Anatomy and Physiology II Practice Test 2025 - Free Anatomy Practice Questions and Study Guide

The thymus gland produces thymosin, which is a hormone that plays a crucial role in the immune system. Thymosin is essential for the maturation of T-cells, a type of white blood cell that is vital for adaptive immunity. This hormone helps in the development and differentiation of T-lymphocytes from precursor cells, enabling them to respond effectively to pathogens and infections.

Thymosin's function is particularly important during childhood and adolescence when the thymus gland is most active. As individuals age, the thymus shrinks, and thymosin production diminishes, which is one reason why the immune response can become less robust in older adults.

Insulin, produced by the pancreas, regulates blood sugar levels; cortisol, produced by the adrenal glands, is involved in stress response and metabolism; and adrenaline, also produced by the adrenal glands, is associated with the body's fight-or-flight response. These hormones have different functions and originate from different glands, making thymosin distinct in its role related specifically to immune system development.