Lymphoid Organs
It is worthwhile to know our lymphoid organs because just like the other parts in our body they too have a great role. The lymphoid organs function in our immunity.
They are our body’s defense network by producing, maturing and housing lymphocytes (white blood cells) to fight infection and diseases.
A. The Lymph Nodes
– the size of the nodes varies from 1 to 10 mm or more depending on the inflammatory process occurring within the region of drainage
– they are widely distributed throughout the body such as in
1. Neck
2 Axillary
3. Femoral
4. Popliteal area
– in cases of infections, the lymph nodes in the area are inflamed so it makes easy to detect the site of infection
B. Spleen
The functions of the spleen are the following:
1. Phagocytosis of effete red cells, cellular debris, white cells, platelets and particulate matters by macrophages
2. In the newborns, together with the liver, the spleen is an active hematopoietic organ until the bone marrow takes over
3. The spleen serves as a circulatory reserve in shock due to hemorrhage or violent exercise
C. The Thymus
– this is a central lymphoid organ which is very active in the early stages of life
– important in the development and maintenance of the peripheral lymphoid tissue which includes the spleen and the lymph nodes
– the following are the functions of the thymus
1. At a critical period of life, the bone marrow stem cells which are the lymphocyte precursors circulate in the blood stream and are converted by the thymus into lymphocytes
2. The thymus gland helps in rendering the lymphocytes attain its immunologic competence
3. A humoral factor secreted by the thymus stimulates lymphopoiesis
4. In the adults, it supplies the lymphoid system with fresh uncommitted lymphocytes which can react to new antigens
The absence of the thymus gland results in:
1. Lymphoid aplasia
2. Lymphocytopenia
3. Cellular immunity deficiency thus resulting to infections and death