The heart

Position of the heart The heart located in the mediastinum between the two lungs

The heart consist of : Apex >> located at the left 5th intercostal space about 9cm away from midline (left ventricle) Base(left atrium)

The surfaces of the heart 1.Anterior surface of the heart (sternocostal) -formed by : 1.Right atrium 2.Right ventricle

2.Inferior surface of the heart (diaphragmatic surface) -consist of right and left ventricles -below the inferior surface there is the diaphragm

3.Posterior surface (the base of the heart) -consist of left atrium

Chambers of the herat Right atrium and right ventricle Left atrium and left ventricle

Blood circulation : The blood circulation starts in right atrium 1.Right atrium receives blood from superior vena cava (upper half of the body) and inferior vena cava (lower half of the body) The blood inflow from the right atrium to right ventricle through tricuspid valve (atrioventricular valve)

Outflow part should be smooth The inflow part should be rough

2.Then the blood (deoxygenated)go out from the right ventricle through pulmonary valve (semilunar valve) to pulmonary trunk

3.the pulmonary trunk consist of right and left pulmonary arteries and the deoxygenated blood go to the lung In the lung the blood reoxygenated

4.oxygenated blood back from lung to the left atrium through four pulmonary veins

5. the oxygenated blood flow from left atrium to left ventricle through BICUSPID VALVE(mitral valve) Here also the inflow should be rough and out flow should be smooth 6.The oxygenated blood go out from left ventricle through aortic valve (semilunar valve )to aorta

7. the oxygenated blood reach to the aorta The aorta consist of three parts: 1.ascending part >> the coronary arteries branched from it 2.aortic arch >> consist of three branches 3. descending part

Aortic arch component: 1.left subclavian artery >> send the blood to the upper limb 2.left carotid artery >> send the blood to the head and neck and brain 3.brachiosphelic trunk >> divided to right subclavian artery and right carotid artery

Fosa ovale The two atriums separated by interatrial septum the fosa ovale(oval depression ) located on the interatrial septum The embryo was not have developed pulmonary circulation ,,so this dipression was opened and we called it foramen ovale When birth the foramen ovale normally closed

The right ventricle and left ventricle separated by INTERVENTRICLE SEPTUM The left ventricle is THREE TIMES THICKER than the right ventricle because it has oxygenated blood so the pressure will be higher