The heart is divided into four chambers. The top chamber with comparatively thinner wall are called auricles. The two lower chambers with thick muscular wall are called ventricles.
- The right auricle receives carbon dioxide-rich blood from the various parts of the body. The right ventricle pumps the blood to the lungs, where carbon dioxide is removed and oxygen is absorbed.
- The left auricle receives oxygen-rich blood as it comes back to the heart from the lungs. The left ventricle pumps this blood to the rest of the body. The right side of the heart is completely separated from the left side with the help of a partition called septum, so that the two types of blood do not mix.
- The heart has a number of valves that allow the blood to flow in one direction only. Figure shows the complete circulatory system in the body. The blood enters the right side of the heart and is pumped to the lungs where it gives up carbon dioxide and picks up oxygen. This oxygen- rich blood travels back to the left side of heart. It is again send to all other parts of the body and the process is repeated again and again.
Information related to the blood:
| Blood group of Doner |
Blood group of Receptor |
| A |
B |
AB |
O |
| A |
✓ |
X |
✓ |
X |
| B |
X |
✓ |
✓ |
X |
| AB |
✓ |
X |
✓ |
X |
| O |
✓ |
✓ |
✓ |
✓ |
NOTE:
Symbol (✓) Means blood can be given Symbol (x) means blood cannot be given. The person of group AB can receive blood from any one.
The person of group O can give blood to any person. In this way group AB is the universal receptor while group O is the universal donor.
