Human Cardiovascular Function

DEPARTMENT OF PHYSIOLOGY

PHY2021

Body Systems Physiology

Human Cardiovascular Function

Worksheet

Due by:

Monday class by 11am on 30th April

Tuesday class by 10am on 1st May

Wednesday class by 10am 2nd May

Thursday class by 10am 3rd May

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OBSERVATIONS OF HUMAN CARDIOVASCULAR FUNCTION

Part 1 The Arterial Pulse

1. Why is it possible to feel the arterial pulse in a superficial artery?

It is possible to feel the pulse from superficial arteries as they are closer to the surface. Also arteries contract

and expand more readily than veins allowing for easier detection.

Part 2 Indirect Measurement of Human Blood Pressure

1. Record in the Table below the systolic and diastolic blood pressure determined by the Auscultatory Method in three group members.

Also record in the table the pulse pressure and mean arterial pressure for each subject

Subject 1 Subject 2 Subject 3

Systolic/Diastolic Pressure (mmHg) 112/78 127/78

Pulse Pressure

(mmHg) 34 49

Mean Arterial Pressure

(mmHg) 89.3 94.3

2. Record in the Table below the systolic and diastolic blood pressure determined using the cardiomicrophone in the same group members as for question 1.

Also record in the table the pulse pressure and mean arterial pressure for each subject

Subject 1 Subject 2 Subject 3

Systolic/Diastolic Pressure (mmHg) 118/63 124/65

Pulse Pressure

(mmHg) 55 59

Mean Arterial Pressure

(mmHg) 81.3 84.7

3. List below the systolic blood pressure determined using the finger pulse transducer in the same group members as for question 1.

Subject 1 Subject 2 Subject 3

Systolic Pressure

mmHg 78

4. In one subject from your group, list below the systolic blood pressure determined with the hand hanging loosely down by the side (below Heart), on the desk or chair arm (Heart Level) and above the head (Above Heart).

Below Heart Heart Level Above Heart

Systolic Pressure

mmHg 98 98 86

5. Suggest two possible sources of error or variation in the auscultatory technique for blood pressure measurement?

Noise pollution, affecting the result

Improper interpretation (mistake) of the sounds which occur when cuff is at systolic/diastolic pressures

6. Explain the underlying cause of the Korotkoff sounds that you detected with the cardiomicrophone as the cuff pressure was decreased.

When the pressure cuff is inflated above the systolic pressure of the subject the blood flow is obstructed giving

no sounds. When the pressure is then allowed the drop below systolic levels blood will begin to spurt pass the

obstruction creating audible sounds. These sounds continue until diastolic pressure is reached where the

sounds become muted and eventually silenced.

7. Why does the finger pulse transducer, which operates on the same principle as the palpatory method (Riva Rocci), tend to give systematically low estimates of systolic blood pressure?

Basically this is because the pulse can be heard before it can be felt. As the pressure cuffs deflate to systolic

pressures faint sounds can be heard by a stethoscope. A pulse is harder to feel so the cuff has to be deflated

more to get stronger palpable pulses. Hence when using the palpatory method the cuff will be at a lower

pressure before palpitations will be felt

8. Do you think that pulse measurement can replace the stethoscope in determining diastolic pressure? Why?

No, as once the pressure cuff is lower than systolic pressures a pulse will be felt and it will be difficult to pinpoint

when the pulse disappears as it reaches diastolic pressures

9 Briefly explain why the arterial pressure measured using the finger pulse is different with the arm in different positions.

The difference in blood pressure is due to hydrostatic pressure. In a column of liquid the pressure is at its lowest

at the top and increases as we go down the column giving the highest pressures at the bottom, the same goes

for the blood in our body resulting varying blood pressures at different heights.

Part 3 Effect of Posture & Exercise on Heart Rate & Arterial Blood Pressure

1. Record in the Table below the systolic and diastolic blood pressures and heart rate as recorded by the Omron automatic blood pressure monitor in two of the same group members as above.

Subject 1 Subject 2

Systolic/Diastolic Pressure (mmHg) 124/65 118/63

...