Total flow rate through this parallel system is

Qt= 100/ 0.6= 166.67 ml/ min or 2.77 ml/sec

d. Total resistance for a circulatory system in series is

Rt= R1+ R2+ R3 + R4 + R5 = 3+3+3+3+3=15

Rt = 15

e. Flow rate in series of capillary system is 33.33 ml/min or 0.55 ml/sec