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ENDOCRINE SYSTEM ENDOCRINE SYSTEM Karen Lancour Patty Palmietto National Bio Rules National Event Committee Chairman Supervisor – A&P.

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Presentation on theme: "ENDOCRINE SYSTEM ENDOCRINE SYSTEM Karen Lancour Patty Palmietto National Bio Rules National Event Committee Chairman Supervisor – A&P."— Presentation transcript:

1 ENDOCRINE SYSTEM ENDOCRINE SYSTEM Karen Lancour Patty Palmietto National Bio Rules National Event Committee Chairman Supervisor – A&P

2 Endocrine System Major Endocrine Organs Hypothalamus Pituitary gland Pineal gland Thyroid gland Parathyroid gland Thymus Adrenal gland Pancreas Ovaries Testes


4 Feedback Mechanisms Stimulus change in homeostatic environment signal sent to CNS Response signal sent from CNS produce effect body returns to homeostasis

5 GLAND TYPES A. Exocrine gland Ducts Lumen and surfaces B. Endocrine gland Chemical messengers Blood stream

6 Hormones specific chemical compound produced by a specific tissue of the body released in the body fluids carried to a distant target tissue affects a pre-existing mechanism effective is small amounts.

7 Hormones Chemical messenger Secreted by endocrine gland Specific to target Activate cellular change Of 4 different chemical types

8 Classes of Hormones: peptides – short chains of amino acids (most hormones) pituitary, parathyroid, heart, stomach, liver & kidneys amines - derived from tyrosine and secreted by thyroid and adrenal cortex steroids - lipids derived from cholesterol secreted by the gonads, adrenal cortex, and placenta eicosanoid - Produced from 20-carbon fatty acid, arachadonic acid, produced in all cells except RBCs - Prostaglandins and leukotrienes

9 Peptide/Protein Hormones Most common hormone translated, packaged, & sent Hydrophilic/Lipophobic Bind surface receptors at target Binding mediates signal transduction/2nd messenger system

10 Protein/Peptide Hormones Hydrophilic Large Can't fit through membrane Second messenger mechanism of action Most hormones Example: Insulin

11 peptide and amines Protein hormones (1 st messengers) - bind to receptor on target cell triggering 2 nd messenger to affect cells activity hormone (1st messenger) does not enter the cell but binds to receptor on the plasma membrane receptors hormone-receptor complex activates G protein generates chemical signal (2nd messenger) – most common is cAMP and IP3 2nd messenger chemical signal activates other intracellular chemicals to produce response in target cell

12 Amine Synthesized from a single amino acid Melatonin from tryptophan Thyroid hormone from tyrosine Catecholamines (EPI, DA) from tyrosine

13 Eicosanoid Produced from 20-carbon fatty acid, arachadonic acid Produced in all cells except RBCs 2nd messenger Prostaglandins and leukotrienes inflammation

14 Hormone + Receptor

15 Steroid Hormones Small Hydrophobic/Lipophilic Travel in blood w/carrier Cytoplasmic or nuclear receptors change protein synthesis Example: estradiol

16 Steroid Hormones Steroid hormones - bind to receptors within target cell and influence cell activity by acting on specific genes hormone diffuses freely into cell where cytoplasmic and/ or nuclear proteins serve as receptors hormone binds to receptor (hormone-receptor complex) complex bonds to steroid response element (sections of DNA receptive to the hormone-receptor complex hormone-receptor complex acts as transcription factor to turn target genes on or off

17 Hormone + Receptor

18 The H-P-A Hypothalamic-Pituitary Axis Most feedback loops run through this axis HPA mediates growth, metabolism, stress response, reproduction. is secondarily in charge of almost everything else.

19 Neurosecretory Cells 1. Specialized neurons Synthesize and secrete hormones 2. Extend from HYPOTHALAMUS to POSTERIOR PITUITARY

20 Neurosecretory cells in Hypothalamus Nuclei synthesize and secrete hormones Neuronal connection to POSTERIOR pituitary Antidiuretic Hormone (ADH), Oxytocin

21 Hypothalamus (general) Connection to pituitary Neuronal to POSTERIOR PITUITARY Endocrine to ANTERIOR PITUITARY RH = Pituitary releasing hormones RIH = Pituitary release inhibiting hormones

