Parathyroid Gland : Functions and Deficiency of Parathyroxine

Endocrines : The glands of the body may be divided into those with an external secretion (exocrine glands) and those with an internal secretion (endocrine glands). Example of exocrine glands are the sweat, Lachrymal and mammary glands which pass their secretion along the ducts to the external surface of the body and the glands of the mouth, stomach, and intestine which pass their secretions along ducts into the alimentary tract. The endocrine or ductless gland on the other hand have no ducts or openings to the exterior.

The secretions are passed directly into the blood stream and transmitted to the tissues.

A hormone is a chemical substance produced by the endocrine glands and their overall function is to regulate the activities of various body organs and their functions. The first hormone was discovered by Bayliss in 1903.

The main endocrine glands in the body are :

Thyroid

Parathyroid

Islets of Langerhans

Adrenal gland

Pituitary and

Sex glands

PARATHYROID GLAND

These are two tiny oval pairs (6mm x 2m) of glands situated at upper and lower poles of lateral lobes of thyroid gland. It secretes the hormone, parathyroxine.

Functions of Parathyroxine

Increases the concentration of organic acid in the bone.

Increases the calcium and phosphorus solubility

Increases the reabsorption of calcium from the bones resulting in increased serum calcium level.

Increases phosphate excretion in the urine.

Increases the reabsorption of calcium from the renal tubules.

Promotes the absorption of calcium and phosphorus from the intestine.

Stimulates the process of lactation in mammary gland.

Deficiency of Parathyroxine

Serum calcium level falls.

Blood reaction is more alkaline owing to excessive loss of CO

2.

Decalcification of bones.

Increase in the heart and respiration rate.

Rise in body temperature.

General mental depression.

Tendency to cataract formation.

Under development of teeth.

Brittleness of nails.

Dryness of skin.

Lowered general resistance.

Nervous irritability.

Twitching of muscles causing

Tetany is a condition, in which there is hyperexcitability of nervous system with intermittent tonic spasms of muscles chiefly of the limbs, face, and back of the neck. When the small muscles of hands are affected, the hand is held in the same position. It is known as

Carpo - Pedal spasms. When the laryngeal muscle are affected laryngeal spasm is seen. If tetany is not treated it may lead to paralysis of respiratory muscle and cardiac arrest. Finally death may occur.