HEART AND CIRCULATORY SYSTEM (Part-II)

Red blood cells contain a molecule called haemoglobin, which binds and transports oxygen throughout the body. Haemoglobin is made up of four protein chains that each bind an additional ring-shaped chemical structure called heme. Our red blood cells are red because of the heme groups in haemoglobin. In turn, our blood is red because of the millions of red blood cells that it contains.

Red blood cells contain a molecule called haemoglobin, which binds and transports oxygen throughout the body. Haemoglobin is made up of four protein chains that each bind an additional ring-shaped chemical structure called heme. Our red blood cells are red because of the heme groups in haemoglobin. In turn, our blood is red because of the millions of red blood cells that it contains.

Oxygen is carried in the blood either in dissolved form or in association with haemoglobin. However, to calculate the concentration of oxygen transported in the blood, one needs to understand the amount of oxygen carried by each gram of haemoglobin. In a saturated condition, one gram of haemoglobin carries 1.34 ml of oxygen. Normally 100 ml of blood has around 15 gm of haemoglobin in it. Thus, the amount of oxygen carried in 100 ml of pure blood can be calculated as 15 × 1.34 ml = 20 ml.

Polycythaemia refers to an increase in the number of red blood cells in the body. The extra cells cause the blood to be thicker, which increases the risk of other health issues, such as blood clots. Polycythaemia can have different causes, each of which has its own treatment options.

The normal blood pH level in humans is slightly above neutral. In other words, the normal human blood pH level is slightly alkaline. According to medical experts, the normal pH of human blood is 7.35-7.45. Thus, anything above or below 7.35-7.45 would be considered abnormal.

Rh antigen, often called the Rh factor, on the cell membranes of the red blood cells (erythrocytes). The designation Rh is derived from the use of the blood of rhesus monkeys in the basic test for determining the presence of the Rh antigen in human blood.

Blood group ‘O’ is a universal donor because it does not contain any antigen. Therefore, its blood can be offered to all classes of people. On the other hand, due to the presence of both antibodies antibody a and antibody b in the plasma of this class, the blood of any other class of persons cannot be transfused to this class of persons. It is to be noted that the O (O negative) blood group is considered the best donor, as the Rh factor is also absent in it.

Blood group ‘O’ is a universal donor because it does not contain any antigen. Therefore, its blood can be offered to all classes of people. On the other hand, due to the presence of both antibodies antibody a and antibody b in the plasma of this class, the blood of any other class of persons cannot be transfused to this class of persons. It is to be noted that the O (O negative) blood group is considered the best donor, as the Rh factor is also absent in it.

AB blood group people are considered as universal recipients because this blood group has no anti-bodies hence it can receive blood from all groups. AB type blood has no antibodies against type A or type B blood. So a person with AB blood can receive any type blood without the risk of adverse effects. Group AB / Type Rh Positive recipients are group-type compatible with all other blood groups and types.

Haematopoiesis is the process that creates new blood cells within the body. Haematopoiesis occurs primarily within the bone marrow in adults, and within the bone marrow, liver, and spleen in children. Most blood cells are created in bone marrow, the spongy substance found inside a bone's structure. There are two types of marrow, red and yellow; both contain blood vessels and veins that transport nutrients and waste in and out of bones.