Immune response of older people becomes weak. Name the endocrine gland responsible.Name the hormone secreted by this gland and state its role in maintaining the immune system.

Thymus gland is responsible for the weak immune system in older people. The hormone secreted by this gland is known as thymosin. This hormone promotes the production of antibodies and also increases the production of T – lymphocytes that usually fight with the diseases. In old age due to lack of secretion of thymosin hormone, production of T cells also goes down which causes weaker immune system.