Question

Name the primary lymphoid organs.

Answer 1

bone marrow and thymus gland

Answer 2

Primary Lymphoid Organs

The Organs where lymphocytes originate and mature to become antigen sensitive, ex - bone marrow and thymus, are called primary lymphoidil6organ

• Bone Marrow

Bone marrow It is the primary lymphoid organ where all blood cells including lymphocytes originate.

Bone marrow provides the micro-environment for the development and maturation of B-lymphocytes.

• Thymus

Thymus is a lobed organ located near the heart and beneath the breastbone.

It is quite large at the time of birth but reduces with age.

It provides the micro-environment for the development and maturation of T-lymphocytes.

Secondary Lymphoid Organs

The Organs where lymphocytes interact with the antigen and proliferate to become effector cells, ex - spleen, lymph nodes.

• Spleen

It is a large bean-shaped organ and contains lymphocytes and phagocytes.

It acts as a filter of the blood by trapping blood-borne microorganisms.

It has a large reservoir of erythrocytes. b. Lymph nodes .

They trap the microorganisms or other antigens that enter the lymph and tissue fluid.

Antigens trapped in the lymph nodes activate the lymphocytes and produce an immune response.

• Lymph nodes

These are small solid structures present at different points along the lymphatic system.

They trap the microorganisms or other antigens that enter the lymph and tissue fluid.