The heart is a muscular organ that pumps blood through the circulatory system. It has four chambers - two upper atria and two lower ventricles - that work together to circulate blood. Oxygen-poor blood enters the right atrium from the body and is pumped to the lungs, where it receives oxygen before entering the left atrium. It then enters the left ventricle and is pumped back out to the body through the aorta. The heart valves prevent backflow of blood through the heart. This continuous cycle supplies the body with oxygenated blood and removes deoxygenated blood and carbon dioxide.

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2. BLOOD CIRCULATION IN HUMAN.
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By Rashmitha. M

3. THE HEART – ORGAN THAT HELPS IN CIRCULATION
 Heart is a fist-sized organ located in the chest cavity
slightly towards left. It is a strong muscular organ
made of cardiac muscles. The heart is a very crucial
organ of the body, it works nonstop. It is enclosed in
a thin membrane called pericardium and the fluid
present in between them is called pericardial fluid.
 The human heart consist of four chambers; mixing
of oxygenated and deoxygenated blood is resolved
by this four chambered design of heart, two on each
side. The two upper and smaller chambers are called
right auricle and left auricle. The two lower and
larger chambers are called right ventricle and left
ventricle.
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4. THE HEART – ORGAN THAT HELPS IN CIRCULATION
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 The two auricles are separated by are
separated by interauricluar septum and
the ventricles are separated by
interventricular septum. The left auricle
and left ventricle are separated by
bicuspid valve and the right auricle
and left ventricle are separated by
tricuspid valve, the right auricle has
venacava; the right ventricle has
pulmonary artery. The left auricle has
pulmonary veins and the left ventricle
has aorta.

5. CIRCULATORY SYSTEM
 All living organisms require few fundamental elements like food,
water and air to support their life. But how are these transported
from one place to another in our body? This function is done by the
circulatory system and heart which helps in the transportation of
food and other requirements to different parts if the body.
 Circulatory system as the name suggests it is a system which
circulates everything through out the body. The circulatory system,
also called the or the .
In order to circulate everything through out the body.
 Blood is a fluid present in our body which circulates food, water
and air to various body parts. Blood travels through a definite set of
paths called the blood vessels
 The main centre which pumps blood is the heart.
By Rashmitha. M
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6. The blood vessels that take part in blood circulation are arteries,
veins and capillaries.
1. ARTERIES :
The functions of arteries are :
 To carry oxygenated blood from right ventricles
to the lung for purification.
 The pulmonary artery carries deoxygenated
blood from the heart to lungs.
2. VEINS :
The functions of veins are :
 To carry deoxygenated blood from lungs to the left auricle of the heart.
 The pulmonary veins carry oxygenated blood from lungs to the heart.
By Rashmitha. M
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7. 3. CAPILLARIES :
The functions of capillaries are :
 To provide definite path for the flow of blood.
 To transfer the molecules of glucose, water, oxygen and hormones to the cells and tissues.
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8. Functions of the circulatory system :
 It transports nutrients from their sites of absorption to different tissues and
organs for storage, oxidation or synthesis of tissue components.
 It also carries waste products of metabolism from different tissues to the
organs meant for their excretion from the body.
 It transports respiratory gases between the respiratory organs and the
tissues.
 It carries metabolic intermediates from one tissue to another for their further
metabolism; for example, blood carries lactic acid from muscles to the liver for
its oxidation.
 It also transports informational molecules such as hormones, from their sites
of origin to the tissues.
 It uniformly distributes water, H+, chemical substances to all over the body.
By Rashmitha. M
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9.  During a heart beat, there is
contraction and relaxation of
auricles and ventricles in a
specific sequence. The contraction
phase is known as systole, while
relaxation phase is known as
diastole. Various series of events
that occur during a heart beat is
known as cardiac cycle. By Rashmitha. M
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Course of Circulation through Heart :

10.  When both the auricles and ventricles
are in relaxed or diastolic phase. This is
referred to as joint diastole. During this
phase, the blood flows into the auricles
from the superior vena cava and inferior
vena cava. The blood also flows from the
auricles to their respective ventricles
through the atrio-ventricular valve.
There is no flow of blood from the
ventricles to the aorta and its main
arteries as the semilunar valves remain
closed in this phase.
By Rashmitha. M
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11. How Does Blood Flow Through the Heart?
The right and left sides of the
heart work together. The
pattern described below is
repeated over and over, blood to
flow continuously to the heart,
lungs, and body.
By Rashmitha. M
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12. RIGHT SIDE
 Blood enters the heart through two large veins, the inferior and
superior vena cava, emptying oxygen-poor blood from the body
into the right atrium.
 As the atrium contracts, blood flows from your right atrium
into your right ventricle through the open tricuspid valve.
 When the ventricle is full, the tricuspid valve shuts. This
prevents blood from flowing backward into the atria while the
ventricle contracts.
 As the ventricle contracts, blood leaves the heart through the
pulmonic valve, into the pulmonary artery and to the lungs
where it is oxygenated.
By Rashmitha. M
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13. LEFT SIDE
 The pulmonary vein empties oxygen-rich blood from the
lungs into the left atrium.
 As the atrium contracts, blood flows from your left
atrium into your left ventricle through the open mitral
valve.
 When the ventricle is full, the mitral valve shuts. This
prevents blood from flowing backward into the atrium
while the ventricle contracts.
 As the ventricle contracts, blood leaves the heart
through the aortic valve, into the aorta and to the body.
By Rashmitha. M
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14.  The atria and ventricles work together, contracting and relaxing to
pump blood out of the heart. As blood leaves each chamber of the
heart, it passes through a valve. There are four heart valves within
the heart:
Mitral valve
Tricuspid valve
Aortic valve
Pulmonic valve (also called pulmonary valve)
 The tricuspid and mitral valves lie between the atria and ventricles.
The aortic and pulmonic valves lie between the ventricles and the
major blood vessels leaving the heart.
 The heart valves work the same way as one-way valves in the
plumbing of your home. They prevent blood from flowing in the
wrong direction. By Rashmitha. M
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15. Each valve has a set of flaps, called leaflets or cusps. The
mitral valve has two leaflets; the others have three. The
leaflets are attached to and supported by a ring of tough,
fibrous tissue called the annulus. The annulus helps to
maintain the proper shape of the valve.
The leaflets of the mitral and tricuspid valves are also
supported by tough, fibrous strings called chordae
tendineae. These are similar to the strings supporting a
parachute. They extend from the valve leaflets to small
muscles, called papillary muscles, which are part of the
inside walls of the ventricles. By Rashmitha. M
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16.  Once blood travels through the pulmonic valve, it enters your
lungs. This is called the pulmonary circulation. From your
pulmonic valve, blood travels to the pulmonary artery to tiny
capillary vessels in the lungs.
 Here, oxygen travels from the tiny air sacs in the lungs,
through the walls of the capillaries, into the blood. At the
same time, carbon dioxide, a waste product of metabolism,
passes from the blood into the air sacs. Carbon dioxide leaves
the body when you exhale. Once the blood is purified and
oxygenated, it travels back to the left atrium through the
pulmonary veins.
By Rashmitha. M
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How Does Blood Flow Through Your Lungs?

17. Like all organs, your heart is made of tissue
that requires a supply of oxygen and
nutrients. Although its chambers are full of
blood, the heart receives no nourishment from
this blood. The heart receives its own supply of
blood from a network of arteries, called the
coronary arteries.
By Rashmitha. M
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Did you KNOW??

18. Let Us Look A Video For Better Understanding Of The
Function Of Heart.
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19. By Rashmitha. M
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