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Courtney Llinares & Brenda Yik

Courtney Llinares & Brenda Yik. Hormones and the Endocrine System. The endocrine system and hormones. What are hormones? Molecules that are diffused throughout the body to communicate various regulatory messages to specific target cells What is the endocrine system?

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Courtney Llinares & Brenda Yik

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  1. Courtney Llinares & Brenda Yik Hormones and theEndocrine System

  2. The endocrine system and hormones • What are hormones? • Molecules that are diffused throughout the body to communicate various regulatory messages to specific target cells • What is the endocrine system? • One of two major bodily communication systems (the other being the nervous system)

  3. Types of cellular communications • Intercellular communications: different ways signals are sent between animal cells • Types of intercellular communications are endocrine, paracrine, autocrine synaptic, and neuroendocrine sigaling • Extracellular communications: • Pheromones

  4. Intercellular communication by secreted molecules Blood vessel Response (a) Endocrine signaling Response (b) Paracrine signaling Response (c) Autocrine signaling Synapse Neuron Response (d) Synaptic signaling Neurosecretory cell Blood vessel Response (e) Neuroendocrine signaling

  5. Early endocrine/hormonal systemsCnidarians: Hydra • Endocrine system was not yet developed, but evidence has shown neurohormones in effect • Contains neuropeptides that stimulate processes

  6. Early Hormones/Endocrine system Annelids: Nereis • Marine worm • Long ventral nerve cord with a segmented ganglion • Produces the peptide hormone neredine, in the ganglion (early brain)

  7. Early Hormones/Endocrine systemArthropods: Butterfly • Has an endocrine system and hormones for molting, development, and more • A brain hormone stimulates release of ecdysone from the prothoracic glands

  8. Hormones/Endocrine system Mammals: Humans • Have fully developed endocrine system with a variety of functional hormones • The endocrine systems is made of eight functional glands: • Hypothalamus • Pituitary • Thyroid • Parathyroids • Thymus • Adrenals • Gonads

  9. Major endocrine glands: Hypothalamus Pineal gland Pituitary gland Organs containing endocrine cells: Thyroid gland Thymus Parathyroid glands Heart Liver Adrenal glands Stomach Pancreas Kidney Testes Small intestine Kidney Ovaries

  10. Chemical classes of hormones • Three classes of hormones: • Polypeptides • Steroids • Amines • Hormones vary in solubility in aqueous and lipid environments • Water soluble hormones: polypeptides and most amines • Lipid soluble hormones: steroids

  11. Hormones differ in form and solubility Water-soluble Lipid-soluble 0.8 nm Polypeptide: Insulin Steroid: Cortisol Amine: Epinephrine Amine: Thyroxine

  12. Effects of hormones • Many hormones cause more than one type of cellular response • Example: Epinephrine triggers glycogen breakdown in the liver, increases blood flow to many skeletal muscles, and more simultaneously • Signaling by local regulators: local regulators are molecules that send chemical signals in seconds unlike hormones, but have the same pathways as hormones Ex: Growth factors, and nitric oxide

  13. Feedback Regulation • In simple endocrine pathways cells responds directly to and internal or environmental stimulus by secreting certain hormones • These responses link back to deduce the initial stimulus (negative feedback) or enhance the initial stimulus (positive feedback)

  14. Signal Transduction Pathway Example – Stimulus Low blood glucose Pancreas alpha cells secretes glucagon Endocrine cell Negative feedback Blood vessel Target cells Liver Glycogen breakdown,glucose release into blood Response

  15. Antagonistic Hormones and Diabetes • Insulin and glucagon are antagonistic hormones that help maintain homeostasis in blood glucose levels • Diabetes mellitus: disorder caused by insulin level or response abnormalities • Treatment involves insulin injections, lifestyle changes, or medication

  16. Coordination of Endocrine and Nervous systems • Hypothalamus connects the nervous and endocrine systems • Pituitary gland receives signals from the hypothalamus for various hormone excretions

  17. Cerebrum Thalamus Pineal gland Hypothalamus = brain Cerebellum Pituitary gland Spinal cord Endocrine glands in the human brain Hypothalamus Posterior pituitary Anterior pituitary

  18. Thyroid Regulation • In thyroid regulation a hormone cascade pathway occurs where a hormone stimulates the release many other hormones • The last of the secreted hormones activates a nonendocrine target cell

