Download Human Cardiovascular Physiology

Human Cardiovascular Physiology
Overview
In this exercise, students will be introduced to the common methods of monitoring pulse, measuring blood pressure (using a
sphygmomanometer), and listening to the major heart sounds (auscultation using a stethoscope). In addition, students will utilize
plethysmography (using a photoelectric pulse transducer) to monitor pulse rate and pulse pressure while performing the Valsalva
maneuver.
Introductory Notes
Dicrotic Notch
Systolic
Pressure
MAP
•
•
•
•
•
Diastolic
Pressure
Systolic Pressure: pressure exerted by the blood against the arterial walls during ventricular systole (normal ≈ 120 mmHg)
Dicrotic Notch: due to the brief backflow of blood through the elastic arteries which closes the semilunar valves during
ventricular diastole
Diastolic Pressure: pressure exerted by the blood against the arterial walls during ventricular diastole (normal ≈ 80 mmHg)
Pulse Pressure: is the difference between the Systolic Pressure and the Diastolic Pressure (SP - DP); and is the “throb” felt
when taking a pulse (normal ≈ 40 mmHg: 120 mmHg - 80 mmHg)
Mean arterial pressure (MAP) = a calculated “average” pressure within the arteries; during the cardiac cycle
MAP = Diastolic Pressure + 1/3 (Pulse Pressure)
Note: The equation reflects the fact that the heart spends more time in diastole during the cardiac cycle; therefore, not
merely an average between SP and DP.
Example: If BP is recorded as 120mmHg/80mmHg (Vent Systolic P / Vent Diastolic P)
MAP
MAP
MAP
MAP
MAP
=
=
=
=
=
DP + 1/3 (SP – DP)
80 + 1/3 (120 – 80)
80 + 1/3 (40)
80 + 13.33
93.33 mmHg
Plethysmography = the study of blood volume change within an organ/tissue (or organism) by using volume displacement
techniques
- blood volume changes are monitored with a photoelectric pulse transducer placed on the finger
Heart Sounds
• 1st heart sound: closure of AV valves; 2nd heart sound: closure of SL valves
• Murmur: an abnormal heart sound associated with valvular insufficiency, and/or narrowing of the valvular opening
Experimental Procedures
Pulse Rate: Before beginning the exercise, practice using your second and third fingers to palpate the radial artery of your
laboratory partner and determine the pulse rate for 15 seconds. Repeat the same procedure while palpating the carotid artery.
Is there a difference in the pulse strengths at the two locations?
Determine the radial pulse rate of your laboratory partner (for 60 seconds) under the following conditions:
1)
After your partner has rested 5 minutes in a supine position. Record your data.
2)
Immediately after your partner assumes a sitting position. Record your data.
3)
Immediately after your partner assumes a standing position. Record your data.
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Auscultation of Heart Sounds: Before beginning the exercise, clean the earpieces of the stethoscope with an alcohol swab. Repeat
this procedure again after completing the exercise. For comfort and best auscultation, the earpieces should be angled slightly in a
forward direction when placed in the ears.
1)
2)
3)
Distinguish between the two major heart sounds (“lubb-dupp”).
Listen for sounds created by all four valves and compare the loudness, pitch, and duration of each.
(See the illustration for correct positioning of the stethoscope to differentiate individual valve sounds.)
Measure the radial pulse and apical pulse (pulse determined via auscultation) simultaneously, to determine if
a “pulse deficit” exists. Record your data.
Measurement of Blood Pressure: Before beginning the exercise, clean the earpieces of the stethoscope with an alcohol swab.
Repeat this procedure again after completing the exercise. Obtain a sphygmomanometer and test to make sure the bulb, valve, and
gauge are all functioning properly.
Determine the blood pressure of your subject under the following conditions:
1)
After your partner has rested 2 minutes in a sitting position. Record your data.
2)
After your partner has rested 2 minutes in a supine position. Record your data.
3)
After your partner has rested 2 minutes in a standing position. Record your data.
4)
Immediately after your partner has exercised 5 minutes and assumes a sitting position. Record your data.
5)
From the original sitting position data above, calculate the mean arterial pressure (MAP) and record your finding.
Plethysmography is the study of blood volume changes within an organ/tissue by using volume displacement techniques. Changes
in tissue or organ volume associated with peripheral vasodilation/vasoconstriction or associated with each cardiac cycle may be
photoelectrically detected, and the signal may be transduced into an electric current, amplified, and recorded as a time record of
volume change. In this exercise, a photoelectric pulse transducer will be utilized to monitor blood volume changes in the finger.
Connect the pulse transducer to Channel 1 on the BioPac acquisition box. Click on the “Pulse” folder on your desktop to record your
data.
1)
2)
3)
While your partner is seated with their hand resting on the lab table, record their pulse for 10 seconds. Note which
components of the cardiac cycle are discernible in the recording. Calculate the resting pulse rate using the BPM tool and
record your data.
a. BPM tool: select an area with the I-beam cursor that represents one complete beat-to-beat interval. This tool
calculates the difference in time between the first and last selected points and divides this value into 60 seconds /
minute to determine beats per minute.
With your partner standing, record their pulse for 10 seconds. Calculate the pulse rate and record your data. Compare the
pulse rates and pulse recording amplitudes of the “sitting” subject with the “standing” subject.
While your partner is seated with their hand resting on the lab table, record their pulse while they perform the Valsalva
maneuver (in which the subject, after a deep inspiration, forces expiration against a closed glottis). Note the changes in
pulse rate and pulse recording amplitude at the onset of the maneuver, during the maneuver, immediately after the
maneuver, and 2 seconds after the maneuver. Explain the changes.
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Name:____________________
DATA SHEET: Human Cardiovascular Physiology
Exercise: Pulse Rate
Radial pulse after 5 minute rest, supine position: ____________beats/min
Radial pulse immediately after assuming sitting position ____________beats/min
Radial pulse immediately after assuming standing position ____________beats/min
Exercise: Auscultation of Heart Sounds
• Compare the differences in heart sounds created by the AV and SL valvular action. Describe differences in loudness,
pitch, and duration:
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
• Apical pulse: ____________beats/min
• Radial pulse: ____________beats/min
• Pulse Deficit: __________beats (apical pulse – radial pulse)
Exercise: Measurement of Blood Pressure (Systolic Pressure / Diastolic Pressure)
• Sitting position: Trial 1 ____________ Trial 2 ____________
• Supine position: ____________ • Standing position: ____________
• Sitting position immediately after exercise: ____________
• Calculated “mean arterial pressure” MAP (from resting sitting position data above): ____________
Exercise: Plethysmography
• Pulse rate in sitting position: ____________beats/min
• Pulse rate in standing position: ____________beats/min
• Explain the differences observed in pulse rates and pulse recording amplitudes of “sitting” and “standing” data and why they
occur. ___________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
• Explain the differences observed in pulse rates and pulse recording amplitudes at different time intervals: before, during
performance of the Valsalva maneuver, and after. Why do these differences occur?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
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