Chapter 9 Endocrine system – cells, tissues, or organs that secrete hormones

1. Chapter 9 Endocrine system – cells, tissues, or organs that secrete hormones Hormone – substance that stimulates changes in cells and regulate metabolic processes Hormones are target specific, meaning the target cells have specific receptors that bind to specific hormones. Functions of hormones: A. control chemical reactions B. regulate water and electrolytes

4. C. regulate growth and reproduction D. aid in transport of substances into/out of cell E. defend against stressors F. regulate energy and metabolism Types of hormones: A. Local – not considered to be ‘true’ hormones because they are released and act locally, but they have functions similar to hormones: Paracrine – affect neighboring cells Autocrine – affect only secretory cells

5. Prostaglandins are lipid-based local hormones. Prostaglandins are released due to local irritation or by actions of other hormones. Effects: A. relax smooth muscles in blood vessels and lungs B. cause smooth muscle contractions in uterus and small intestines C. inhibit stomach excretion of HCl D. affect movement of sodium water in kidneys E. induce inflammation, fever, pain F. enhance blood clotting

7. Steroid derived hormones – contain rings of carbon and hydrogen atoms, are insoluble in water and soluble in lipids, can easily diffuse across the membrane, and are transported through the membrane. • Actions: • 1. hormone diffuses through cell membrane • hormone forms a complex protein, which activates the • 3. DNA to start protein synthesis • 4. Transcription and translation forms proteins, which carries out the effects of the hormone

8. Amines, peptides, and protein derived hormones. • Actions: • 1. hormone binds with a receptor on cell membrane • 2. biochemical changes occur within the cell (known as the first messenger) • 3. chemicals respond to the first messenger (known as second messenger) stimulate the formation of cAMP (cyclic adenosine monophosphate) • 4. cAMP activates proteins in the cell that carry out hormone’s effects

10. Hormones are continuously broken down in the liver and excreted in the urine. Hormones are controlled by three different negative feedback mechanisms: • Hypothalamus control –monitors blood hormone concentrations and stimulates release of hormones from other organs. • Nervous system – directly stimulates release of hormone via SNS • 3. Endocrine glands – directly respond to changes in blood composition

14. Endocrine Glands are glands that release hormones 1. Pituitary – part of hypothalamus – made of two parts: a. anterior lobe b. posterior lobe Anterior lobe secretes hormones controlled by releasing hormones of the hypothalamus. Hormones of anterior lobe A. Somatotropin (growth hormone) effects: 1. ↑ in cell size, ↑ cell division 2. ↑ speed of cell’s use of fats and carbohydrates 3. ↑ movement of amino acids into cells Hypersecretion leads to gigantism in children, acomegaly in adults of hands, feet, and face Hyposecretionleads to dwarfism in children (normal body proportions and mental abilities)

15. JyotiAmge - Nagpur, India, Friday, Dec. 16, 2011. Amge, 18, was declared shortest woman in the world measuring 62.8 centimeters (24.7 inches) by the Guinness World Records. (AP Photo/Manish Swarup)

16. Tallest man 8’ 11’’ Tallest woman – 7’ 8 ½”

17. acromegaly

18. B. Prolactin – stimulates production of milk after birth • Hypersecretion leads to galactorrhea, cessation of menstrual cycle, impotence in males • Hyposecretion leads poor milk production • C. Thyroid stimulating hormone (TSH) – controls secretions of the thyroid gland • D. Andrenocorticotropic hormone (ACTH) – regulates hormones released from adrenal gland • Follicular stimulating hormone (FSH) regulates the production of sex hormones • Females – causes follicles to mature and stimulate estrogen production • Males - ↑ testosterone production

20. F. Luteinizing hormone (LH) regulates the production of sex hormones • Females – triggers ovulation and production of progesterone • Males – ↑ testosterone production • Posterior lobe hormones – release is controlled by nerve impulses from the brain. Types of posterior hormones: • Antidiuretic hormone (ADH) – regulated by osmoreceptors (detect changes in body fluid pressure) located in brain • When there is an increase in dissolved solutes and a decrease in water (ex: dehydration), the brain stimulates the posterior pituitary to release ADH. ADH is also released in response to pain, low blood pressure, and sever hemorrhage.

21. ADH – released into bloodstream, travels to kidneys, causes kidney to ↓ urine output Hyposecretion leads to diabetes insipidus and causes increased urine output and thirst. B. Oxytocin is released in response to stretching of the uterus and nursing. Effects: 1. ↑ uterine contractions during childbirth 2. ↑ release of milk after childbirth

22. 2. Thyroid gland is located inferior to the larynx. There are two lobes, one on either side of the trachea, and are connected by an isthmus. There are two types of secretory cells: 1. follicular 2. Parafollicular Hormones of follicular cells: A. thyroxine – T4 – most abundant – contains 4 iodine atoms B. triiodothyronine – T3 – formed from conversion of T4 TSH controls the release of thyroxin and triiodothyronine.

23. Effects (same for both hormones): 1. regulate metabolism 2. determines BMR – basal metabolic rate 3. stimulate breakdown and metabolism of lipids 4. ↑ rate of protein synthesis Hypersecretion – Graves disease – due to autoimmunity against the thyroid gland. The symptoms of Graves disease are: increased metabolic rate, excessive perspiration, irregular heart beat and nervousness, weight loss, and exophtalamos (protruding eyeballs).

