A histological study on the prenatal development of the parathyroid gland of Guinea pig with relation to bone formation.

Abstract

Parathyroid gland had a great importance in keeping of bone mineralization via the action of parathyroid hormone in maintaining the balance of serum calcium level. This study aimed to demonstrate the developmental histological structure of parathyroid gland and bone during prenatal life. The current study was done on twenty-nine Guinea pig embryos. Samples were collected from parathyroid gland and bone of different ages. The parathyroid gland of twentyfive embryonic days (ED) was originated from third pharyngeal pouch as endodermal thickening from the wall of pouch then at 27 ED appeared as a few polyhedral cells. At 30 ED, parathyroid gland appeared as single pair small condensation of cells close to trachea, thyroid gland, and thymus. At 65 ED, the cells of parathyroid gland showed different cytoplasmic changes according to hormone secretion. At early prenatal stage, femur and vertebrae composed of both cartilage and bone. At 65 ED, femur became formed of spongy bone. While ribs were consisted of hyaline cartilage only at the early prenatal stage, then became ossified at late prenatal stage, 65 ED. Bone Development Hyaline cartilage Parathyroid gland