Thymus Gland
The thymus is a gland that participates in the regulation of the body’s immune defense. It is considered a primary lymphoid organ.
Location of the thymus
The thymus is located in the chest, between the lungs and the front of the heart.
It changes size according to the stages of life. From birth to adolescence, the thymus reaches up to 40 grams.
From then on, it begins to decrease in size until the elderly phase. However, even with its decrease, the functions are not lost.
Function
The main function of the thymus is the maturation of T lymphocytes .
Immature lymphocytes are produced in the bone marrow and migrate to the thymus, where they mature and transform into T lymphocytes. From the thymus, they enter the bloodstream and reach the lymphoid tissues .
The thymus only releases T lymphocytes after recognizing that they will not react against the body’s natural proteins or antigens . Thus, it selects the T lymphocytes to be released into the bloodstream.
This function of the thymus ensures the correct functioning of the immune system . When there are few T lymphocytes in the body, the chances of acquiring diseases increase.
The thymus is also responsible for producing the hormone thymosin , which stimulates the maturation of T lymphocytes.
Anatomy and Histology
The thymus is divided into two joined lobes and numerous lobules of different shapes and sizes. The two lobes often vary in size and shape. It is common for the right lobe to be smaller than the left lobe.
The thymus is covered by a capsule of connective tissue .
Each lobe of the thymus has two parts:
- Cortex : Peripheral region with a large number of lymphocytes. It is the area of intense lymphocyte production;
- Medulla : Central region with few mature lymphocytes.
The cells that make up the thymus are largely lymphocytes, but there are also reticular cells and macrophages .
Lymphocytes that are not selected by the thymus die and are destroyed by macrophages.
Histologically, it is possible to observe Hassall’s corpuscles, which are clusters of epithelial cells organized around a central point.
Read also:
- Glands of the human body
- Endocrine glands
- Organs of the human body
- Lymphatic system
- Endocrine system
Curiosities
- The term thymus derives from the Greek Thymus and means vital energy.
- In ancient times, it was believed that a person’s soul was kept inside the thymus.
- The thymus was the last of the body’s important organs to have its functions revealed.