structure of heart, auricle , ventricle, working of heart, circulation of blood, pulmonary vein, pulmonary artery, heart beat and heart sounds

1. Transportation in humans
(Structure and function of heart)
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2. Heart
• Heart:- heart is a living pump.
• Location:- it is situated between lungs in our
chest cavity.
• Heart is made of:- Cardiac muscles. These
muscles contract and relax tirelessly throughout
life.
• Speciality of cardiac muscles:- It makes heart
beat continuously and pumps blood into the
arteries to be transported to all parts of the body.
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Structure of heart

4. - Human heart is 4 chambered.
- It Has 2 auricles or atria. And 2 ventricles.
- Heart is divided into two half by thick muscular
septum. With auricle above and ventricle below.
- Right half of heart has Right auricle and right ventricle.
- Left half of heart has left auricle and left ventricle.
- Right half of heart = deoxygenated blood( blood
coming from body and will be pumped to lungs
for removing carbon dioxide).
- left half of heart = oxygenated blood ( blood coming
from lungs filled with oxygen and will be pumped
to the body parts).
- Septum:- Septum prevents mixing of oxygenated
blood with deoxygenated blood.
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5. Auricles
• Auricles:-
- Auricles are the receiving chambers of the
heart.
- Right auricle receives deoxygenated blood
from the whole body.
- Left auricles receives oxygenated blood from
lungs.
- The walls of auricles are thinner than those of
ventricles.
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6. Ventricles
• Ventricles pumps the blood out in the body.
• Right ventricle:- receives deoxygenated blood
from right auricle. Pumps blood to lungs for
oxygenation.
• Left ventricle:- ( largest heart chamber and
has thickest walls). It receives oxygenated
blood from left auricle. Pumps it to whole
body.
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7. Valves
• There are 4 valves in the heart.
• Function of valve:- to control the flow of
blood in the heart and in blood vessels.
• A tricuspid valve:- guards the opening of right
auricle and right ventricle.
• A bicuspid valve:- guards the opening of left
auricle and left ventricle.
• Semilunar valve:- they are present at the base
of pulmonary Aorta and dorsal aorta.
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8. Working of heart and circulation of
blood
• Auricles gets relaxed and both auricles gets filled
with blood.
• Right auricle receives deoxygenated blood from
body.
• Left auricle receives oxygenated blood from lungs
by pulmonary veins.
• Note:- Veins bring deoxygenated blood from
entire body to heart. But pulmonary vein means
the vein coming from lungs. Pulmonary veins
carry oxygenated blood.
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10. - Both auricle contract and their cuspid valve open up.
- Blood from left auricle comes to left ventricle.
- Blood from right auricle comes to right ventricle.
- Both atrium relax and new blood flow into both
chambers.
- At the same time ventricle contract. The cuspid valves
are slam shut and Semilunar valves open up.
- The oxygenated blood from left ventricle is pumped
into aorta and distributed to all body parts by arteries.
- The deoxygenated blood from right ventricle is
pumped into pulmonary aorta and transported to lungs
for oxygenation by pulmonary arteries.
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11. Pulmonary Vein
• Vein:- Veins are those blood
vessel having their starting
point in capillaries. Veins
coming from body parts
contain deoxygenated blood.
• Pulmonary vein:- The blood
vessels which arise from
capillaries in lungs contain
oxygenated blood. Hence
pulmonary vein carry
oxygenated blood from lungs
to heart. Which is then
circulated in entire body.
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12. Pulmonary artery
• Artery:- Those blood vessels
which divide and re-divide
into smaller units to form
capillaries is called artery.
• Pulmonary artery:- the
blood vessels which divide
itself into smaller units in
lungs contain deoxygenated
blood. Hence pulmonary
artery carry deoxygenated
blood from heart to lungs
for oxygenation.
(oxygenation means adding
oxygen).
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13. Heart beat
• Heart beat:- rhythmic contraction and relaxation of
auricle and ventricle is known as heart beat. ( heart
beats about 72 times per minute.)
• One heart beat:- one heart beat includes a phase of
contraction of heart muscles and a phase of relaxation
of heart muscles.
• Systole:- A phase of contraction of heart muscles.
During this phase auricle contract to push blood to
ventricle. And ventricle contract to circulate blood in
whole body.
• Diastole:- A phase of relaxation of heart muscles.
During this phase heart receives blood.
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14. Heart beat sound
• The heart beat sound is produced by the
contraction of muscles and shutting down of
valves.
• The two phases of heart beat can be heard as Lub
and Dub sounds.
• Lub sound:- produced when the ventricle
contract and cuspid valve close.
• Dub sound:- produces when the pulmonary and
aortic valves close.
• Stethoscope is the instrument use to hear the
heart beat.
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