Cardiovascular System printable pdf download

Problem Set #4

Cardiovascular System - Answer Key

Fill in your answers on the answer sheet. Show your calculations and include proper units.

1. Maria’s heart rate is 90 beats/min and her cardiac output is 5,400 mL/min. What is Maria’s

stroke volume?

C.O. = HR x SV

SV = C.O. / HR

(5,400 mL/min)

= 60 mL / beat

(90 beats/min)

2. Joe’s systolic blood pressure is 155 mm Hg and his diastolic pressure is 95 mm Hg.

a) What is Joe’s pulse pressure?

Pulse P = Systolic P – Diastolic P

(155 mm Hg) – (95 mm Hg) = 60 mm Hg

b) What is Joe’s mean arterial pressure?

(95 mm Hg) + ⅓ (60 mm Hg) = 115 mm Hg

MAP = Diastolic P + 1/3 (Pulse P)

c) What is Joe’s condition?

hypertension (stage 1)

3. The graph below shows Alice’s left ventricular volume during a cardiac cycle.

a) What is the name of the specific phase marked “A”?

isovolumic contraction

b) What is the name of the phase marked “B”?

ventricular ejection

c) Is the blood pressure in the left ventricle higher in phase A or phase B?

phase B

Blood pressure reaches its highest point during ventricular ejection.

d) What is Alice’s stroke volume?

SV = EDV – ESV

(130 mL) – (70 mL) = 60 mL

e) If Alice’s heart rate is 80 beats/min, what is her cardiac output?

C.O. = HR X SV

(80 beats/min) x (60 mL/beat) = 4,800 mL/min

4. Dave’s resting heart rate is 50 beats/min and his stroke volume is 100 mL. When Dave runs

up the Skyline Trail, his heart rate increases to 160 beats per minute and his stroke volume

increases to 150 mL. By what factor (how many times) does his cardiac output increase during

running relative to rest?

Resting C.O. = (50 beats/min) x (100 mL/beat) = 5,000 mL/min

Exercise C.O. = (160 beats/min) x (150 mL/beat) = 24,000 mL/min

Factor of increase = (24,000 mL/min) / (5,000 mL/min) = 4.8 times

5. Dave’s resting blood pressure is 120/75 mm Hg (systolic/diastolic) When he is running up the

Skyline Trail, his blood pressure increases to 145/85.

a) Calculate Dave’s mean arterial pressure during rest and during running.

Resting MAP = 75 mm Hg + ⅓ (45 mm Hg) = 90 mm Hg

Exercise MAP = 85 mm Hg + ⅓ (60 mm Hg) = 105 mm Hg

b) By what factor (how many times) does his MAP increase during exercise?

Factor of increase = (105 mm Hg) / (90 mm Hg) = 1.2 times

Cardiovascular System

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