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THE ENDOCRINE SYSTEM ALL ABOUT YOUR HORMONES!! He Pingping (he only reaches 2.4 feet), meets Bao Xishun (towering at 7.9 feet) tall! THE IMPORTANCE OF THE ENDOCRINE SYSTEM Body systems interact through the use of chemicals: hormones Chemicals produced in glands and secreted directly into the blood are endocrine hormones; carried by the circulatory system Hormones are classified according to their activation site Hormones: (Greek: hormon – to excite, set into motion) Are produced by glands and sent to the bloodstream Exert effect somewhere else in the body Are required in small amounts only Act in the metabolic pathway MINKOWSKI & MERING 1889 Removed dog pancreases What happened? Fatigued and lost wt. Ants were found in the kennels! Why? Increased glucose in urine Hormones are hard to study...no hormonal response works independently! CHEMICAL CONTROL SYSTEMS Provide integration and control of organs and tissues along with the nervous system Nervous system enables quick changes to environment Endocrine system designed to maintain control over longer durations The hypothalamus regulates the pituitary- the master gland- through nerve signals, but the pituitary, through other glands, affect the nerve activity of the hypothalamus IMPORTANT ENDOCRINE ORGAN TWO TYPES OF HORMONES Steroid hormones (made from cholesterol (testosterone, estrogen) and Protein hormones Steroids diffuse from capillaries into interstitial fluid, then into target cells Combine with receptor molecules in the cytoplasm Hormone-receptor complex then moves into nucleus and attaches to segment of chromatin with complementary shape Activates a gene to produce a specific protein STEROID HORMONES – SEX HORMONES PROTEIN HORMONES – INSULIN, GH Made up of chains of AA (insulin, GH) Combine with specific receptors on the cell membrane Some activate the enzyme adenylyl cyclase which causes cell to convert ATP into cyclic AMP (cyclic adenosine monophosphate) Cyclic AMP functions as a messenger, activating other enzymes in the cytoplasm to carry our normal functions PROTEIN HORMONES THE PITUITARY: THE MASTER GLAND Exercises control over other endocrine glands Two lobes: Anterior and Posterior Anterior – produces and stores hormones Posterior – stores hormones produced by hypothalamus HOMEWORK! Copy the chart on P 377 into your notes! Familiarize your self with the pituitary hormones! http://www.youtube.com/watch?v=8fh2HmdxQjQ HORMONES THAT AFFECT BLOOD SUGAR The Pancreas contains two types of cells Produces digestive enzymes Produces hormones – located in structures called the islets of Langerhans Over 2000 islets (each containing thousands of cells) are scattered throughout pancreas Islets contain alpha and beta cells which are responsible for the production of insulin and glucagon STORING AND RELEASING GLUCOSE! Insulin released when blood sugar levels increase insulin causes cells of muscles, liver, and other organs to become permeable to glucose. Liver converts glucose to glycogen Insulin causes decreases in blood sugar level Glucagon causes increase in blood sugar level (released when blood sugar levels are low, promotes conversion of glycogen to glucose. http://www.youtube.com/watch?v=NazZCu1lwOE&feature=related GREAT CANADIANS! Dr. Charles Best and Dr. Frederick Banting 1923 Nobel Prize for the discovery of Insulin (Best was excluded!!) Did not profit from the discovery...unheard of today! ADRENAL GLANDS Located above each kidney Inner gland – adrenal medulla medulla surrounded by outer casing (adrenal cortex), regulated by the nervous system hormones regulate the adrenal cortex Adrenal medulla produces two hormones (produced when cells within adrenal medulla are stimulated by sympathetic nerves in times of stress epinephrine norepinephrine FIGHT OR FLIGHT!! These two hormones initiate fight-or-flight biological responses blood sugar level rises glycogen converted to glucose ensures greater energy reserve available increase heart and breathing rates as well as cell metabolism blood vessels dilate = allowing more oxygen and nutrients to reach tissues irises dilate