Hemoglobin is made up of four protein molecules (globulin chains) that are connected together. The normal adult hemoglobin (Hbg) molecule contains two alpha-globulin chains and two beta-globulin chains. In fetuses and infants, beta chains are not common and the hemoglobin molecule is made up of two alpha chains and two gamma chains. As the infant grows, the gamma chains are gradually replaced by beta chains, forming the adult hemoglobin structure.Hemoglobin also plays an important role in maintaining the shape of the red blood cells. In their natural shape, red blood cells are round with narrow centers resembling a donut without a hole in the middle. Abnormal hemoglobin structure can, therefore, disrupt the shape of red blood cells and impede their function and flow through blood vessels.Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs.
The normal ranges for hemoglobin depend on the age and, beginning in adolescence, the gender of the person. The normal ranges are:
Newborns: 17 to 22 gm/dL
One (1) week of age: 15 to 20 gm/dL
One (1) month of age: 11 to 15gm/dL
Children: 11 to 13 gm/dL
Adult males: 14 to 18 gm/dL
Adult women: 12 to 16 gm/dL
Men after middle age: 12.4 to 14.9 gm/dL
Women after middle age: 11.7 to 13.8 gm/dL
Each globulin chain contains an important central structure called the heme molecule. Embedded within the heme molecule is iron that is vital in transporting oxygen and carbon dioxide in our blood. The iron contained in hemoglobin is also responsible for the red color of blood.