The Endocrine system youtube/watch?v=WVrlHH14q3o

1. Chapter 10 The Endocrine system http://www.youtube.com/watch?v=WVrlHH14q3o

2. Contributes to: • control of growth, development, reproduction, behaviour, energy metabolism, and water balance • By: • Secreting hormones • To control • Organ and tissue functions The endocrine system

3. A system of ductless secretory organs (glands) located in various parts of the body • Include • Pineal, anterior/posterior pituitary, thyroid, parathyroid, thymus, adrenal, islets of Langerhans, ovaries, testes, mammary • Main function • Secrete hormones directly into the blood or extracellular fluid Endocrine system

4. Is not a gland but a region of the brain • Part of the nervous system • Very important for function of endocrine system • Produce neurohormones that stimulate or inhibit production of other hormones in the pituitary gland Hypothalamus

5. Thyrotropin-releasing hormone (TRH) • Stimulates release of thyroid-stimulating hormone (TSH) • Gonadotropin-releasing hormone (GnRH) • Stimulates release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) • Growth hormone-releasing hormone (GHRH) • Stimulates release of growth hormone (GH) • Corticotropin-releasing hormone (CRH) • Release of adrenocorticotropic hormone (ACTH) • Somatosin • Inhibits the release of growth hormone (GH) • Dopamine • Inhibits the release of thyroid-stimulating hormone (TSH) Hormones of the hypothalamus

6. Chemical management system for the body • Chemicals produced by cells in one part of the body the regulate the processes of cells in another part of the body • Chemical messengers – act on cells from another part of the body • Local regulators – act on nearby cells • Self regulators – cells that produce chemicals to stimulate their own cellular processes Hormones: Maintaining homeostasis

8. Produced and secreted by cells, tissues and organs that compose the endocrine system (glands) directly into the blood or extracellular fluid Hormones are circulated throughout the body Only target cells will respond to specific hormones Hormones are broken down by enzymes in target cell, liver or kidneys where they are reused or excreted Hormones

9. Secreted in an inactive form –prohormones Prohormones are converted by target cells or by enzymes in the blood to an active form Angiotensinogen → angiotensin Hormones

10. Protein hormones • Consist of AA – 3 to 200 in length • Usually hydrophilic – water soluble • Diffuse well through blood • Steroid hormones • Derived from cholesterol • Not water soluble • Usually encased with protein to travel through blood • Pass easily through lipid bilayer Hormones

11. Water-Soluble • Cannot pass membrane • Bind to receptor molecules in the cell membrane • Signal is activated • Secondary messenger is activated • Change is caused inside cell • Acts in the cytosol or the nucleus • Glucagon • Breakdown of glycogen into glucose Hormone mechanisms

13. Lipid-Soluble • Can pass membrane (lipid) • Bind to receptors inside a cell (cytosol or nucleus) • Turn on or off an action of a specific gene • Changes amount of protein that is synthesized by cell • Aldosterone • Increase sodium absorption → increases water retention → increase blood pressure Hormone mechanisms

15. Only the cells that contain surface or internal receptors for the hormones respond to the hormones Once bound to their receptors, hormones produce a response by turning cellular processes on or off. They do this by altering the proteins that are functioning in or produced by the cell Hormones are effective in very small concentrations because of the amplification that occurs in both the surface and internal receptor mechanisms The response to a hormone differs among target organs and among species Major features of hormone mechanisms

16. Secretion of hormones are regulated by negative feedback mechanisms Hormones inhibit other hormones Multiple hormones can be secreted at a time Hormones: negative feedback mechanisms

18. The Master Gland • Produces hormones that control most of the other endocrine glands The pituitary gland

19. Made up of anterior lobe and posterior lobe • Links endocrine system to nervous system via portal vein (hypothalamus) • Influenced by hypothalamus • Releasing hormones/inhibiting hormones The pituitary gland

20. 2. portal vein • 4. anterior pituitary gland • 5. hypophyseal vein • 6. posterior pituitary gland • 8. pituitary stalk • 9. capillary network • 10. neurons • 11. neurosecretory cells • 12. hypothalamus

21. Secretes 6 major hormones into the bloodstream which influence hormone secretion in other glands • Prolactin, growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone • Other hormones produced • Melanocyte-stimulating hormone, endorphins Anterior pituitary gland

22. prolactin

23. Cell division, protein synthesis, bone growth • IGF – insulin growth factor that stimulates these functions • Also • Conversion of glycogen to glucose, fats to fatty acids – regulates levels in blood • Stimulates cells to take up FA, AA and limits muscle cells to take up glucose Growth hormone

