Introduction: The parathyroid gland is a small endocrine gland that appears as small oval-shaped bodies with a brown color. It is called the parathyroid gland due to its location closely with the thyroid gland .
Materials and Methods: The study used six adult males of Felis catus from the local markets in Baghdad. Formalin (10%) was used to fix the samples for preparing all specimens to conduct histological study. They were passed in an alcohol ascending series 70, 80, 90 and 100% and cleared by xylene. Masson's Trichrome stain (MTc), Haris hematoxlin and Eosin stain (H&E), Periodic Acid Schiff stain (PAS), were used to stain the gained sections.
Results: The current study observed the presence of two pairs of parathyroid glands in Felis catus animal, which are in contact with the thyroid gland, occupying an apical peripheral site and a lateral peripheral site, and located within the thyroid gland tissue embedded in its substance. Moreover, the gland appears as lobes consist of 2-4 with oval or irregular in shape and surrounded with a thin capsule. A capsule of connective tissue surrounds the parathyroid gland in F. catus is an extension of the capsule of the thyroid gland consisting of collagen, elastic and reticular fibers, nuclei of smooth muscle fibers, blood vessels, and nerves. The septa are extended from the capsule which divides the gland into lobules, the parathyroid gland tissue has three types of cells represented by chief cells, which are the most common cells , while the other two types are Oxiphyl cells and water-clear cells .
Conclusion: The current study Felis catus, observed the presence of two pairs of parathyroid glands in Felis catus animal, which are in contact with the thyroid gland. Moreover, the gland appears as lobes consist of 2-4 with oval or irregular in shape and surrounded with a thin capsule, and their internal histological structure consists of three cell kinds: chief, Oxphill, and water clear cells.