The heart is a four-chambered muscular organ that pumps blood through the body using rhythmic contractions. It has four chambers - the right and left atria which collect blood, and the right and left ventricles which pump blood out of the heart. The heart beats between 60-80 times per minute, pumping deoxygenated blood to the lungs and oxygenated blood to the rest of the body. Valves between the chambers allow blood to flow in only one direction to prevent mixing of oxygenated and deoxygenated blood.

1. Structure of heart

2. HEART The heart is a four-chambered muscular organs that pumps blood to all part of the body. It is able to do so by the rhythmic contraction and relaxation of its muscles. These are known as the heart beats . A normal heart beats about 60 to 80 times a minute . We can hear our heart beat with the help of an instrument called stethoscope.

3. REAL HEART.

4. THE FOUR CHAMBERS OF HEART ARE The right auricle The left auricle The right ventricle The left ventricle

5. `1 The right auricle opens into the right ventricle and the left auricle in to the left ventricle

6. Leftchambers Right chambers Left auricle Right auricle Right ventricle Left ventricle

8. PULSE As your heart beats and forces blood through your body , you would fell a throbbing sensation at any point where an artery comes close to the surface of your skin , such as wrist ,neck , or upper arm. This throbbing sensation is called the pulse.

10. Counting your pulse rate is simple way to estimate how fast your heart is beating .the pulse is often measured by a doctor as part of physical examination ,or an emergency, but you can easily learn to measure your pulse a s well.

11. RESTING PULSE. When you exercise , have a fever , or are under stress , your heart rate usually speeds up to meet your body’s increased need for oxygen and nutrients carried in the blood .the pulse is usually measured after you have rested or sat quietly for 10 minutes . This measurement is called resting pulse . The usually resting pulse for an adult is 50 to 100 beats per minute.

12. The walls of the auricles are thinner than those of the ventricles because the auricles have to pump blood into the ventricles ,which is very near. The walls of the ventricles are thicker ,since they have to push the blood to reach the farthest parts of the body .The blood in the right side of the heart remains completely separated from the left side with the help of valves.

13. Valves separate each of the chambers which allow blood to flow only into one direction. Thus , there is no mixing of oxygenated (oxygen-rich) and deoxygenated (carbon dioxide- rich )blood.

14. The veins get deoxygenated blood to the right auricle from all parts of the body. This blood is pumped into the right ventricle, which in turns pumps it into the pulmonary artery that takes it to the lungs for oxygenation.

15. In the lungs carbon dioxide diffuses out into the alveoli and oxygen diffuses in . The oxygen-rich blood is carried from the lungs to the heart by the pulmonary vein . Oxygenated blood enters the left auricle . It is then pumped into the left ventricle . The left ventricle then pumps the oxygenated blood to all parts of the body.

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17. DONE BY, SUKANYA.P.SUKESAN 7:K