6. Heart Valves
• Heart valves ensure
unidirectional blood flow
through the heart.
• Atrioventricular (AV) valves lie
between the atria and the
ventricles
– AV valves prevent backflow into
the atria when ventricles
contract.
1. Tricuspid Valve (Right chamber)
2. Bicuspid valve or Mitral valve
(Left valve)
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7. Heart Valves
• Semilunar valves prevent
backflow of blood into
the ventricles.
3. Aortic semilunar valve
lies between the left
ventricle and the aorta.
4. Pulmonary semilunar
valve lies between the
right ventricle and
pulmonary trunk.
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8. Pathway of Blood Through the Heart
and Lungs
• Right atrium tricuspid valve
right ventricle
• Right ventricle pulmonary
semilunar valve pulmonary
arteries lungs
• Lungs pulmonary veins
left atrium
• Left atrium bicuspid valve
left ventricle
• Left ventricle aortic
semilunar valve aorta
• Aorta systemic circulation
Right atrium
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9. S.N. Parameter Arteries Veins
01 Walls Thick Thin
02 Lumen Narrow Wider
03 Valves Absent except Aorta &
Pulmonary
Present
04 Pressure Blood is under high
pressure.
Blood is under low
pressure.
05 Type of blood
carry
Oxygenated except
Pulmonary artery.
Deoxygenated except
Pulmonary veins.
06 --- Carry blood away from the
heart.
Carry blood towards
heart.
07 Colour Red Blue
08 Location Placed deeper as compared
to veins.
Placed superficially
as compared to
arteries.
09 Pulse Detectable Usually not
detectable.
Difference between Arteries and Veins
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10. Conducting system of Heart
1. SA Node
2. AV Node
3. Bundle of
HIS
4. Bundle
Branches
5. Purkinje
fibres
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12. Cardiac Cycle
• Cardiac cycle refers to all events occuring in
the heart during each heart beat.
– Systole – contraction of heart muscle
– Diastole – relaxation of heart muscle
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13. Stages of Cardiac cycle
• Atrial systole – Contraction of Atria (0.1 Sec)
• Ventricular systole – Contraction of Ventricles (0.3
Sec).
• Complete cardiac diastole – Relaxation of Atria &
Ventricles (0.4 Sec).
Each cardiac cycle completed in 0.8 sec
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16. Cardiac Output (CO)
• Cardiac Output is the amount of blood pumped
by each ventricle in one minute
– CO is the product of heart rate (HR) and stroke
volume (SV)
• HR is the number of heart beats per minute
• SV is the amount of blood pumped out by a ventricle with
each beat
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CO (ml/min) = HR (75 beats/min) x SV (70
ml/beat)
CO = 5250 ml/min (5.25 L/min)
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17. Heart Sounds
• Heart sounds (lub-dup) are associated with
closing of heart valves
– First sound occurs as AV valves close and signifies
beginning of systole (contraction)
– Second sound occurs when SL valves close at the
beginning of ventricular diastole (relaxation)
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18. Blood Pressure
• BP is defined as pressure exerted by the blood
on the walls of blood vessels.
• Phases of Arterial B.P.—
1. Systolic B.P.- 120 mmHg (100-140mmHg).
2. Diastolic B.P. – 80 mmHg (75-85mmHg).
3. Pulse pressure – 40 mmHg (30-50 mmHg).
Blood Pressure = Cardiac output ×
Peripheral resistance
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