Pituitary Gland


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Hormones of Pituitary Gland

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Pituitary Gland

  2. 2. INTRODUCTION • The pituitary gland or Hypophysis Cerebri is an ovoid structure of about 0.5 gm in adults. • It is connected to the brain through a stalk called Infundibulum.21/12/2010 Free template from www.brainybetty.com 2
  3. 3. Division in Two Lobes • The pituitary is divided into two lobes. • The anterior Pituitary. • The Posterior Pituitary.21/12/2010 Free template from www.brainybetty.com 3
  4. 4. The Anterior Pituitary • Hypothalamus (a region of brain) controls the anterior pituitary by producing: • The Releasing Hormone: Stimulates the release of pituitary hormones. • The Inhibiting Hormone: Inhibits the release of pituitary hormones.21/12/2010 Free template from www.brainybetty.com 4
  5. 5. Releasing & Inhibiting Hormones • RH and IH are produced in the cell bodies of neurosecretory neurons. • They are stored in the ends of the axons(present just above the pituitary) until needed. • When released, the hormones diffuse into capillaries draining into veins which in turn drain into capillaries of pituitary. • They then bind to the target cells causing them to release hormones.21/12/2010 Free template from www.brainybetty.com 5
  6. 6. Hormone Major target organ(s) Major Physiologic Effects Liver, adipose Promotes growth (indirectly), control of protein, Growth hormone tissue lipid and carbohydrate metabolism Thyroid-stimulating Thyroid gland Stimulates secretion of thyroid hormones hormone Adrenal gland Adrenocorticotr (cortex) Stimulates secretion of glucocorticoidsAnterior opic hormonePituitary Prolactin Mammary gland Milk production Luteinizing Ovary and testis Control of reproductive function hormone Ovary and testis Control of reproductive function Follicle-stimulating hormone Antidiuretic Kidney Conservation of body water hormonePosteriorPituitary Stimulates milk ejection and uterine Oxytocin Ovary and testis contractions 21/12/2010 Free template from www.brainybetty.com 6
  7. 7. THE GROWTH HORMONE • Protein hormone produced by anterior pituitary under the control of hypothalamus. • Production through negative feedback mechanism. • The quantity is greatest during childhood and adolescence. • The highest blood levels are during sleep and strenous exercise.21/12/2010 Free template from www.brainybetty.com 7
  8. 8. ACTION 0f GH • GH stimulates growth in the body by promoting: • Cellular Enlargement – Hypertrophy. and • Increase in the number of cells through division – Hyperplasia. • It acts primarily on bones and muscles.21/12/2010 Free template from www.brainybetty.com 8
  9. 9. ACTION 0f GH • In Bones: It stimulates cell division and protein synthesis resulting in an increase in the length and width of bones. • In Muscles: It increases uptake of amino acids and synthesis of proteins.21/12/2010 Free template from www.brainybetty.com 9
  10. 10. EFFECTS 0f GH • DAWARFISM - Under-secretion during growth phase of a child is one cause of stunted growth. - Characterized by small stature. - World’s smallest girl due to Dawarfism. (weighed 2 lbs, 8 ounces when she was born)21/12/2010 Free template from www.brainybetty.com 10
  11. 11. EFFECTS 0f GH • GIGANTISM: - Over-secretion during growth phase results in gigantism. - Giants usually have poor health.21/12/2010 Free template from www.brainybetty.com 11
  12. 12. EFFECTS 0f GH • ACROMAGELY: - Over-secretion after growth phase results in acromagely. - Feets, hands and face become overly large.21/12/2010 Free template from www.brainybetty.com 12
  13. 13. References • Human Biology , Daniel D. Chiras , Sixth Edition. • Human Biology , Sylvia S.Madar , Magraw Hill , International Eleventh Edition.21/12/2010 Free template from www.brainybetty.com 13