Transcript
PARATHYROID GLAND
PARATHYROID GLAND
• Four small glands
• Located behind the thyroid gland, one at each end of the upper and lower poles
• Can also be found in the mediastinum lying beside the thymus
• Usually embedded in the thyroid capsule
• Derived from the pharyngeal pouches
PARATHYROID GLANDS
• Contained within connective capsuleCapsules send septa into gland, merge with
reticular fibers that support secretory cells
• Consists of 2 cell typesChief CellsOxyphil Cells
PARATHYROID GLAND
TYPE OF CELLS
• Chief cells
• Oxyphil Cells
CHIEF CELLS
• Small polygonal cells with round nuclei
• Arranged in cords presenting whorl – like appearance
• Cytoplasm is filled with irregularly shaped granules
• Occasionally occur as clusters
• Synthesis and secretion of parathyroid hormone (parathormone)
CHIEF CELLS
RED - Chief Cells
OXYPHIL CELLS
• “Hürthle cells”
• Larger than chief cells
• Found singly or in small groups
• Less numerous than chief cells
OXYPHIL CELLS
RED – Oxyphil cells
PARATHYROID HORMONE
• Increases blood calciumIncreasing bone resorptionDecreasing renal excretionIncrease gastrointestinal uptake of calcium
Stimulating Vitamin D
Reduces blood phosphate
PARATHYROID PRINCIPAL CELLS
PARATHYROID PRINCIPAL CELLS
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