The document discusses pulse rate measurement and factors that affect pulse. It describes how the pulse is the pressure wave felt when the heart contracts and can be measured at various points like the wrist. The pulse rate is affected by age, gender, exercise, medications, stress, fever, blood loss, and certain diseases. It also discusses different methods of measuring pulse like using a photoresistor over the finger in transmittance and reflectance methods.
2. PULSE
• When heart muscle contracts, blood is ejected from the ventricles and a pulse of
pressure is transmitted through the circulatory system.
• This pulse is measured at various points and we can sense by placing our fingertip
over the radial artery in the wrist.
• Pulse travels at a speed of 5 to 15 meters/second
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3. PULSE
• The apical pulse is a central pulse; that is, it is located at the apex of the
heart.
• It is also referred to as the point of maximal impulse (PMI).
• The rate of the pulse is expressed in beats per minute (BPM).
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4. FACTORS AFFECTINGTHE PULSE
• Age -As age increases, the pulse rate gradually decreases overall.
• Gender -The average male’s pulse rate is slightly lower than the female’s.
• Exercise -The pulse rate normally increases with activity.
• Medications - Some medications decrease the pulse rate, and others increase it
• Fever -The pulse rate increases
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5. CONTINUED . . .
• Hypovolemia - Loss of blood from the vascular system normally increases pulse
rate.
• Stress - In response to stress, sympathetic nervous stimulation increases the
overall activity of the heart.
• Pathology - Certain diseases such as some heart conditions or those that impair
oxygenation can alter the resting pulse rate.
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9. TRANSMITTANCE METHOD
• LED and photoresistor are used
• They are fitted over the tip of the finger
• Light is produced by LED and the same light is passing through the finger.
• For each heart pulse the amount of blood is forced and flow of blood is increased and
density is changed.
• Light received by photoresistor.
• Photoresistor is connected to voltage divider circuit.
• Voltage produced by the circuit is directly proportional to the amount of blood flow in
the finger.
• Output is recorded using strip chart recorder.
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10. REFLECTANCE METHOD
• LED is placed adjacent to photoresistor.
• LED emits the light.The light is reflected from the skin and the tissues and fall on the
photoresistor.
• Reflected light varies depending on the blood flow in the finger.
• Photoresistor is connected to voltage divider circuit.
• Voltage produced by the circuit is directly proportional to the amount of blood flow in
the finger.
• Output is recorded using strip chart recorder.
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