Thymus Questions in English

(D) The $Thymus$ gland is a lobular structure located between the lungs behind the sternum on the ventral side of the aorta.
It plays a major role in the development of the immune system.
This gland secretes the peptide hormone $Thymosin$,which promotes the differentiation of $T$-lymphocytes,providing cell-mediated immunity.
In addition,$Thymosin$ also promotes the production of antibodies to provide humoral immunity.
As a person ages,the $Thymus$ undergoes gradual degeneration (atrophy),resulting in a decreased production of $Thymosin$.
Consequently,the immune responses of older individuals become weaker.

(D) The Thymus gland is a lobular structure located between the lungs behind the sternum on the ventral side of the aorta,which is in the upper part of the thorax ($i$ is correct).
It is a bilobed structure,not four-lobed ($ii$ is incorrect).
It is a prominent gland at birth but gradually atrophies with age,meaning it does not remain active throughout life ($iii$ is incorrect).
Due to its atrophy in adults,it is often referred to as a temporary gland ($iv$ is correct).
The Thymus plays a major role in the development of the immune system by secreting thymosins,which promote the differentiation of $T$-lymphocytes,providing cell-mediated immunity,not humoral immunity ($v$ is incorrect).
Therefore,only statements $i$ and $iv$ are correct. However,based on the provided options,the most appropriate choice reflecting the anatomical location and the temporary nature of the gland is $D$.

(C) . Loss of cell-mediated immunity.
Damage to the thymus in a child may lead to the loss of cell-mediated immunity. The thymus is the primary lymphoid organ responsible for the development and maturation of $T$-lymphocytes ($T$-cells). Since $T$-cells are essential for orchestrating cell-mediated immune responses,their absence or dysfunction due to thymic damage significantly impairs this branch of the immune system.