The Thymus Gland is very closely associated with the immune system as compared to the endocrine system, despite the fact that it contains glandular tissue and produces several hormones. The Thymus plays an important role in training and development of T-lymphocytes or T cells – a highly important type of white blood cell. T cells defend our body from possibly deadly pathogens such as viruses, fungi and bacteria. It is a part of the immune system and plays a major role in preparing the immunity of our body against the infections and diseases.
The Thymus Gland is located at the upper chest behind the breastbone and between the lungs. It weighs nearly 15 grams at the time of birth and it grows rapidly in the first year after birth. The growth continues till the person attains puberty. Thus, the size of Thymus Gland is largest at the time of puberty and it weighs about 35 grams. There is a gradual shrinking of the thymus after puberty and thus the size decreases, with the disappearance of lymphoid tissue and the appearance of fat and fibrous tissue.
The Thymus Gland is divided into two lobes which are further divided into smaller sub divisions known as lobules. These lobules are covered with connective tissues that support the gland with its fibres. The tissues are divided into two types – an outer zone known as the cortex and an inner zone known as the medulla. Further, the tissues are made up of two types of cells – the reticular cells which are arranged in the form of a loose meshwork and the gaps created are filled in by the other type of cells, lymphocytes.
The main function of the Thymus Gland is the production of the T cells. These T cells are transformed from the white blood cells in the Thymus Gland. It also produces a hormone known as thymosin, which helps in production and development of these cells. These cells are then transported to various lymph glands to act as our body’s immunity against foreign invaders such as bacteria, virus, fungi, parasites etc.
The function of Thymus Gland is mostly accomplished in a newborn and till it attains puberty, thus removal of this organ from an adult hardly has any negative impact on the person. In case, if a child is born without the Thymus Gland, the body has a weaker immune system due to inability to produce T cells to act against the foreign particles. Thus, the person becomes less immune to most of the diseases.
The major disorders of thymus are the thymus hyperplasia which is the inflammation of the Thymus Gland and thymus cancer which is again of two types – thymoma and thymic carcinoma. The cancer cells of thymoma are similar to thymus cells while those of thymic carcinoma are not.