24. Underproduction – dwarfism Overproduction – gigantism Growth hormone

25. Thyroid-stimulating hormone

26. Adrenocorticotropic hormone

27. Follicle-stimulating hormone/luteinizing hormone

28. Causes darkening in humans causing the release of melanin in the skin and hair Protects from UV rays Melanocyte-stimulating hormone

29. Natural pain killers Endorphins

30. Stores and releases 2 major hormones into the bloodstream • Antidiuretichormone (vasopressin), oxytocin • These hormones are produced by the hypothalamus and stored here Posterior pituitary gland

31. Causes distal convoluted tubule to become permeable to water Helps maintain water balance Antidiuretichormone (vasopressin)

32. oxytocin

33. Located in the front of the throat and shaped like a bow tie • Secretes • thyroxine (T₄), triiodothyronine, calcitonin Thyroid gland

34. Contains 4 iodine atoms When iodine levels are low thyroid will continue to grow resulting in a goiter Thyroxine (t₄)

35. Protein hormone that lowers levels of Ca²⁺in blood calcitonin

36. 4 spherical glands (size of a pea) located on each side of the posterior surface of the thyroid gland • Secretes • Parathyroid hormone Parathyroid gland

37. Stimulates enzymes in kidneys to convert vitamin D into calcitrol increasing absorption of Ca²⁺ and phosphates from food • Underproduction • Muscle cramps • Osteoporosis • Overproduction • Kidney stones Parathyroid hormone

38. Consist of two regions • Adrenal medulla – contains highly modified neuro-secretory neurons • Adrenal cortex – contains non-neural endocrine cells Adrenal glands

39. Secretes • Epinephrine, norepinephrine • These chemicals can act as hormones or neurotransmitters (transmit nerve signals) • Part of the “fight or flight” response Adrenal medulla

40. Released when body encounters stresses • Epinephrine • Increase heart rate • glycogen and fat breakdown • Skeletal muscles, lungs blood vessels dilate increasing blood flow • Blood vessels everywhere else constrict • Blood pressure raises • Reduces water loss • Digestive system slows • Used to counter anaphylaxis Epinephrine/norepinephrine

41. Secretes • Aldosterone, cortisol Adrenal cortex

42. Located near the centre of the brain • Regulates several biological rhythms • Photoreceptors in the eyes influence pineal gland – light inhibits melatonin secretion • Helps to synchronize biological clock • Secretes • melatonin Pineal gland

43. Occurs automatically in our body • Pancreas – contain both exocrine/endocrine glands • Exocrine • secretes digestive enzymes into the small intestine • Endocrine • Islets of Langerhans - Secretes insulin (beta cells) and glucagon (alpha cells) Regulating blood sugar

44. Regulate the ability of most tissues in the body to metabolize fuel substances (glucose, fats, proteins) Insulin/Glucagon

45. Secreted by beta cells • Lower blood glucose levels by • Acts on skeletal muscles, liver cells, adipose tissue (fat) to uptake glucose • In the Liver • Lowers fatty acid levels • promotes fatty acid uptake and storage in adipose tissue • Inhibits breakdown of fats into fatty acids • Lowers amino acid levels • Promotes protein synthesis • Inhibits breakdown of proteins insulin

46. Secreted by alpha cells • Increase blood glucose levels by • Stimulating breakdown of glycogen into glucose • Stimulates breakdown of fats into fatty acids • Stimulates breakdown of proteins into amino acids • Stimulate cells to use amino acids and non-carbohydrates to synthesize glucose glucagon

47. Cortisol – Helps raise blood glucose levels using three mechanisms • Stimulate synthesis of glucosefrom fats and proteins • Reduce glucose uptake by the body cells except in the central nervous system • Promote breakdown of fats and proteins into fatty acids and amino acids as alternative fuels glucocorticoids

48. Glucose levels throughout the day

49. Hyperglycemia (above 200mg/dL of blood) • Blood glucose levels are too high • (norm 115-200mg/dL) • Symptoms • Frequent urination, sugar in the urine, vision problems, fatigue, weight loss • Hypoglycemia (below 70mg/dL of blood) • Blood glucose levels are too low • (norm 70-115mg/dL) • Symptoms • Nervousness, cold sweats, hunger, headaches, weakness Unstable levels of glucose

50. High glucose levels in the blood caused by problems with insulin production • Symptoms • Frequent urination, increased thirst, increased appetite • Classified into three different types • Type 1 • Type 2 • Gestational diabetes