Basic info of the heart...inside and outside
The heart has four rooms, two on the right side and two on the left side. The upper rooms are called atrium and the lower ones are called ventricles. Thus, there is a right atrium (RA), a left atrium (LA), a right ventricle (RV) and a left ventricle (LV).
Two big tubes coming out of the lower rooms on either side. These are called Aorta and Pulmonary Artery (PA). The aorta carries oxygen-rich blood from the left ventricle (LV) to the whole body. The pulmonary artery carries oxygen-poor blood from the right ventricle (RV) to the lungs to get oxygenated.
For circulation to be proper, blood is meant to move in only one direction. In a forward direction. The heart valves help on this front by allowing blood to flow forwards and preventing it from coming backwards.
Thus, all the impure (less oxygen, more carbon dioxide) blood from the upper and lower parts of the body comes through the superior and inferior vena cava respectively to the right atrium. From there across the tricuspid valve, it goes to the RV. From the RV, the PA carries blood to the the lungs across the pulmonary valve. From the lungs,all the pure (more oxygen, less carbon dioxide) blood comes to the LA. From the LA, it goes to the LV across the mitral valve. Finally, from the LV, blood is sent to the aorta across the aortic valve.
Coronaries:
From the aorta at its beginning, two tubes arise. These tubes that carry oxygen rich blood are called arteries. Arteries of the heart are called 'Coronaries'.
There's one left main coronary artery (LM) and one right coronary artery (RCA).
The left main coronary divides into two branches - Left anterior descending (LAD) and Circumflex (Cx).
LAD has branches called Diagonals (D1,D2,D3..) and Septals (1st septal, 2nd septal...).
Cx has branches called Obtuse marginals (OM1,OM2, OM3)
RCA has branches called Posterior Descending Artery (PDA) and Posterior Left Ventricular Artery (PLV). RCA also important branches supplying blood to two important points in the electrical circuit of the heart (SA nodal artery & AV nodal artery)
