endocrine glands

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Dr. Waqas Nawaz PMAS arid agriculture university rawalpindi

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  • 1. Endocrine Glands Waqas Nawaz11-arid-975 Group A-1

2. Endocrine Glands:Endocrine glands are ductless organs that secretespecial substances termed HORMONES.These hormones are released into circulatory systemand transported to distant receptor organ.Hormones are produced by parenchymal cells,whichcan be found as single,aggregate or organized asendocrine glands. 3. Glands of Endocrine System: Pituitary Gland Pineal Gland Thyroid Gland Parathyroid Glands Adrenal Gland Pancreas Gonads 4. Pituitary GlandCalled Master gland of the body.Plays major regulatory role in entire endocrinesystem. 5. Location:Situated at the base of skull.Suspended below diencephalon,in the hypophysealfossa of sphenoid bone.Connected to hypothalamus by pituitary stalk. 6. Morphology:Pituitary gland is an un-paired organ.Has size only of pea. 7. Anatomy of Pituitary Gland: Anatomically pituitary gland is made up of following 3 parts.. Adenohypophysis (anterior pituitary) Neurohypophysis (posterior pituitary) Intermediate lobe 8. Adenohypophysis:Consists of endocrine cells, numerous blood vessels& very few nerve fibers.The pituitary stalk contains a special portalsystem,organised in same manner as portal venoussystem in liver,with two capillary networks followingeach other. 9. Blood supply to adenohypophysis:Vessels from first capillary network convey blood toanterior pituitary.While second capillary system surrounds the hormoneproducing cells. 10. Hormones of adenohypophysis:Hormone Effect SomatotropinGrowth via secretion of IGF-I Thyroid stimulatin hormone (TSH)Secretion of thyroid hormone Adenocorticotopic Hormone (ACTH)Secretion of glucocorticoids and androgens Prolactin (PRL) Production of milk Gonadotropin:-Production and maturation of spermatozoa Follicle stimulating hormone (FSH)and oocyte. Luteinzing hormone (LH) Secretion of sex hormone 11. Neurohypophysis:Second part of pituitary gland.It is a part of central nervous system. 12. Location:Located caudal to adenohypophysis.It is a neural outgrowth of hypothlamus. 13. Anatomy of neurohypophysis: It consists of a stalk which connects the pituitary gland to tuber cinereum of hypothalamus and distal,major part of neurohypophysis. 14. Mode of secretion:Contains no hormone producing cells.Instead the hormones are secreted by the neuronswhich have their cell bodies into hypothalamus.Because the posterior pituitary hormones areproduced in hypothalamus.So it is not entirely accurate to call posterior asendocrine gland,rather it acts as hormone storagestore. 15. Conti..Neurohypophysis stores and releases hormonesproduced by the neurosecretory cells of supraopticand paraventricular nuclei of hypothalamus. 16. Conti.. 17. Hormones of posterior pituitary:HormoneEffect Oxytocin Elicit milk let downIncrease uterinecontractions Antideuratic Hormone Reabsorption of waterin kidneys 18. Hormones of both lobes: 19. Intermediate lobe:The portion of adenohypophysis, in direct contactwith distal part of neurohypophysis is termed asintermediate lobe.Intermediate lobe is present between two majorparts of pituitary gland, which thing gives it its name.During embryonic development intermediate lobedevelops from epithelial tissue. 20. Anatomy of intermediate lobe:Intermediate lobe extends around neurohypophysisand the anterior lobe is separated from theintermediate lobe by the hypophyseal cleft which isalso known as cavum hypophysis. 21. Hormones of intermd. lobe:The intermediate lobe of pituitary gland producesmelanocyte stimulating hormone.Which regulates the skin colour.This hormone regulates the skin colour only in lowervertebrates but the function of this hormone is notknown in mammals and birds, although it is secreted.

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