Function of the Endocrine System Coordinate and integrate functions to maintain homeostasis Hormones are released into the bloodstream and eventually act on cells called target cells Endocrine Glands ID: 1048236
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1. Chapter 11Endocrine System
2. Function of the Endocrine SystemCoordinate and integrate functions to maintain homeostasisHormones are released into the bloodstream and eventually act on cells called target cells
3. Endocrine GlandsEndocrine glands make hormonesHormoneschemical messenger secreted into bloodstream, stimulates response in another tissue or organHormones use the circulatory system to reach their targetDo not confuse with exocrine glands which has secretions that go through a duct
4. Blood levels of hormones: Most are controlled by negative feedback systemsVary only within a narrow desirable rangeHormones are synthesized and released in response to three basic mechanisms.Humoral: changes and substances in the blood (glucose or K+)Neural: stimulation from the nervous system via neurotransmitters. Hormonal stimuli: organ or gland releases a hormone that stimulates the release of another hormone from another glands or organ.Control of Hormone Release
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6. HypothalamusControls many endocrine glands: regulates the endocrine system through it’s direct connection to the pituitary glandThe hypothalamus controls basic functions such as: body temperature, blood pressure, growth and development ,reproduction, electrolyte balance and water regulation.It accomplishes this by producing both releasing and inhibiting hormones that influence the anterior pituitary gland.
7. Pituitary GlandAbout size of a grapeLocated at base of brainConnected to the hypothalamushoused in sella turcica of sphenoid boneAnterior lobe and posterior lobeAlso known as the master gland
8. Anterior Lobe – PituitaryGrowth hormone (GH) or somatotropinProlactin hormone (PRL)Thyroid-stimulating hormone (TSH)Adrenocorticotropic hormone (ACTH)Follicle-stimulating hormone (FSH)Luteinizing hormone (LH)Interstitial cell-stimulating hormone (ICSH) ONLY IN MALES
9. The AdenohypophysisGrowth hormone (GH)Causes the body to growProlactin (PRL)Stimulates lactation (milk production) in femalesStimulates lacrimation (desire to cry) Decreased in adolescent males so it decreases desire to cryThyroid Stimulating Hormone (TSH)Causes the thyroid gland to release thyroid hormone9
10. The AdenhypophysisAdrenocorticotropic hormone (ACTH)Acts on adrenal cortex to stimulate the release of cortisol Helps people cope with stressFSH and LH are called gonadotropins because they act on the gonads. They regulate reproductive function.Follicle-stimulating hormone (FSH) Present in males and females, affects bothStimulates maturation of sex cellsLuteinizing hormone (LH)Induces ovulation in femalesInduces testosterone in males10
11. Intermediate Lobe – PituitaryFew cells along borders of posterior and anterior lobes; so small that it’s often just associated with the anterior lobeMelanocyte-stimulating hormone (MSH)Darkens skin pigmentationIncreases during pregnancy
12. Study Tip to remember the hormones secreted by the anterior pituitary gland“Melons grow and produce through late fall” stands for the hormones made in the anterior pituitary. Melanocyte stimulating hormone (MSH)Growth Hormone (GH) Adrenal corticotropic Hormone (ACTH)Prolactin (PRL)Thyroid stimulating hormone (TSH)Luteinizing Hormone (LH) Follicle stimulating Hormone (FSH)12
13. Posterior Lobe – PituitaryVasopressin converts to antidiuretic hormone (ADH) in the bloodstreamSignals kidneys to increase water reabsorption http://science.howstuffworks.com/life/human-biology/hangover2.htmOxytocinChildbirth contractionsPitocin
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15. Pineal GlandLocated on the roof of the third ventricle in the brainMelatonin
16. Thyroid GlandsLocated in neck close to the cricoid cartilage (Adam’s apple)Regulates body metabolismThyroxine (T4)Triiodothyronine (T3)Acts on most cells of the bodyIncreases metabolic rate Controlled by hormonal mechanismIodine is needed to make THCalcitoninLowers blood calcium levels; especially secreted in childrenSlows osteoclasts to allow osteoblasts to deposit bone in the skeleton.
