Endocrine System

1. Endocrine System Chapters 21, 22, 23, 24, 26

2. Endocrine System • Endocrine system regulates essential activities of the body • Metabolism of nutrients • Reproduction • Growth and development • Adapting to change in internal and external environments

3. Major Elements of Endocrine System • Hypothalamus • Pituitary gland • Thyroid gland • Parathyroid glands • Pancreas • Adrenal glands • Ovaries • Testes

5. Local Tissue Hormones Endocrine like cells in the • Gastrointestinal mucosa – hormones that aid in digestion • Kidneys – erythropoietin – hormone that stimulates bone marrow to produce RBC’s • White blood cells – cytokines – inflammation • Body tissues – prostaglandins and leukotrienes

6. Tumors • Specific tumors produce hormones • Lungs - ACTH • Kidney – parathyroid hormones Elevation of these hormones would aid in diagnosing the tumors

7. Endocrine System and Nervous System • Closely connected • Work together to regulate body function • Main connecting link is the hypothalamus – responds to nervous system stimulation by producing hormones

8. What is the Endocrine System? • Endocrine system is in charge of the body processes that happen slowly, such as cell growth. • The nervous system has to do with the faster processes, like breathing and body movement.

9. Hormones • The bodies chemical messengers • Different hormones circulate throughout the blood stream, but only affects the cells they are genetically programmed to receive and respond to the message.

10. Hormone Pharmacokinetics • Water soluble hormones, protein-derived hormones have a short duration of action and are inactivated by enzymes in liver and kidneys • Lipid soluble hormones and thyroid hormones have a longer duration because they are bound to plasma protein – they are broken down in the liver and excreted in bile or urine

11. Water Soluble Hormones • Do not enter the target cells – form weak bonds with receptor sites on the cell membrane • Sometimes called the “second messenger” • Examples: glucagon, adrenalin and parathyroid hormones

12. Glucagon • Has a major role in maintaining normal concentrations of glucose in the blood. • Glucagon increased blood glucose levels

13. Adrenalin • Adrenalin or epinephrine is a hormone that acts as a neurotransmitter. • Most well known hormone secreted by the adrenal glands.

14. Parathyroid Hormone • Four parathyroid glands about he size of a grain of rice. • Thyroid and parathyroid glands do not interact with each other. • Parathyroid gland regulated calcium in the body. • Electrical energy for nervous system • Electrical energy for muscular system • Strength of skeletal system through storage of calcium

15. Parathyroid Gland

16. Lipid Hormones • Two know types of lipid soluble hormones are steroids and thyroid hormones. Both travel over long courses of time via the blood stream and directly effect DNA functions.

17. Steroid Hormones • Androgens: male sex organs, sperm production, muscle mass and human aggression • Estrogen and Progesterone: female sex organs and characteristics • Mineralocorticoids: water balance / sodium / potassium • Glucocorticoids: carbohydrate metabolism / immune function

19. Cellular Response • Up-regulation – receptors may be increased if there are low levels of hormone • Down-regulation – hormones may be decreased when there are excessive amounts

20. Hormone Disorders • Abnormal secretion and function of hormones can impair physical and mental health • Hypersecretion (too much) • Hyposecretion (too little)

21. What Can Influence Hormone Levels? • Stress • Infection • Fluid balance • Minerals in blood • Structural changes in glands

22. Glandular Hypofunction • Congenital defect - infant • Damaged or destroyed – inflammation - tumor • Atrophy of gland due to aging – geriatric population • Receptor defects in the gland • Intracellular processes malfunction – cellular level

23. Hormonal Drugs • Potent drugs that produce widespread therapeutic and adverse side effects • Given when there is hypofunction of a gland

24. Two Common Hormonal Drugs • Pancreas dysfunction – insulin needed to regular blood sugar levels • Thyroid dysfunction • hypothyroid conditions – need replacement of hormone • hyperthyroid may need to give medication that inhibits excess thyroid produced

25. In a nut-shell • With hormones the body needs a consistent amount to properly function – too much or too little can be a problem

26. Hypothalamic and Pituitary Chapter 22

27. Pituitary Gland • The pituitary gland is sometimes called the "master" gland of the endocrine system, because it controls the functions of the other endocrine glands. The pituitary gland is no larger than a pea, and is located at the base of the brain. The gland is attached to the hypothalamus (a part of the brain that affects the pituitary gland) by nerve fibers.