http://www.youtube.com/watch?v=RyP8L3qTW9 Q ADRENAL CORTEX Produces three different types of hormones Glucocorticoids Mineralocortiocoids one of the most important - Cortisol, increases level of amino acids in blood and helps in recovery of stress by being converted to glucose in liver, supplying more energy needed for repair or recovery by cells or participating in protein synthesis Salt and water balance – ALDOSTERONE! Sex hormones Small amounts! LONG TERM STRESS RESPONSE hypothalamus sends hormone to anterior lobe of pituitary stimulates pituitary to secrete corticotrophin (adrenocorticotropic hormone; ACTH) blood carries ACTH to target cells in adrenal cortex cells of adrenal cortex secrete mineralocorticoids and glucocorticoids (one of which is cortisol) these are carried to target cells in liver and muscles as cortisol levels rise, hypothalamus and pituitary production of regulatory hormones decreases SHORT TERM STRESS RESPONSE regulated by adrenal medulla epinephrine & norepinephrine aldosterone is one of most important mineralocorticoids increases sodium retention and water reabsorption by kidneys HOMEWORK! Copy Chart on p 382 into your notebook Do Q 1-7, Page 383 THYROID GLAND located at base of neck two important thyroid hormones (which regulate body metabolism, growth, and differentiation of tissues) thyroxine (T4) triiodothyronine (T3) HORMONES THAT AFFECT METABOLISM Three different glands affect metabolism thyroid gland helps regulate body metabolism (glucose oxidation rate) produces three hormones triiodothyronine, thyroxine, calcitonin parathyroid gland produces parathyroid hormone helps regulate calcium levels in blood and lower phosphate levels anterior pituitary gland produces growth hormones and regulatory hormones THYROID GLAND individuals who secrete higher levels of thyroxine oxidize sugars and other nutrients at a faster rate When glycogen stores are filled, excess sugar is converted to fat control of thyroid hormones is accomplished by negative feedback FEEDBACK LOOP... receptors in hypothalamus are activated if the metabolic rate decreases nerve cells secrete TRH (thyroid releasing hormone) this stimulates pituitary to release TSH (thyroid stimulating hormone) carried by blood to thyroid gland which then releases thyroxine which raises metabolism by stimulating sugar utilization by cells high levels of thyroxine cause pathway to be turned off, inhibiting release of TRH thyroxine contains calcitonin hormone acting on bone cells to lower level of calcium found in blood when inadequate amounts of iodine OH NO! when inadequate amounts of iodine are obtained from the diet, thyroid enlarges, producing a goiter. PARATHYROID GLANDS Four parathyroid glands hidden within larger thyroid gland Usually nerves or other hormones regulate the endocrine glands with the parathyroid glands being the exception These maintain homeostasis by responding directly to chemical changes in their immediate surroundings Raises calcium levels in the blood PTH (parathyroid hormone) also help activate vitamin D. (Low levels of vit D cause rickets!) RICKETS AND GOITERS... HUMAN GROWTH HORMONE (AKA SOMATOTROPIN) Too little = dwarfism Too much = gigantism Released by Ant. Pit. GH increases cell size in muscle cell and connective tissue by promoting Pro Synthesis (increasing Amino Acid uptake) Promotes fat burning Dec. Levels of GH with age HGH AND CONTROVERSY... Should you take it? Did Roger Clemens? HOMEWORK! Copy Chart on P. 387 Read 384-387, Do Nelson Biology 387 # 1-8 ADJUSTMENTS TO STRESS When initiator of stress is identified, endocrine and nervous systems make adjustments enabling body to cope with problem NERVOUS SYSTEM increases heart rate diverts blood to needed muscles activates reninangiotensin-aldosterone pathway in response to reduced blood flow to kidneys by increasing Na+ reabsorption, kidneys help maintain increased fluid volume thus helping to sustain adequate blood pressure during stress. Activation of hypothalamus causes increased release of antidiurectic hormone ADH which further increases water reabsorption from nephron to help maintain body fluids. ENDOCRINE SYSTEM hormones provide more