1. Anatomy and Physiology of The Endocrinal System Dr. Miada Mahmoud Rady EMS / 474 Endocrinal Emergencies lecture 1

2. Topics 1 Introduction. Overview of the whole endocrine system. 2 Mechanism of hormone regulation. Hormonal control of the endocrine system. 3 Function of hormones. Individual body glands.

3. Introduction Endocrine system is the body second great controlling system. The endocrine system influences almost every cell, organ, and function of the body. That is why patients with an endocrine disorder often have a broad range of signs and symptoms.

4. Overview of the whole endocrine system  System of ductless glands that produces and secrete hormones.  Ductless i.e. without a duct i.e. it releases hormones directly into the blood stream.  Function : it acts in conjugation with the nervous system to control several body function by secretion of hormones

5. Main Glands Of The Endocrine System: 1.Pituitary gland. 2.Pineal gland. 3.Thyroid gland. 4.Parathyroid gland. 5.Suprarenal gland. 6.Pancreas. 7.Gonads.

6. Hormones 1.Messenger molecules. 2.Circulate in the blood to act on distant target cells. 3.Target cells respond to the hormones for which they have receptors. 4.The effects are dependent on the programmed response of the target cells, it could be either agonist or antagonist effect. 5.Some hormones acts only on single organ cells while others act on multiple.

7. Mechanisms of Hormone Regulation 1.Humoral: in response to changing levels of ions or nutrients in the blood. 2.Neural: stimulation by nerves. 3.Hormonal: stimulation received from other hormones.  Hormones operate within positive or negative feedback systems to maintain an optimal operating environment in the body.

9. Hormonal control of endocrine glands secretion  Endocrine regulation maintains hormone secretion through Negative Feedback.  Drop in the level of a hormone triggers a chain reaction of responses to increase the level hormones in the blood.  Disease occurs System Stops Providing Negative Feedback to regulate function i.e. Positive Feedback Is Given.

10. Function of hormones 1.Increase or decrease rate of cellular metabolism 2.Transfer information between cells to coordinate body functions such as Growth and Development, Metabolism, Hemostasis, Reproduction, Response to Stress And Sexual Development And Function

11. MMR Individual Components Of The Endocrine System

12. Hypothalamus Located in the brain. Produces two categories of hormones : 1.Several releasing and inhibiting factors that stimulate such as (TRH, CRH, GHRH,PRF and GnRH) or inhibit (GH inhibiting hormone, PIF) anterior pituitary’s secretion of hormones. 2.Hormones that are stored in and released from posterior pituitary( Oxytocin and ADH).

13. HormoneNamefunction GHRHGrowth hormone releasing hormoneStimulate GH release GnRHGonadotropin releasing hormoneStimulate LH & FSH release TRHthyroid releasing hormoneStimulate TSH release CRHcorticotropin releasing hormoneStimulate ACTH release PRFProlactin releasing factorStimulate prolactin release GHIHgrowth hormone inhibiting hormoneInhibit GH release PIFProlactin inhibiting factorInhibit prolactin release ADHAntidiuretic hormoneStimulate water reabsorption Oxytocin Uterine contraction and milk ejection. Hormones released by hypothalamus

14. Pituitary gland Located at the Base Of The Brain. Connected to the hypothalamus by Hypothalamo-pituitary Stalk. Also known as Master Gland because its main function is to control secretions of the other glands. Secretion of pituitary gland is controlled by releasing and release inhibiting factors of the hypothalamus.

15. So what do the anterior pituitary hormones do? A.TSH : stimulates the thyroid gland to produce thyroid hormone B.ACTH : stimulates the adrenal cortex to produce corticosteroids. C.FSH : stimulates follicle growth, estrogen production and also sperm production. D.LH : play major rule ovulation and the growth of the corpus luteum.