22 Hypothalamus Secretes regulatory homones RH RIH "Directs" pituitary

23 STIMULUS Hypothalamus Releasing Hormone (Release-Inhibiting Hormone) Pituitary Stimulating Hormone Gland Hormone Target

24 Hypothalamic Hormomes Release Inhibiting Hormones Somatostatin Prolactin release inhibiting hormone-PIH Releasing Hormones Thyrotropin releasing hormone-TRH Growth hormone releasing hormone-GHRH

25 Posterior Pituitary Hormones Manufactured in Hypothalamus, released from Post. Pit. Oxytocin Target = smooth ms. Uterus and Breast (&brain) Function = labor and delivery, milk ejection,(pair bonding) ADH (Vasopressin AVP) Target = kidneys Function = water reabsorption

26 Pituitary gland MASTER GLAND Anterior and posterior portions 1.Posterior connected to hypothalamus by infundibulum 2.Anterior connected via blood stream

27 Anterior Pituitary Hormones HORMONETARGETFUNCTION Thyroid (TSH) Stimulating Thyroid glandTH synthesis & release Growth (GH)Many tissuesgrowth Adrenocortico- Tropin (ACTH) Adrenal cortexCortisol release (androgens) Prolactin (Prl)BreastMilk production Follicle (FSH)GonadsEgg/sperm prod. Luteinizing (LH) GonadsSex hormones

28 Control of Endocrine Function A. Positive B. or Negative Feedback mechanisms Self-regulating system

29 STIMULUS Hypothalamus Releasing Hormone (Release-Inhibiting Hormone) Pituitary Stimulating Hormone Gland Hormone Target

30 Positive Feedback Not common Classic example: Action of OXYTOCIN on uterine muscle during birth.

31 Positive Feedback Baby pushes on cervix Nervous signal to Hypothalamus Hypothal. manufactures OXY OXY transported to POSTERIOR PITUITARY & released OXY stimulates uterine contraction Loop stops when baby leaves birth canal

32 Negative Feedback Most common control mechanism Level of hormone in blood or bodys return to homeostasis shuts off loop at hypothalamus and pituitary

33 Negative Feedback: Thyroid

34 Basic Structure of Feedback Loop Environmental Stimulus Stimulates Control Center (Brain- hypothalamus) Hypothalamic hormones stimulate Pituitary Pituitary hormone stimulate Target area Target area produces change Change acts negatively or positively on the cycle.

35 Specific Endocrine Events A. Thyroid Hormone B. Growth Hormone C. Adrenal Cortex Hormones D. Sex Steroids

36 Endocrine Disorders Hyposecretion disorders are caused by too little hormone – they can be treated by addition of the hormone Hypersecretion disorders are caused by too much hormone – these are much harder to treat

37 Thyroid Hormone T3 & T4 stim. Or environmental stim. Hypothalamus TRH stim. Anterior Pituitary TSH stim. Thyroid T3 & T4 shuts off TRH and TSH production

38 Thyroid Problems What would happen if the thyroid could no longer produce T3 and T4? No negative feedback to hypothalamus and anterior pituitary

39 Hypersecretion of TSH or TH

40 Hyposecretion of TH

41 Growth Hormone Stimulus = Tissue growth/ repair Hypothalamus releases GHRH Anterior Pituitary releases GH Protein synthesis, growth, etc. GH and release of somatostatin shuts off GHRH and GH release

42 GH as Juvenile

43 Adrenal Gland Adrenal gland located atop kidney Outer part = cortex Secretes Cortisol (stress), Androgens, Aldosterone (electrolytes) Inner part = medulla SNS control Secretes EPI & NEPI (fight or flight)

44 Adrenal Insufficiency Addisons disease--hyposecretion of cortisol JFK Darkened skin (ACTH mimics MSH) Weight loss, hypoglycemia Find the anomaly in the feedback loop. Inability to handle stress

45 Sex Steroids Stimulus = low circulating T or E Hypothalamus = GnRH Anterior Pituitary = FSH & LH Gonads produce T and E High T and E shut off GnRH and FSH/LH

46 Too many steroids

47 Diseases of the Endocrine System Diabetes – increased levels of glucose in blood Diabetes – increased levels of glucose in blood Hypoglycemia - low blood sugar Hypoglycemia - low blood sugar Graves Disease – overactive thyroid Graves Disease – overactive thyroid Goiter – enlarged thyroid gland Goiter – enlarged thyroid gland

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