Question

Which one of the following glands is correctly matched with the accompanying description?
A. Thyroid - Hyperactivity in young children causes cretinism.
B. Thymus - Start undergoing atrophy after puberty.
C. Parathyroid - secretes parathormone which promotes movement of sodium ions from blood into bones during calcification.
D. Pancreas - Delta cells of islets of langerhans secrete a hormone which stimulates glycolysis in the liver.

Answer 1

Hint: Endocrine glands are ductless glands as they lack ducts. The secretions are poured directly into the blood. Hormones are the secretions of endocrine glands. Hormones are non-nutrient chemicals produced in trace amounts and act as intercellular messengers. Invertebrates have a very small number of hormones with a simple endocrine system whereas vertebrates produce hormones in large amounts for the purpose of coordination. The human endocrine system includes pituitary gland, pineal gland, adrenal gland, thymus gland, pancreas, parathyroid, and gonads.

Complete Step by Step Answer:
The thyroid gland has two lobes which are present on either side of the trachea. The two lobes are interconnected with the help of isthmus which is a thin flap of connective tissue. The gland is composed of follicle and stromal tissue. Each follicular cell secretes two hormones called thyroxine and triiodothyronine. Deficiency of thyroxine can lead to hypothyroidism, which is enlargement of the thyroid called goitre, whereas high levels of thyroxine can cause hyperthyroidism which affects body physiology.

Thymus is a lobular structure that is present between lungs behind the sternum on the ventral side of the aorta. It plays an important role in building up the immunity of a person. This gland secretes a hormone called thymosins. Thymosins help in differentiation of T-lymphocytes . It promotes production of antibodies and thus provides humoral immunity. As we grow older, thymus start degenerating which results in the decreased amount of thymosin and thus it adversely affects immunity. The person starts undergoing atrophy; that is becoming weak.

Parathyroid glands are four in number in human beings and are present on the back side of the thyroid gland. Parathyroid gland secretes parathyroid hormone (PTH) that increases the calcium level in the blood.

Pancreas is composed of islets of langerhans. The two main types of cells are alpha cells and beta cells. Alpha cells promote glycogenesis whereas beta cells promote glycolysis.

Hence the correct option is B:- Thymus - start undergoing atrophy after puberty.



Note: Specific proteins called hormone receptors are present at the target tissue of the hormone. The hormone targets the tissue by binding with the hormone receptors.