16. So what do the anterior pituitary hormones do? A.GH : stimulates growth of the bones by closure of epiphyseal plates. B.PRL : stimulates mammary glands in breast to make milk. C.MSH : stimulates melanocytes and may increase mental alertness.

17. What about the posterior pituitary hormones? 1.ADH (antidiuretic hormone i.e. vasopressin) : stimulates the kidneys to reclaim more water from the urine, raises blood pressure. 2.Oxytocin : prompts contraction of smooth muscle in reproductive tracts, initiation of labor and ejection of milk from breasts Remember posterior pituitary only secretes hormones

18. So pituitary hormones are: Large anterior lobeSmall posterior lobe Releases hormonesStores hormones Growth hormone (GH) Oxytocin Thyroid Stimulating hormone (TSH) Anti Diuretic hormone (ADH) Adenocorticotropic hormone (ACTH) Luteinizing hormone Follicule stimulating hormone Melanocyte stimulating hormone Prolactin

19. Thyroid gland Located in the front of the neck. Divided into two lateral lobes connected by an isthmus. Thyroid gland secretes 3 hormones : A.Thyroid hormones : T3 and T4, both secreted from Follicular Cells. B.Calcitonin : secreted from parafollicular cells.

20. Effects of Thyroid Hormone A.Increases the Basal Metabolic Rate : it is rate at which the body uses oxygen to transform nutrients into energy. B.Affects many processes and cells throughout the body as : 1.Protein synthesis 2.Bone growth 3.Neuronal maturation 4.Cell differentiation

22. The Parathyroid Gland Located on the posterior surface of the thyroid gland, sometimes embedded. Secretes parathyroid hormone (PTH): PTH increases ca level by : 1.Increase of Ca 2+ release from bone by osteoclasts. 2.Increases intestinal absorption. 3.Increase renal reabsorption of calcium.

23. The Supra Renal Glands  Paired, triangular shaped gland.  Located at the upper pole of the kidney.  Divided into two parts : 1.Cortex : the outer part, secrets 3 types of hormones ( Glucocorticoids, Mineralocorticoids And Androgens). 2.Medulla : inner part, secretes Catecholamines.

24. Anatomy of the thyroid gland

25. Corticosteroids 1.Help the body deals with stressful condition whether physical e.g. trauma or surgery, psychological e.g. depression and physiological e.g. fasting. A.Supporting and regulating several metabolic, cardiovascular, immunologic and haemostatic function. B.Hyperglycemia i.e. increasing blood glucose level to support brain.  That’s Why Corticosteroids Are Essential For Life.

26. 2.Catabolic effects e.g. increase protein break down. 3.In large doses it suppresses the immune system. And that is why steroids are used in treatment of autoimmune disorders and to suppress immune system in transplant patient to prevent rejection. And that is why steroids are used in treatment of autoimmune disorders and to suppress immune system in transplant patient to prevent rejection.

27. Mineralocorticoids  Increase Sodium and Water Reabsorption from the kidney leading to increase in blood volume and increase in the blood pressure.  Main mineralocorticoid is Aldestorone, it is secreted in response to Hypotension or Hypovolemia.

28. Effect of adrenal medulla hormones

31. The Pancreas  Flattened intra-abdominal organs.  Consists of both endocrine and exocrine cells (mixed gland).  Endocrine cells is called islets of Langerhans.  There are 3 types of islet cells ; alpha, beta and delta, each secrete different hormone.

32. Hormones of the pancreas CELLSHARMONEEFFECT Alpha (  ) cells GlucagonGlucose synthesis & glycogen breakdown in liver  Blood glucose concentration Beta (  ) cells InsulinStimulation of lipids & glycogen storage & formation  Blood glucose concentration Delta (  ) cells SomatostatinInhibits secretion of insulin & glucagon

33. Home work

34. In the previous two pictures, please mention the labeled glands and describe the function of at least two of them. This home work should be sent by e-mail in ward format before next lecture.

35. MMR Thank you