Endocrine System Defifnitions and other glands

All the informations in this Power Point Presentation is about the human Endocrine system.

1. Endocrine System

2. Definition Second control system. Release chemical called hormones. Greek (to arouse) Altering cellular activity Either increasing or decreasing the rate of a normal, or usual metabolic process

3. Hormones Classification Amino-acid based molecules Proteins, peptides, and amines Steroids (cholesterol) Actions Affects target cells or target organs

4. Hormones can: Change plasma membrane permeability or membrane potential (electrical state) by opening or closing ion channels Activate or inactive enzymes Stimulate or inhibit cell division Promote or inhibit secretion of a product Turn on or turn off transcription of certain genes (such as those encoding proteins or regulatory molecules)

5. Mechanism of Hormone Action

6. Endocrine Gland Stimuli

7. Location of Major Endocrine Gland

8. Pituitary Gland & Hypothalamus PG (master EG) Divided into APG & PPG Hypothalamus The APG is controlled by hypothalamus hormones (releasing and inhibitory) Also produces Oxytocin and ADH

9. PPG Not EG instead storage of hormones:

10. PPG Oxytocin Released significantly during childbirth and nursing. Stimulates powerful uterine contraction. (sex, labor, breastfeeding) Milk ejections (let-down reflex) for nursing mothers. Stop post-partum bleeding ADH (Anti Diuretic Hormone) Prevents urine production Sometime referred as vasopressin (vasoconstrictor causing increase BP)

11. APG

12. APG Non ENDO targets GH prolactin Tropic (Turn on) FSH LH Tyrotropic Adrenocorticotropic (ACTH)

13. Growth Hormone General metabolic hormone Effects Growth of SM and LB (final size of the body Target cells to grow in size and divide. Causes fats breakdown (energy) while sparing glucose.

14. Prolactin Pro (for) lactin (milk) Target is human breast (lactation) Effects unknown to males.

15. Gonadotropic FSH Women Follicle development in ovaries (maturation) Produce estrogen and eggs readied for ovulation Men Stimulates sperm development by the testes LH Women Triggers egg ovulation (ovary) Causes ruptured follicles to produce Pro & Estro Men Stimulates testosterone production by the testes.

16. TH (Thyrotropic Hormone) TH or TSH (Thyroid Stimulating Hormone) Influences the growth and activity of TG ACTH Regulates the endocrine activity of the cortex of the AG (kidneys)

17. Pineal Gland Many chemical substance secreted but: Melatonin (substantial amount) Peak Level at night Lowest Level at daytime “SLEEP Trigger”

18. Thyroid Gland Located at the base of the throat. Makes 2 hormones (major metabolic hormones) T₄ (thyroxine) & T₃ (triiodotyronine) T₄ secreted by thyroid follicles T₃ conversion from T₄ at the target tissue TH controls the rate at glucose oxidation. TH important for normal tissue G&D (reproductive & nervous systems)

19. Thyroid Gland Calcitonin (produced at parafollicular cells) Decreases Ca ion in the BS (calcium deposited to bones) Antagonistic to PTH Production ceases entirely in adults Bone decalcification (in part)

20. PTG (Parathyroid Gland) Found at the posterior surface of the TG Normally 2 PTG per lobe of TG (4) Reported as many as eight Secretes PTH When blood Ca drops PTG releases PTH then stimulates bones destruction cells (osteoclast) Then break down of bone matrix and releasing CA to bloodstream. PTH also targets the kidney & intestine (absorb more Ca)

21. Therefore Calcitonin (hypocalcemic) PTH (hypercalcemic)

22. Thymus Upper thorax posterior to the sternum. Large (infant &childhood) Decreases size (adult) Produces THYMOSIN Essential for the normal development of special group of WBC T lymphocytes Immune response

23. Adrenal Gland

24. Hormones of AG Adrenal Cortex Corticosteroids Mineralocorticosteroid (aldosterone) Glucocorticoids Cortisone Cortisol Sex Hormones M (androgens) F (estrogens) Adrenal Medulla Stimulated by SD of ANS Catecholamines Epinephrine (adrenaline) Norepinephrine (noradrenaline)

25. AG (AC) Mineralocorticosteroid (aldosterone) Important in regulating blood electrolytes (Na & K) Hormone targets the kidney tubules More Na reabsorb, more K out in the urine When Na reabsorb more H₂o reabsorb What stimulates the release of aldosterone? Humoral (decrease blood Na or increase blood K)

26. AG (AC) Lesser degree (Renin) BP drops, kidney release renin (enzyme) Renin released, conversion of Angiotension I to Angiotensin II then stimulates the release of aldosterone Heart release ANP (atrial natriuretic peptide) Prevents aldosterone release then decreases blood volume and BP

27. Glucocorticoids Cortisone & Cortisol Promotes normal cell development Helps body to resist long term stressors by: Increasing blood glucose level When blood glucocorticoids are high, fats even proteins are converted to glucose (hyperglycemic hormones) Decreases edema and inhibits prostaglandins during inflammatory response What triggers the release from AC? Rising blood ACTH

28. AG (Sex Hormones) Male (androgens) Female (estrogens)

29. Adrenal Medulla Stimulated by SD Catecholamines Epinephrine (adrenaline) Norepinephrine (noradrenaline) Fight or Flight (alarm stage) Increase HR, Increase BP, Increase Blood Glucose, dilate airway Increase O₂ and Energy to deal short term stress (Brain, Heart, Muscle) But for long term stressors (resistance stage) Glucocorticoids

30. Pancreas Pancreatic Islets (Islets of Langerhans) Beta Cells (Insulin) Apha Cells (glucagon) Liver is the TO Glycogen to glucose

31. Hormones of the Ovaries Produce two steroid hormones Estrogens Development of sex characteristics G&D of female RO Appearance of secondary sex characteristics Hair in pubic and axillary region Acting with progesterone Promote breast development and for menstrual cycle Progesterone Acting with estrogens Menstrual cycle Pregnancy Quiets the muscles of the uterus (prevents abortion) Prepare breast tissue for lactation APG (gonadotropic) triggers the release of these hormones (cyclic)

32. Hormones of the Testes Androgens Testosterone is the most important Puberty Promotes growth and maturation of men’s RSO for reproduction. Makes the secondary sex characteristics Growth of facial hair Development of heavy bones of muscles Lowering of the voice Adults Necessary for continuous sperm production Stimulated by the LH