The heart is a pumping organ located in the chest that continuously circulates blood through the body. It has four chambers - the two upper chambers are the atria and the two lower chambers are the ventricles. The septum separates the chambers and prevents mixing of oxygenated and deoxygenated blood. Blood flows from the right atrium to the right ventricle then to the lungs, returns oxygenated to the left atrium and left ventricle, then is pumped through the aorta to the rest of the body in a continuous cycle.

1. Circulatory system of man Includes Heart,Blood and Blood vessels

2. Location of Heart

3. Heart is a pumping organ that keeps the blood continuously moving in the blood vessels It is a blunt conical organ of about 12cm long and 9 cm broad. Its narrow apex is pointed downward and to the left. Heart is enclosed in a doubled walled sac, called pericardium

5. Human heart consists of four chambers. The two upper chambers are called atria (or auricles) and the two lower ones the ventricle. Two auricles are separated by an inter atrial septum. Two ventricles are separated by an inter ventricular septum. Septum prevents the mixing of oxygenated blood and deoxygenated blood. Chambers of Heart

6. The right auricle and right ventricle guarded by tricuspid valves. The left atrium and left ventricle are guarded by bicuspid (Mitral) valve. Valves allows only unidirectional flow of blood. Semi lunar valves is present at the base of pulmonary artery. Valves of the heart

7. Ventricles have thick walled than atria. because ventricles have to pump out the blood with force to the different parts of the body. Left ventricles are far thicker walled than right ventricles as it is pumping the blood to different parts of the body a right ventricle is only up to lungs Ventricles

8. From right atrium the deoxygenated blood enters the right ventricle through tricuspid valves. From right ventricle the deoxygenated bloods pumped out through pulmonary artery to lungs for oxygenation. Oxygenated blood from left atrium enters the left ventricles through bicuspid valve. From left ventricle, the oxygenated blood is pumped out into aorta. Aorta is the largest artery which takes the blood to the body. Flow of Blood

9. Vena Cava Right Atrium Right Ventricle Pulmonary artery Lungs Pulmonary vein Left atrium Left Ventricle Aorta the largest artery tissues Flow of Blood in the body