Question

Which of the following contains no b cells but have T cells?

1. blood

2. spleen

3. bone marrow

4.lymph nodes

5. thymus

Answer 1

Answer : Option 5, Thymus.

Lymphocytes are white blood cells that are also one of the body's main types of immune cells.

In our body mainly 2 types of lymphocytes are produced. B lymphocytes and T lymphocytes. Both of this lymphocytes are produced in bone marrow. The development of T lymphocytes happens in Thymus, where as the development of B lymphocytes happens in Bone marrow. So in thymus normal b cells are not present.

But a unique population of B lymphocytes are reside at the cortico-medullary junction of the thymus. It is entirely different from normal B cells, both in terms of their origin and phenotype. So thymus contain T cell but no B cell.

Both T and B lymphocytes, are two types of white blood cell. From this it is clear that both lymphocytes are present in blood. So first option is not correct.

The spleen contains 15–25% of the lymphocytes of our body.

The white pulp of the spleen is characterized by a parenchyma that consists of both lymphocytes (B cells and T cells). Both cells are located in two different areas of the spleen. B cells are located in the lymphoid follicles scattered throughout the organ.

So the second option is also wrong.

Both lymphocytes are present in bone marrow. Also the development of B cells happens inside the bone marrow. In B cell, 'B' indicates its developments place. So third option is also wrong.

Lymph nodes are small glands that filter lymph, the clear fluid that circulates through the lymphatic system. Lymph contains a variety of substances, including proteins, salts, glucose, fats, water, and white blood cells (Both B and T cells). It completely devoid of RBC (Red Blood Cell). So this option is also wrong.