Question

Describe lymph nodes. What are its functions?

Answer 1

Lymph nodes are specialized masses of tissue that are situated along lymphatic system pathways. These structures filter lymph fluid before returning it to the blood. Lymph nodes, lymph vessels, and other lymphatic organs help to prevent fluid build-up in tissues, defend against infection, and maintain normal blood volume and pressure in the body. With the exception of the central nervous system (CNS), lymph nodes may be found in every area of the body.

Functions

Lymph nodes serve two major functions in the body. They filter lymph and assist the immune system in building an immune response.

Lymph nodes house lymphocytes which are immune system cells that originate from bone marrow stem cells. B cells and T cells are lymphocytes found in lymph nodes and lymph tissues. When B-cell lymphocytes become activated due to the presence of a particular antigen, they create antibodies that are specific to that specific antigen. T-cell lymphocytes are responsible for cell mediated immunity and participate in the destruction of pathogens as well.

Lymph nodes filter lymph of harmful pathogens such as bacteria and viruses. The nodes also filter out cellular waste, dead cells, and cancerous cells. The filtered lymph from all areas of the body is eventually returned to the blood through a blood vessel near the heart. Returning this fluid to the blood prevents edema or the excess accumulation of fluid around tissues. In cases of infection, lymph nodes release lymphocytes into the blood stream to aid in the identification and destruction of pathogens.