PARATHYROID GLAND BY: DR RAJ SHARMA NOIDA INTERNATIONAL UNIVERSITY - - PowerPoint PPT Presentation

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Nov 15, 2023 267 likes •474 views

PARATHYROID GLAND BY: DR RAJ SHARMA NOIDA INTERNATIONAL UNIVERSITY OVERVIEW OF THYROID GLAND Thyroid Essentials: regulates your metabolism Butterfly-shaped gland wrapped around trachea The two main thyroid hormones are T3 and T4.

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BY: DR RAJ SHARMA NOIDA INTERNATIONAL UNIVERSITY

PARATHYROID GLAND

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OVERVIEW OF THYROID GLAND

Thyroid Essentials:

 regulates your metabolism  Butterfly-shaped gland wrapped around trachea  The two main thyroid hormones are T3 and T4.  Appear on front of the neck

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Thyroid disorders are common, and

they include goiters, hyperthyroidism, and hypothyroidism.

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PARATHYROID GLAND

 Human being have four parathyroid glands  Situated at back surface of the thyroid gland  Located in neck  Very small in size  Measures- •6mm long •3mm wide & •2mm thick  Dark brown in colour

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DIAGRAMATIC VIEW :

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FUNCTIONS OF PARATHYROID GLAND

 main function : produce and

secrete a hormone called PTH (parathyroid hormone)

 raises blood calcium level

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HISTOLOGY (microscopic study)

 made up of chief cells and oxyphil cells

1.CHIEF CELLS: secretes PTH (parathyroid hormone) 2.OXYPHIL CELLS: •degenerates chief cells

may secrete PTH during

pathological condition called parathyroid adonema (a small tumour of PT gland)

 gland inc. In size due to production of PTH in excess.

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SOURCE OF SECRETION

secreted by the

chief cells of the parathyroid gland

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PARATHYROID HORMONE

 regulates calcium, magnesium,

phosphorus levels in blood.

Main function is to increase Calcium

levels when they are low

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ROLE OF ‘Ca’ IN OUR BODY

 Bone&teeeth formation  Neuronal activity  Skeletal muscle activity  Cardiac activity  Smooth muscle activity  Secretory activity  Cell division & growth  Coagulation of blood

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CHEMISTRY

Parathyroid hormone is protein in nature Having 84amino acids Having molecular weight :- 9,500 Da

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SYNTHESIS

 Synthesised from precursor called pre-pro-PTH containing 115 amino acids.

PRE-PARATHYROID HORMONE ⬇ PRO-PARATHYROID HORMONE ⬇ PARATHYROID HORMONE

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PROCESS OF SYNTHESIS OF PTH

1. pre-PTH hormone (115 amino acids) enters

the endoplasmic reticulum of the chief cells

f PT gland.
2. Then there,it is converted into a Pro-

hormone called pro-PT hormone .

3. Lastly, pro-PTH enters the golgi

apparatus,and converted into PARATHYROID HORMONE.

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ACTIONS OF PTH ON BLOOD ‘CA’ LEVEL

 Primary action of parathyroid hormone is to

maintain the blood calcium level.

 PTH maintains blood CA level by :-  Resorption of Ca from bones  Reabsorption of Ca from the renal tubules

(kidney)

 Absorption of Ca from intestine

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ROLE OF PTH IN THE ACTIVATION OF VITAMIN D

 Vitamin D is very essential for calcium

absorption from the intestine.

 But vitamin D itself is not an active substance.  So, PTH is the one who is enabling the kidney to

produce Vitamin D which inturn goes to intestine and stimulates more absorption of Calcium.

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BLOOD LEVEL OF CALCIUM

 PTH secretion is inversely proportional to blood

calcium level.

 ⬆ in blood calcium level ⬇ PTH secretion.  CONDITIONS WHEN PTH SECRETION DECREASES:-

⭐ excess quantities of calcium in diet. ⭐ increase vitamin D in diet. ⭐ increased releasing of calcium from the bones, caused by factor such as bone diseases.

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PARATHYROID DISORDERS

 HYPERPARATHYROIDISM

: increased PTH levels in blood 🔺 results to :- HYPERCALCEMIA i.e too much calcium in the blood.

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 HYPOPARATHYROIDISM

: decreased secretion of PARATHYROID HORMONE. : results to HYPOCALCEMIA i.e too little calcium in the blood.

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