sustained response to stimulus hormones provide more blood glucose to cope with elevated energy requirements insulin release inhibited regulation of blood pressure and volume WE HAVE A PROBLEM... Operating with elevated blood sugar, blood pressure, and heart rate creates problems for the body in terms of long-term stress PROSTAGLANDINS local responses to changes in immediate environment of cells detected by mediator cells these produce low concentrations of prostaglandins (hormones having pronounced effects in small localized areas) that tend to be absorbed by surrounding tissues (some absorbed by capillaries and carried in blood) Released during stress and allergic reactions STEROIDS... CHEMICALLY ENHANCED SPORTS PERFORMANCE Anabolic steroids – designed to mimic many of the muscle-building traits of the sex hormone testosterone In 1988 Olympic, Canadian sprinter Ben Johnson was disqualified for using Stanozolol There are a number of health risks linked to extended use of anabolic steroids: prematurely fuse growth plates in long bones of teens, thereby reducing height potential mood swings (e.g. rage) There are a myriad of drugs that affect the body sharpshooters use beta blockers that slow the heartbeat (helps to steady ain and calm jangled nerves) EPO and HGH are hard to detect b/c they are naturally occuring in the body HOMEWORK Read Chart P.391 Read Pages 388-392, Do Page 392 # 1-9 REPRODUCTIVE HORMONES MALE ANATOMY - REVIEW MALE REPRODUCTIVE SYSTEM male sex hormones androsterone and testosterone produced in interstitial cells (found between seminiferous cells) of testes testosterone stimulates spermatogenesis influences development of secondary male sexual characteristics at pituitary spermatogonia divide and differentiate into mature sperm cells stimulating maturation of testes and penis promotes development of facial and body hair, growth of larynx increases production of body oils FEEDBACK! Hypothalamus and pituitary gland control production of sperm and male sex hormones in testes Negative feedback systems ensure adequate numbers of sperm cells and constant levels of testosterone are maintained FEMALE ANATOMY - REVIEW FEMALE REPRODUCTIVE SYSTEM females follow complicated sexual cycle one egg matures ~ every month hormone levels fluctuate through reproductive years ending at menopause OOGENESIS AND OVULATION ovaries contain fibrous connective tissue and small groups of cells called follicles (two types of cells) primary oocyte granulosa cells primary oocyte contains 46 chromosomes, undergoes meiosis, transformed to mature oocyte (ovum) granulosa cells provide nutrients for oocyte each ovary contains ~ 400000 follicles at puberty, many follicles develop during each reproductive cycle, usually only one becomes dominant and reaches maturity OVULATION Hormone produced in pituitary controls follicle development Eventually a dominant follicle pushes outward, ballooning outer wall of ovary Secondary oocyte releases – ovulation Surrounding follicle cells remain within ovary and are transformed into corpus luteum, secreting hormones necessary for pregnancy. Secondary oocyte enters oviduct and begins Meiosis II MENSTRUAL CYCLE Takes about 28 days Divided into four distinct phases flow phase – shedding of endometrium (menstruation)(Day 1-5) follicular phase – development of follicles within ovary - hormone estrogen secreted (day 6-13) ovulatory phase – egg bursts from ovary and follicular cells differentiate into corpus luteum luteal phase – development of corpus luteum, secretion of estrogen and progesterone, prepares uterus for embryo and inhibits further ovulation (Day 15-28) HORMONAL CONTROL OF FEMALE REPRODUCTIVE SYSTEM Hypothalamus-pituitary complex regulates production of estrogen and progesterone Gonadotropins Female follicle-stimulating hormone (FSH) Luteinizing hormone (LH) Gonadotropins regulate control of hormones produced by ovaries Ovarian hormones regulate gonadotropins via negative feedback mechanisms GREAT VISUALS OF THE HORMONE CYCLES… http://www.youtube.com/watch?v=8_rfZ_qj1z4&fe ature=related HOW THE PILL WORKS… http://www.pbs.org/wgbh/amex/pill/sfeature/sf_cy cle.html