The Heart
HEART
→ Blood flows in a double circulation, through the lungs and throughout the body.
→ The heart is a muscle the size of a clenched fist.
→ It contains 4 chambers, right atrium, right ventricle, left atrium and left ventricle.
ATRIA
→ singular: atria
→ 2 upper chambers - right and left atrium.
→ Receive blood from veins - pulmonary vein and vena cava.
→ Have thin walls, as they only force blood into ventricles and high pressure unrequired.
VENTRICLES
→ Larger lower chambers - right and left ventricle.
→ Have thick, muscular walls, since high pressure is required to pump blood out of the heart.
→ Left ventricle is thicker as it needs to pump blood to the whole body.
→ Right ventricle is thinner as it only pumps blood to lungs.
MEDIAN SEPTUM
→ Muscular wall in the middle of the heart that separates left and right ventricle.
→ Prevents mixing of oxygenated and deoxygenated blood.
→ Mixing of blood will result in lesser oxygen transported to the rest of the body.
The Heart
★ HOLE IN HEART
→ Hole in median septum leads to mixing of oxygenated and deoxygenated blood.
→ Since pressure on left side is higher, blood will flow from left atrium to right atrium.
→ Less oxygen is transported to the rest of the body.
→ Causes patient to suffer from shortness of breath, fatigue and in serious cases, heart failure and may require surgery.
The Heart
★ DEOXYGENATED BLOOD
→ Right atrium, Right ventricle
→ Superior and Inferior Vena Cava - brings blood from the rest of the body.
→ Pulmonary Artery - only artery which is deoxygenated, brings blood to lungs to be filled with oxygen.
★ OXYGENATED BLOOD
→ Left Atrium, Left Ventricle
→ Aorta - brings blood from heart to the rest of the body.
→ Pulmonary Veins - only vein which is oxygenated, brings blood from lungs to the heart.
★ VALVES
→ Function: Prevents backflow of blood in blood vessels.
→ Tricuspid Valve - Has 3 flaps, prevent backflow of blood from right ventricle to right atrium.
→ Bicuspid Valve - Has 2 flaps, prevent backflow of blood from left ventricle to left atrium.
→ Aortic Valve(SLV in aorta) - Prevents backflow of blood from aorta to left ventricle.
→ Pulmonary Valve(SLV in pulmonary artery) - Prevents backflow of blood from pulmonary artery to right ventricle.
The Heart