Question

Thymosin stimulates secretion of
A. Milk
B. Erythrocytes
C. T-lymphocytes
D. Melanocytes

Answer 1

Hint: Endocrine system is a system that regulates glands which are present throughout the body. It regulates the body functions. Endocrine system works by releasing hormones from glands. These glands are ductless and hence secretion from these glands enters directly into the bloodstream. These hormones work specifically on different target tissues and control its functions by releasing biochemicals. The human endocrine system includes Hypothalamus, pituitary, pineal gland, thyroid gland, thymus, parathyroid, adrenal gland, pancreas and gonads.

Complete Step by Step Answer:
Thymus is a bilobed structure which is located between the lungs behind the sternum on the ventral side of the aorta. Thymus is functional in infants whereas it is rudant (non-functional) in adults. After puberty, thymus starts degenerating and is eventually replaced by fats. The thymus gland secretes a hormone called thymosin which plays a major role in maturation of T-lymphocytes. The matured lymphocytes travel to the lymph nodes and help in fighting against diseases. These lymphocytes provide cell-mediated immunity. As thymosin produces antibodies as well, it provides humoral immunity. During old age, people start becoming weak because the thymus becomes non-functional.



Note: Thymus gland disorders include Myasthenia gravis, pure red aplasia and hypogammaglobulinemia. During Myasthenia gravis, muscles become weak due to abnormal enlargement of thymus that destroys the antibodies produced by thymus. Pure red aplasia occurs when there is a tumor in the thymus. During this condition a person's immune cells attack their own blood forming cells. Enough antibodies are not formed during hypogammaglobulinemia. Thymus related cancers are malignant in most of the cases and can be treated by surgeries or chemotherapy.