  19. Pathway Example A hormone casade pathway Stimulus Cold Sensoryneuron – Hypothalamus secretesthyrotropin-releasinghormone (TRH ) Neurosecretorycell Bloodvessel – Anterior pituitary secretes thyroid-stimulatinghormone (TSHor thyrotropin ) Negative feedback Thyroid gland secretes thyroid hormone (T3 and T4 ) Targetcells Body tissues Increased cellularmetabolism Response

  20. Disorders of Thyroid Function • Hypothyroidism occurs when there is low secretion of thyroid hormones -Treatment: -Levothyroxine medication commonly used to replace lacking thyroid hormone

  21. Disorders of Thyroid Function Continued • In humans, hyperthyroidism is condition in which thyroid gland produces excessive amount of thyroid hormone • Treatment: -Antithyroid medications -Radioactive iodine

  22. Tropic and Nontropic Hormones • Tropic hormones: regulate the function of other endocrine cells or glands Examples: -TSH (thyroid-stimulating hormones) regulate the thyroid gland -Follicle-stimulation hormone • Growth hormones: stimulates growth through tropic and nontropic effects

  23. Parathyroid Hormone and Vitamin D • Parathyroid glands release the parathyroid hormone (PTH) • Maintains homeostatic control of blood calcium levels directly and indirectly • PTH synthesizes Vitamin D in the kidneys which acts directly by activating the release of Ca²⁺ • calcitonin is a hormone that inhibits bone absorption and enhances calcium release by the kidney

  24. Coordination of the Endocrine and Reproductive system • Gonadal sex hormones: affect growth, development, reproductive cycles, and sexual behavior -The gonads produce and secrete three major categories of steroid hormones (androgens, estrogens, and progestins)

  25. Bibliography • "Biology:." Google Books. Web. 25 Mar. 2012. <http://books.google.com/books?id=7W3OlS7QUMoC>. • Board, A.D.A.M. Editorial. "Causes, Incidence, and Risk Factors." Hyperthyroidism. U.S. National Library of Medicine, 18 Nov. 0000. Web. 25 Mar. 2012. <http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001396/>. • Board, A.D.A.M. Editorial. "Causes, Incidence, and Risk Factors." Hypothyroidism. U.S. National Library of Medicine, 18 Nov. 0000. Web. 25 Mar. 2012. <http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001393/>. • "THE ENDOCRINE SYSTEM." The Endocrine System. Web. 25 Mar. 2012. <http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookendocr.html>. • "The Hormone Foundation." The Endocrine System & Types of Hormones: An Overview. Web. 25 Mar. 2012. <http://www.hormone.org/endocrine_system.cfm>. • "Integrative and Comparative Biology." Endocrine-like Signaling in Cnidarians: Current Understanding and Implications for Ecophysiology. Web. 25 Mar. 2012. <http://icb.oxfordjournals.org/content/45/1/201.full>. • "National Diabetes InformationClearinghouse (NDIC)." What I Need to Know about Diabetes Medicines. Web. 25 Mar. 2012. <http://diabetes.niddk.nih.gov/dm/pubs/medicines_ez/index.aspx>. • "The NP Mom." The NP Mom. Web. 25 Mar. 2012. <http://thenpmom.wordpress.com/2012/01/12/im-running-and-i-cant-stop-hyperthyroidism/>. • "Read What Your Physician Is Reading on Medscape." EMedicineHealth. Web. 25 Mar. 2012. <http://www.emedicinehealth.com/anatomy_of_the_endocrine_system/article_em.htm>. • Reece, Jane B., and Neil A. Campbell. Campbell Biology / Jane B. Reece ... [et Al.]. Boston: Benjamin Cummings, 2011. Print. • "Subclinical Hypothyroidism." , September 22/29, 2010, Pluta Et Al. 304 (12): 1402. Web. 25 Mar. 2012. <http://jama.ama-assn.org/content/304/12/1402.full>. • "Subclinical Hypothyroidism." , September 22/29, 2010, Pluta Et Al. 304 (12): 1402. Web. 25 Mar. 2012. <http://jama.ama-assn.org/content/304/12/1402.full>. • "Supplemental Content." National Center for Biotechnology Information. U.S. National Library of Medicine. Web. 25 Mar. 2012. <http://www.ncbi.nlm.nih.gov/pubmed/18652396>. • "Untitled 1." Lander University ITS. Web. 25 Mar. 2012. <http://lanwebs.lander.edu/faculty/rsfox/invertebrates/nereis.html>.

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