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Heart Sounds
First heart sound or lubb Atrioventricular valves and surrounding fluid
vibrations as valves close at beginning of ventricularsystole
Second heart sound or dupp Results from closure of aortic and pulmonary
semilunar valves at beginning of ventricular diastole,lasts longer
Third heart sound (occasional) Caused by turbulent blood flow into ventricles and
detected near end of first one-third of diastole
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Cardiac Arrhythmias
Tachycardia: Heart rate in excess of 100bpm
Bradycardia: Heart rate less than 60 bpm
Sinus arrhythmia: Heart rate varies 5% during
respiratory cycle and up to 30% during deeprespiration
Premature atrial contractions: Occasional
shortened intervals between one contraction andsucceeding, frequently occurs in healthy people
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Heart Homeostasis
Effect of blood pressure Baroreceptors monitor blood pressure
Effect of pH, carbon dioxide, oxygen Chemoreceptors monitor
Effect of extracellular ion concentration Increase or decrease in extracellular K+ decreases
heart rate
Effect of body temperature Heart rate increases when body temperature
increases, heart rate decreases when bodytemperature decreases
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Baroreceptor Reflex
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Chemoreceptor Reflex-pH
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Effects of Aging on the Heart
Gradual changes in heart function, minorunder resting condition, more significantduring exercise
Hypertrophy of left ventricle Maximum heart rate decreases
Increased tendency for valves to function
abnormally and arrhythmias to occur Increased oxygen consumption required to
pump same amount of blood
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The artery used to determine BP is the brachial artery,which runs down the upper arm, splitting into the radial
and ulna arteries near the elbow.
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Normal systolic pressure is about 120 mm Hg for males, AND 110 mm Hg for females.
This measurement is the systolic pressurethe pressure of the blood when the ventricles contract.
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Diastolic pressure - pressure when the ventricles are relaxed.
Normal diastolic pressure is about80 mm Hg for males & 70 mm Hg for females.
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Blood pressure is reported in millimeters of mercury(mm Hg) with the systolic pressure written first.
The pressure measuredin this example is 120/80.
Measuring Blood Pressure
with a Sphygmomanometer
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BLOOD LOSS
Brachial artery - 0.5 lt
Ribs - 2 lt
Sacrum - 2lt
Femur - 1.5 lt
Tibia/fibula - 1lt
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