Which one of the following four gland is correctly matched with the accompanying description?
(a) Thyroid - Hyperactivity in young children causes cretinism
(b) Thymus - Starts undergoing atrophy after puberty
(c) Parathyroid - Secretes para-thormone, which promotes movement of calcium ions from blood into bones during calcification
(d) Pancreas - Delta cells of the 'islets of Langerhans' secrete a hormone, which stimulates glycolysis in liver
(b) Thymus - Starts undergoing atrophy after puberty
Explanation:
The thymus is an organ located in the upper anterior portion of the chest cavity just behind the sternum. The thymus continues to grow between birth and puberty and then begins to atrophy. Proportional to thymic size, thymic activity is most active before puberty. Upon atrophy, the size and activity are dramatically reduced, and the organ is primarily replaced with fat. The atrophy is due to the increased circulating level of sex hormones, and chemical or physical castration of an adult result in the thymus increasing in size and activity.