24. GOITER Exophtalamos – Graves disease

25. Hypothyroidism occurs when there is not enough thyroxine in the blood stream. This can be due to: A. lack of iodine in diet (goiter –inflammation of thyroid) B. defective thyroid gland C. problems with release of TSH Cretinism – in children – will result in cretin dwarf. The children will have short and disproportioned bodies and mental deficiencies. Myxedema – in adults – decreases metabolic rate, produces dry and thick skin, puffy eyes, edema (retention of body fluids), feeling of being chilled, and weight gain.

26. Creatinism

27. Hormone of parafollicular cells - calcitonin Calcitonin is released in response to an increase in blood calcium level (hypercalcemia). Calcitonin – made by parafollicular, released with ↑ calcium (hypercalcium) ↑ kidney excretion of Ca+2 and PO4-3 ions, inhibits osteoclasts from reabsorbing bone, ↓ absorption of calcium from intestinal tract Parathyroid glands are four glands on the posterior surface of the thyroid gland. It secretes parathyroid hormone (PTH) in response to a decrease in blood calcium level (hypocalcemia). PTH causes kidneys to conserve water, enhance absorption of calcium from intestine, and activate osteoclasts to breakdown bone and release calcium

29. Adrenal glands are located atop of each kidney. They are made of two portions: Adrenal cortex, adrenal medulla The secretion of the hormones of the adrenal gland is regulated by the sympathetic nervous system. Adrenal medulla releases epinephrine Effects of epinephrine: A. ↑ breathing rate B. ↑ heart rate, blood pressure, force of heart contraction C. ↑ release of glucose into blood D. ↓ digestive motility

31. Adrenal cortex releases aldosterone, cortisol, and androgens Aldosterone helps regulate concentration of mineral electrolytes (Na+, K+, Cl-, etc.), which affects blood pressure and volume. Aldosterone is regulated by a decrease in blood pressure and the concentration of sodium and potassium ions in the blood. Aldosterone causes the kidneys to conserve sodium and potassium ions. This causes an increase in water re-absorption, which increases the volume of blood. An increase in blood volume will increase blood pressure.

32. Cortisol affects glucose metabolism. It is released between meals or hypsecreted during stressful situations. Effects: • 1. inbibit protein synthesis • 2. promote release of fatty acids, ↑ usage of fat for cell energy • stimulates liver cells to synthesize glucose from amino acids and fats, ↑ blood glucose level • Excess cortisol may lead to: high blood pressure, atherosclerosis, depressed immune system, ulcers • Hypersecretion causes Cushings disease. - tissues retain water (edema), hyperglycemia, loss of muscle and bone proteins, hypertension

33. Hyposecretion causes Addison’s disease – severe dehydration, hypotension, weight loss, decrease glucose level Androgens are sex hormones that stimulate the development of reproductive organs. The production declines after puberty. After menopause, women convert these hormones into estrogen to help maintain reactions associated with estrogen. 5. Pancreas is posterior to the stomach and has ducts that lead into the small intestines. Islets of Langerhans produce glucagons (from alpha cells) and insulin (from beta cells).

35. Pancreatic hormones: • Insulin is released when blood glucose level is elevated. Insulin decreases blood glucose by: • 1. promoting cell uptake of glucose • 2. inhibit conversion of protein and fats into glucose • 3. stimulate liver to store glucose as glycogen • 4. promote transfer of amino acids into cells • increase protein synthesis

36. Glucagon is released when the blood glucose level drops. Glucose increases blood glucose level by: • 1. stimulate liver to convert glycogen into glucose • 2. promote proteins and lipids to form glucose • Diabetes mellitus is due to a deficiency of insulin; the blood glucose level increases (hyperglycemia). Effects: • 1. ↑ glycogen formation • 2. excrete excess glucose into urine (glycosuria) • 3. abnormal water excretion by kidney • 4. dehydration and extreme thirst (polydispia) • 5. ↓ protein and fat synthesis • 6. proteins and fats used for energy

37. 7. ketones released when fats used for energy – disrupts blood pH – may lead to coma 8. muscles atrophy as proteins used for energy 9. excess hunger and food consumption (polyphagia) 10. long term: retinal disease, coronary artery disease, nerve damage

38. Types of diabetes: • 1. Type I – autoimmune disease against the beta cells of the islets of Langerhans – usually affects children. Since insulin is not produced, the affected individual must monitor blood glucose levels on a daily basis and take insulin injections. • 2. Type II – most common and will develop milder symptoms. Insulin is produced but cells are sensitized to insulin. Fat cells produce a hormone that blocks the uptake of glucose by cells. Exercise, weight loss, and a decrease in foods with high sugar content will help control Type II diabetes. • Hypoglycemia occurs when the blood sugar level falls to dangerously low levels. The effects are: • a. disorientation – lack of glucose to brain • b. convulsions • c. unconsciousness • d. death - extreme

39. 6. Pineal gland is located in the epithalamus. It releases melatonin, which helps to regulate the sleep-wake cycle.

40. 7. Thymus gland is located between the lungs (superiorly) and secretes thymosin and thymopoietin. These two hormones cause T-cells to mature. In adults, the thymus gland is replaced by fat. • 8. Reproductive glands: • a. Females – ovaries produce estrogen and progesterone • b. Males – testes release testosterone

41. Miscellaneous hormones • a. ANP – atrialnatriuretic peptide – stimulates kidneys to increase urine production and decrease blood pressure • b. gastrin – stimulate HClrelease by stomach • c. erythropoietin – stimulate RBC production by kidneys

42. Goiter

43. Hyperthyroidism – Graves disease

44. Myxedema – before and after treatment

45. acomegaly

46. gigantism

47. cretinism

48. Pituitary dwarfism – 17 years old

49. Cushing’s Disease