29. Pituitary / Hypothalamic • The pituitary gland is the Master gland of the body. The anterior and posterior pituitary secretes a battery of hormones that influence all cells and affect all physiological processes.

32. Anterior Pituitary Gland • Anterior pituitary gland – • Growth hormone • Adrenal cortex – ACTH – glucocorticoids • TSH – thyroid stimulating hormone • FSH – follicle stimulating hormone – ovary – estrogen and progesterone • LH - luteinizing hormone – stimulates ovulation • Prolactin – breast tissue – milk production • Testosterone – testes

33. Medical Conditions • Growth Hormone Therapy in pediatrics • To stimulate secondary sexual characteristic in adolescents with delayed puberty • Infertility • Thyroid conditions

34. Growth Hormone Deficiency • In a child what do you think you might see? • Height versus weight • Growth curve • What influences growth? • How do you tell the drug is working?

35. Posterior Pituitary Gland • ADH – antidiuretic hormone – kidney – regulates water balance • Oxytocin – uterus and breast – labor and breast feeding

36. Posterior Pituitary Dysfunction • Desmopressin (DDAVP) or vasopressin – synthetic ADH (antidiuretic hormone) • Clinical Diagnosis: diabetes insipidus – characterized by high output of dilute urine – can be idiopathic (do not know the cause) – can occur after head trauma, with tumor of hypothalamus or posterior pituitary • Importance of intake and output and specific gravity of urine (1.010 is normal)

37. Intake and Output • Why important? • How besides urine output can a person lose fluid? • Basic measures of intake and output – ml’s or cc’s

38. Diabetes Insipidus

39. Posterior Pituitary Hormone • Oxytocin – promotes uterine contractibility • Clinical uses: After delivery of infant and placenta in obstetrics. • In small dosages to stimulate or induce labor in a pregnant woman • When you will be doing your obstetrical rotation you will see oxytocin (Pitocin) given IV after delivery to help the uterus to contract.

40. Ethical Consideration • Abuse of Human Growth Hormone in athletes to improve performance – older people in search of the “fountain of youth” • Ovary stimulating drugs use to produce numerous ovaries to be artificially inseminated and implanted – may lead to selective abortion of excess embryos after implantation

41. Corticosteroids Chapter 23

42. Corticosteroids • Controlled by the hypothalamus • Rate of secretion is kept within a very narrow range • “negative feedback mechanism” when too much is released the mechanism for release shuts down Very important concept when we give steroid to a patient – the higher plasma levels effectively shuts down the bodies production of the drug naturally – this is a drug that cannot be abruptly stopped – needs to be tapered

43. Corticosteroids • Produced by the adrenal cortex • Involved in stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte levels and behavior.

44. Two Types • Glucocorticoids: anti-inflammatory • Mineralocorticoids: aldosterone – controls electrolyte and water levels

45. Uses of Corticosteroids • Use to treat a number of different disorders especially inflammatory or immunologic disorders • Arthritis • Dermatitis • Allergic reactions • Asthma • Hepatitis • Lupus erythematosus • Inflammatory bowel disease: ulcerative colitis and Crohn’s disease • Uveitis – inflammation of eye

46. Use in Orthopedics • Cortisone can be injected directly into a joint to reduce inflammation • Medrol dose pack is often prescribed for chronic back pain

47. When not to use Corticosteroids • Fungal infections – thrush – vaginal yeast infections • Clients who are high risk for infection • Diabetes • Peptic ulcer • Hypertension • CHF • Renal Failure

48. How Administered • Topical – skin rashes - hydrocortisone • Eye drops / ear drops: cortisone ear drops or Prednisolone Ophthalmic suspension • Nasal – Nasonex • Tablet or liquid form – prednisone, Decadron • IV – methyl prednisone or Solu-medrol • Inhaled - asthmatic or COPD

49. Goals of Therapy • To reduce symptoms to a tolerable level • Total suppression of symptoms may require excessive dosages • Avoid serious side effects

50. Clinical Pearl • Whenever possible the physician / nurse practitioner will prescribe a topical, nasal spray, eye drops or inhaled dosage before going to an oral route or intravenous route. • Oral and intravenous routes are usually higher dosages and more likely to have side effects.