Question

answer this question

BLOOD AND FLUID QUESTION 1 (0A patient's blood pressure taken at the arm is 120 mmHg systolic and 70 mmHg diastolic. What would you expect the blood pressure (systolic and diastolic pressures) to be at the top of the head given that this point is 40 cm above the measurement point? Remember blood pressure is a gauge pressure and that 1 kPa = 7.5 mmHg. (The density of blood is about 1060 kg/m.) Choose one: a. 89 mmHg systolic pressure and 39 mmHg diastolic pressure b. 105 mmHg systolic pressure and 45 mmHg diastolic pressure c. 99 mmHg systolic pressure and 54 mmHg diastolic pressure d. 94 mmHg systolic pressure and 59 mmHg diastolic pressure (1) Assume each blood vessel has the same diameter 25 mmHg 50 mmHg pressure 25 mmHg pressure 75 mmHg pressure pressure Blood Vessel A Blood Vessel B What is the pressure difference in blood vessel A: What is the pressure difference in blood vessel B: How much faster will the blood flow in vessel B be compared with vessel A: ii) When athletes use erythropoietin (EPO) to increase the oxygen carrying capacity of their blood they increase their haematocrit (numbers of red blood cells per ml of blood). As a consequence, their blood viscosity also increases. How would this increased haematocrit potentially influence an athlete's blood flow and blood pressure? Choose one: a. Blood flow could decrease, blood pressure could increase. b. Blood flow could decrease, blood pressure could decrease. c. Blood flow could increase, blood pressure could decrease. d. Blood flow could increase, blood pressure could increase. (iv) Blood flows through the femoral vein at a rate of 0.035 litre/second. When the leg is relaxed the femoral vein has a cross-sectional area, A. of 0.5 x 10-m. When walking the leg muscles contract and the cross-sectional area of the femoral vein decreases by half. What is the velocity of the blood flow in the femoral vein at rest and during exercise? Assume the blood flow rate is the same at rest and during exercise. Select one: a. Velocity at rest is 0.0175 m/sec and the velocity during exercise is 0.035 m/sec. b. Velocity at rest is 0.07 m/sec and the velocity during exercise is 0.14 m/sec. c. Velocity at rest is 14.28 m/sec and the velocity during exercise is 28.57 m/sec. d. Velocity at rest is 0.7 m/sec and the velocity during exercise is 1.4 m/sec. Nords LE Foolish Australia Focus

Answer 1

arm bp = 120mm/70mm

height of head= 40cm ; density = 1060 Kg/m^3

pressure diiferential = 0.4 m x 9.81 m/s^2 x 1060 Kg/m^3

1Pa = 7.5 x 10^(-3) mm of Hg

pressure differential in mm = 0.4 m x 9.81 m/s^2 x 1060 Kg/m^3 *[7.5 x 10^(-3) mm of Hg]

= 31.0 mm

sistolic = 120-31.0 = 89mm

diastolic = 70mm -31 mm = 39mm

-------------------------------------------

(ii). systolic: 50 mm of Hg in A = 50 x (1000/7.5) Pa

diastolic : 25 mm of Hg in A = 25 x (1000/7.5 ) Pa

Difference in pressure = (50-25) x (1000/7.5) Pa = 0.5 x 1060 Kg/m^3 x v^2

v(A) = sqrt (25*1000/(7.5*1060*0.5)) = 2.51 m/s

v(B) = sqrt (50*1000/(7.5*1060*0.5) = 3.55 m/s

V(B) - V(A) = 1.04 m/s

(iii)

Blood flow could reduce,BP could increase

(iv)

A V = quantity per sec

0.5 x 10^(-4) m^2 x V = 0.035 L/s = 0.035 x 0.001 m^3/s

V = 0.035 x 0.001 m^3 / (0.5 x 10^(-4)) = 0.7 m/s ( rest)

Since area is becoming half while excercising , velocity will double and become 1.4 m/s(excercise)