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18. Parathyroid GlandsFour glands size of grains of riceAttached to the posterior surface of the thyroid glandMaintains calcium-phosphorus balanceParathyroid hormone (PTH)PTH and calcitoninAntagonistic effectsCalcitonin raisesParathormone decreases
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20. THYMUS GLANDGland that sits under the sternum, on top of the heart.It is like an nursery incubator for one type of white blood cell (T cell). They go there to mature. The thymus gland also produces hormones (thymosins) to help them mature. This gland is mostly active in children under the age of three. It shrivels up in an adult.20
21. Adrenal GlandsLocated on top of each kidneyHave a cortex and a medullaACTH from the pituitary gland stimulated activity of the cortex
22. Adrenal MedullaEpinephrine or adrenalin (epinephrine “above the kidney”; Greek). Powerful cardiac stimulantNorephinephrineResponds to the sympathetic nervous systemFight-or-flight hormones
23. Adrenal CortexMineralocorticoidsAldosterone -Sodium/water reabsorbedGlucocorticoidsCortisol – secreted in response to ACTH from the pituitary gland. Cortisol stimulates fat and protein catabolism (break down) to use for gluconeogenesis.The name glucocorticoid (glucose + cortex + steroid) derives from their role in the raising glucose levels, their synthesis in the adrenal cortex, and their steroidal structure. They suppress the immune system (they are anti-inflammatory).Cortisol (also known as hydrocortisone) is one of the most important glucocorticoids.Androgens Male sex hormones (Androgens)Female sex hormones (estrogen)
24. Effects of Increased GlucocorticoidsCortisol is called an anti-stress hormone because it does several things: Stimulates protein and fat catabolism (breakdown)The breakdown products are then taken to the liver for gluconeogenesis in the liverInhibits glucose uptake by the body but not the brainIt elevates blood glucose (diabetogenic effect)It suppresses the immune responseThat means it is an anti-inflammatory agentIt is prescribed as a medicine to suppress inflammation and the immune system. 24
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27. Pancreas Located behind stomachExocrine and endocrine functionsInsulinSignals most body cells to take up glucose from the bloodPromotes storage of glucose as glycogen in liverLowers blood sugarGlucagonSignals liver to break down glycogen into glucoseRaises blood sugar
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29. Gonads Also called sex glandsFemaleOvariesMaleTestes
30. Gonads – HormonesFemale EstrogenFemale secondary sex characteristicsProgesteronePrepares uterus for pregnancy by causing enlargement of arteries supplying blood to the endometrium and growth of endometrial glandsMaleTestosteronePromotes the formation of spermMaintains secondary sex characteristicsTestes are the primary sex organs in the male, NOT the penis
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32. Effects of Aging Affects nearly every glandBlood levels of some hormones increase while others decreaseAffects the homeostasis of the body
33. Endocrine System DisordersA number of factors can cause problemsDisease of the glandAutoimmune causesInfectionsDietary deficienciesSigns and symptoms usually do to hyper- or hypoactivity of the glands
34. Pituitary DisordersHypersecretion of GH in childrenGigantism (overall growth)Hypersecretion of GH in adultsAcromegaly: enlarged hands and feet, and big chin, nose, and foreheadHyposecretion of GHPituitary dwarfismProportions are normal, overall size is small34
35. GigantismExcessive growth hormone before the growth plates fuse.Good for basketball Bad for horse racing.
36. Gigantism36Robert Wadlow 8’11”Sandy Allen 7’7”
37. AcromegalyTo much GH usually after the growth plates have fused.Results in great wrestlers.Beware the Pituitary Tumor.
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39. DANGERS OF STEROIDSSteroids that weightlifters take are synthetic testosterone, and they are taken in doses 100x larger than a prescription, so they are dangerous. Although they increase muscle size, they increase rage and aggression, cause kidney and liver disease, cancer, severe acne, high blood pressure, high cholesterol, impotence, baldness, decreases the size of testicles and causes a low sperm count and sterility.In males, it causes baldness and increases the breasts.In women it causes hair on their face and chest, and decreases the breasts.In children, it stunts the growth.In everyone, they can shorten the life span by several decades. 39
40. DwarfismHyposecretion of GH May require GH replacement therapy
41. Pituitary Dwarfism41
42. Pituitary DisordersDiabetes insipidus (water thirsty)Not enough ADH (anti-diuretic hormone; a diuretic takes out excess fluid from the body).An anti-diuretic keeps the water in the bodyBecause they lack ADH, the person urinates frequently (polyuria), so they are thirsty and drink a lot of water (polydipsia). Their blood glucose is normal. The synthetic form of ADH is vasopressin (a medicine). It is used to raise low blood pressure.42
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44. Thyroid DisordersAll cells respond to thyroid hormone, increasing their metabolic rate (heart speeds up, beats with greater force, more nutrients are used, etc). Too much thyroid hormone is hyperthyroidism; these people are thin and active.Grave’s disease When levels of TH are too low, it is called hypothyroidism; these people are overweight, move slowly, have no energy.Hashimoto’s MyxedemaCretinism- hypothyroidism in children44
45. GOITER This is usually caused by too little iodine in diet. That’s why salt is iodized. Iodine is only found in seafood, so if salt wasn’t iodized, a lot of people wouldn’t get enough iodine, and there would be a lot of goiters. There are more problems with the thyroid gland than any other organ. 45
46. Goiter46All you need is a pinch per day of salt. If you can’t have salt, you can take iodine drops.
47. Endemic goiterGoiter = enlarged thyroid glandresults from dietary iodine deficiency.Can’t produce TH, no feedback to Pituitary TSHThis causes hypertrophy of the thyroid gland.
48. Toxic goiter (Graves disease)Antibodies mimic TSH causing ’d TH to be released, Excessive Thyroxin levels elevated metabolism heart rateweight lossnervousness exophthalmos (bulging eyes)ANS induced sweating.
49. Disorders – ParathyroidHyperparathyroidismIncreased blood calciumHypoparathyroidismDecreased blood calciumTetany
50. Adrenal Gland DisordersCushing’s syndrome/DiseaseHypersecretion of cortisol High blood glucoseHigh blood pressureFeatures of the opposite sexRound “moon” face and “buffalo hump”Addison’s diseaseHyposecretion of cortisolLow blood glucoseLow blood pressure resultsAlso get hyperpigmentation 50
51. Cushing Disease
52. Cushing Disease
53. Addison's DiseaseResults from a hyposecretion of ACTH or an autoimmune disease that damages the adrenals. Results in decreased glucocorticoids and mineralocorticoid release.Results in hypotension and hypoglycemia Corticosteroid replacement therapy
54. Diabetes MellitusPancreatic disorderDecreased secretion of insulin from the islets of Langerhans cells or by the ineffective use of insulinType I and Type II diabetes
55. Type I diabetes (insulin dependent, develops in children) Destruction of pancreatic islets by autoimmune disorders. Need insulin injections daily throughout life.Type II diabetes (not insulin dependent, develops in adults)Consequence of obesity: cells are less sensitive to insulin. Initially treated with diet and exercise.Oral medicines or injected insulin may be needed.