THE HEART

1. THE HEART
ASWATHY SUDHAKARAN
NATURAL SCIENCE
CTE PAIPPAD

2.  The heart is situated slightly tilted towards the left in between the two
lungs, Behind the sternum in the thorasic cavity.
 The size of the human heart is equal to the size of one’s fist.
 The heart work like a pump, blood flow through blood vessels
continuously in all direction.
 The pump oxygen and nutrient rich blood to the organ, tissues and cell of
the Body, and eliminate waste products.
THE HEART

3. LONGITUDINAL SECTION OF HEART

4.  The heart is covered by a double layered membrane called pericardium. pericardial fluid is filled
in between the pericardial membrane . This fluid help to reduce friction between the membrane.
 The heart has four chambers .
 Right atrium
 Right ventricle
 Left atrium
 Left ventricle
 VEIN- The blood vessel which carry blood to the heart.
 ARTERY- Blood vessel which carry blood from the heart.
STRUCTURE OF HEART

5. HEART VALVES
 TRICUSPID VALVE - Located between the right atrium and the right ventricle.
 PULMONARY VALVE –Located between the right ventricle and the pulmonary artery.
 BICUSPID VALVE – Located between the left atrium and left ventricle.
 AORTIC VALVE – Located between the left ventricle and the aorta

6. Working of heart
 Blood enters the heart through the inferior and superior venacava and is pumped into the right atrium of the
heart.
 As the atrium contracts, blood flows from the right atrium into the right ventricle through the open tricuspid
valve.
 When the ventricle is full ; the tricuspid valve shuts, preventing a backflow of blood into the atria.
 Blood leaves the right ventricle heart through the pulmonic valve, into the pulmonary artery and to the lungs
where it is oxygenated.
 The pulmonary vein impties oxygen rich blood from the lungs into the left atrium of the heart.
 As the atrium contract, blood flows from the left atrium into the left ventricle through the open bicuspid valve.
 When the ventricle is full ;the bicuspid valve shuts, preventing a back flow of blood into the atrium.
 As the ventricle contracts, blood leaves the heart through the aortic valve, into the aorta and to the body.

8.  Continous and rhythemic beating is a characteristic feature of the heart.
 Initiation of the contraction and relaxation of the heart and regulation of the heartbeat rate are carried out
by the special muscle of sino atrial node (SA node) at the anterior part of right atrium. This part is called
pacemaker.
 Contraction of chambers heart is termed as systole, and the stage of relaxation is termed as diastole.
 One systole and the subsequent diastole together constitute a heartbeat.
 It takes about 0.8sec.

9. DOUBLE CIRCULATION

10. When blood flows from the heart to different parts of the body and vice versa,it passes twice through
the chambers of the heart. Hence the circulation of blood in man is said to be double circulation.
Double circulation include systemic circulation and pulmonary circulation.
 systemic circulation starts from the left ventricle and ends in the right atrium.
 The circulation which starts from the right ventricle and ends in the left atrium is called pulmonary
circulation

11. THANK YOU