Question

Which gland decreases in size with increasing age?
(a) Thyroid
(b) Adrenal
(c)Thymus
(d) Pituitary

Answer 1

This is a specialized primary lymphoid organ of the immune system. This gland remains present in the chest, directly behind the breastbone or sternum, and in front of the heart in the area between the lungs.

Complete answer:
The thymus gland is large in infants about 5 cm in length, 4 cm in breadth, and about 6 mm in thickness, but after infancy, it grows and reaches its maximum size during puberty i.e., maximum weight 20 to 37 grams by the time of puberty. After puberty, the thymus gland shrinks and becomes largely replaced with fat or tiny islands of fatty tissue. The gland is very small in elderly people, by the age of 75 years, the thymus weighs only 6 grams, but can sometimes atrophy prematurely in response to severe stress. "Thymic involution" is the term used to describe the atrophy of the thymus gland with age.

Additional Information:
-The thymus is found within the upper front, a part of the chest, within the anterior superior mediastinum, behind the sternum, and ahead of the guts.
-It is formed from two lobes, each consisting of a central medulla and an outer cortex, surrounded by a capsule.
-A number of various cell types are present within the thymus.
Epithelial cells: The cells that line body surfaces and cavities
Kulchitsky cells: The cells that are the hormone-producing cells of the thymus or neuroendocrine cells.
Thymocytes: The cells that become mature T lymphocytes.
-The thymus is additionally home to some macrophages. Macrophages are known as the "garbage trucks" of the immune system because they eat foreign matter.
-Dendritic cells and a couple of B lymphocytes that produce antibodies also reside within the thymus. -The thymus is extremely active from before birth until puberty, and it functions as both a lymphatic organ and an endocrine organ.
-T cells are liable for directly killing infected cells.
-T cells are a part of the adaptive system, during which each T cell has been trained to acknowledge a specific antigen. When exposed to a foreign cell, cytotoxic T cells lock onto the cell and kill it with assistance from the helper and regulatory T cells.

So, the correct answer is,’Thymus’.

Note:
-The thymus is formed from two lobes, each consisting of a central medulla and an outer cortex, surrounded by a capsule.
-Macrophages found in the thymus are known as the "garbage trucks" of the immune system because they eat foreign matter.
-The thymus is extremely active from before birth until puberty, and it functions as both a lymphatic organ and an endocrine organ.
-Dendritic cells and a couple of B lymphocytes that produce antibodies also reside within the thymus.