IMMUNOLOGY

OVERVIEW OF THE IMMUNE SYSTEM

LYMPHATIC AND IMMUNE SYSTEM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which of the following is involved with the development of T lymphocytes in the fetus and infants?
A
adenoids
B
spleen
C
tonsils
D
thymus
Explanation: 

Detailed explanation-1: -Lymphocytes of the B series develop in the liver by 9 weeks’ gestation and are present in the blood and spleen by 12 weeks. T lymphocytes start to leave the thymus from about 14 weeks’ gestation and subsequently cells with helper and suppressor phenotypes are present in the spleen.

Detailed explanation-2: -T lymphocytes develop from a common lymphoid progenitor in the bone marrow that also gives rise to B lymphocytes, but those progeny destined to give rise to T cells leave the bone marrow and migrate to the thymus (see Fig. 7.2). This is the reason they are called thymus-dependent (T) lymphocytes or T cells.

Detailed explanation-3: -thymus: A ductless gland consisting mainly of primary lymphatic tissue that is the site of lymphocyte maturation and selection.

Detailed explanation-4: -T cells originate in the bone marrow and mature in the thymus. In the thymus, T cells multiply and differentiate into helper, regulatory, or cytotoxic T cells or become memory T cells.

There is 1 question to complete.