17%20and%2018%20Endocirne0.ppt

Chapter 17 and 18 Functional Organization of the Endocrine System and Glands Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the ?Normal? or ?Slide Sorter? views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. Hormonal Communication Characteristics of the Endocrine System Glands that secrete chemical messengers (hormones) into circulatory system Hormone characteristics Produced in small quantities Secreted into intercellular space Transported some distance in circulatory system Acts on target tissues elsewhere in body Regulate activities of body structures Ligands: more general term for chemical signals Comparison of Nervous and Endocrine Systems Similarities Both systems associated with the brain May use same chemical messenger as neurotransmitter and hormone. Two systems are cooperative Nervous system secretes neuroendocrine peptides, or neurohormones, into circulatory system Some parts of endocrine system innervated directly by nervous system Differences Mode of transport Axon Blood Speed of response Nervous ? instant/milliseconds Endocrine ? delayed/seconds Duration of response Nervous ? milliseconds/seconds Endocrine ? minutes/days Amplitude vs. frequency 17-* Control of Hormone Secretion Most hormones controlled by negative feedback systems Most hormones are not secreted at constant rate, but their secretion is regulated by three different methods The action of a substance other than a hormone on an endocrine gland. Neural control of endocrine gland. Control of secretory activity of one endocrine gland by hormone or neurohormone secreted by another endocrine gland Negative Feedback Control by Humoral Stimuli Blood-borne molecules stimulate release Control by Neural Stimuli APs stimulate release Control by Hormonal Stimuli Hormones cause other hormones to be released. Hypothalamus stimulates the release of tropic hormones from anterior pituitary. Target Tissue Specificity and Response Portion of molecule where hormone binds is called binding site. If the molecule is a receptor (like in a cell membrane) the binding site is called a receptor site hormone/receptor site is specific; e.g., epinephrine cannot bind to the receptor site for insulin. The purpose of binding to target tissue is to elicit a response by the target cell. Classes of Receptors: Lipid Soluble Lipid-soluble hormones bind to nuclear receptors Hormones Lipid soluble and relatively small molecules; pass through the plasma membrane React either with enzymes in the cytoplasm or with DNA to cause transcription and translation Thyroid hormones, testosterone, estrogen, progesterone, aldosterone, and cortisol Classes of Receptors: Water Soluble Water-soluble hormones bind to membrane-bound receptors: integral proteins with receptor site at extracellular surface. Interact with hormones that cannot pass through the plasma membrane. Hormones Water-soluble or large-molecular-weight hormones. Attachment of hormone causes intracellular reaction. Large proteins, glycoproteins, polypeptides; smaller molecules like epinephrine and norepinephrine Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the ?Normal? or ?Slide Sorter? views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. Hypothalamus and Pituitary Glands Posterior pituitary (neurohypophysis): extension of the nervous system via the infundibulum Anterior pituitary (adenohypophysis) Endocrine System: Pituitary Gland Endocrine System: Anterior Pituitary and Hypothalamus Tropins or tropic hormones: hormones that regulate the hormone secretions of target endocrine tissues. Releasing hormones: GHRH. Growth hormone-releasing hormone. Causes the anterior pituitary to release growth hormone. TRH. Thyrotropin-releasing hormone. Causes the anterior pituitary to release thyroid-stimulating hormone (TSH). CRH. Corticotropin-releasing hormone. Causes anterior pituitary to produce adrenocorticotropic hormone. GnRH. Gonadotropin-releasing hormone. Causes anterior pituitary to produce FSH (follicle stimulating hormone) and LH (luteinizing hormone). PRH. Prolactin-releasing hormone. Causes the anterior pituitary to release prolactin. Inhibiting hormones: GHIH. Growth hormone-inhibiting hormone, somatostatin. Causes the anterior pituitary to decrease release of growth hormone. PIH. Prolactin-inhibiting hormone. Causes the anterior pituitary to decrease release of prolactin. Endocrine System: Releasing and Inhibiting Hormones Endocrine System: Posterior Pituitary and Hypothalamus Endocrine System: ADH Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the ?Normal? or ?Slide Sorter? views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. Hormonal Communication Endocrine System: Oxytocin Endocrine System: GH Endocrine System: Thyroid Hormones Endocrine System: Adrenergics Endocrine System: Cortisol Endocrine System: Glucose and Insulin Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the ?Normal? or ?Slide Sorter? views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. Pancreas