Study Guide Exam II Chapter 18 The Endocrine System An Overview 1 Define an endocrine gland and list the major endocrine glands of the body and their locations exocrine gland secrete their products into ducts that carry the secretions into the lumen of an organ or to the outer surface of the body endocrine gland secrete products into the interstitial fluid surrounding the secretory cells throughout the body from interestitial fluid diffuse into blood capillaries and blood carries them to taret cells depend on cardiovascular system to distribute proucts most vascularized tissues of body major endocrine glands of the body pituitary brain thyroid neck below the pharynx parathyroid surface of thyroid adrenal pair of ducts located above the kidneys pineal brain organs tissues that secrete hormones o o o o o o hypothalmus thymus pancreas ovaries testes kidneys stomach liver small intestine skin heart adipose tissue placenta Hormones 2 Define a hormone and describe the chemical categories of hormones Hormone mediator molecule that is released in one part of the body but reulates the activity of cells in other parts of the body most enter interstitial fluid then the bloodstream to be delivered throughout the body Chemical Categories of Hormones o Water Soluble Hormones Amine retain amino group NH3 Catecholamines epinephrine norepinephrine dopamine synthezied by modifying the amino acid tyrosine histamine synthesized from histadine by mast cells and platelets Serotonin and mealtonin from trytophan Peptide Protein amino acid polymers Ex Peptide Antidiuretic and Oxytocin Protein TSH has attached carbohydrate groups glycoprotein Eicosanoid derived from arachidonic acid Prostaglamdins and Leukotrienes important local hormones Steroid derived from chol Thyroid synthezied by attching iodine to amino acid tyrosine two benzene rings within a T3 or T4 make very lipid soluble Nitric Oxide NO both hormone and neurotransmitter synthesis catalyzed by enzyme NO synthase o Lipid soluble Hormones 3 Explain the relationship of hormones to target cells and the types of changes that result in target cells in response to hormone stimulation responsiveness depends on hormons concentration in the blood abundance of target cells hormone receptors and inflences exerted by other hormones reponds quicker with highler level or hormone and or receptors 4 Describe the second messenger systems used by amino acid based hormones not lipid soluble first messanger receptor on the outer surface of the plasma membrane activates second messanger cyclic AMP inside cell where specific hormone stimulated response takes place 1 diffuses from blood through interstitial fluid binds to receptor at exterior surface of target cell hormone receptor complex activates G protein to activate Adenylate cyclase 2 Adenylate conversts ATP to cAMP in the cytosol 3 cAMP activates protein kinase converst ATP to ADP 4 activated protein kinases phosphorylate cellular proteins 5 phosphorylated proteins cause reactions that produce physiological responses 6 Phosphodieterase inactivates cAMP cells response is turned off unless new hormone moelcules continue to bind to receptors 5 Explain the mechanism of intracellular activation used by steroid hormones and thyroid hormone bind to receptors within target cell 1 diffuses from blood through interestitial fluid through lipid bilayer into plasma membrane 2 hormone binds to activates receptors and alters gene expression turns specific genes of the nuclear DNA on or off 3 DNA is transcribed new mRNA forms leaves the nucleus and enters cytosol directs synthesis of new protein 4 New proteins alter cells activity cause response of hormone 6 Examine the factors that determine target cell activation and compare how the cell uses up regulation and down regulation to alter its responsiveness to hormones influence target cells by chemically binding to specific protein receptors only target cells for a given hormone have receptors that bind and recognize that hormone Down regulation if a hormone is present in excess number of target cell receptors may decrease makes target cell LESS sensitive to hormone Up regulation hormone is deficient number of receptors increase makes target cells more sensitive to a hormone 7 Identify the factors that affect circulating hormone concentration and the differences in the time required for the effects of hormones to be seen in target cells circulating hormones pass from secretory cells into the interstitial fluid then the blood linger in the blood longer and are inactivated by the liver and secreted by the kidneys 8 Underscore the three types of hormone interaction on target cells permissive effect stimulous of second hormone increses number of receptors for the other hormone and sometimes promotes synthesis Antagonistic effects when one hormone opposes the actions of another hormone synergistic effect when the effect of two hormones acting together is greater or more extensive than the effect of each hormone acting alone not one hormone would be sufficient for the job 9 Discuss the three types of stimuli that promote or inhibit the release of hormones and the effect of nervous system modulation secretion regulated by o o o signals from nervous system chemical changes in the blood other hormones Major Endocrine Organs 10 List the hormones produced by the major endocrine organs the factors controlling their release and their effects on target cells Endocrine Gland Hormone Target Tissue Anterior Pituitary Gland Human Growth Hormone HGH Liver and other tissues Principal Actions Control of Secretion Stimulates liver muscle cartilage bone and other tissues to synthesize and secrete insulinlike growth factors IGFs which promote growth of body cells protein synthesis tissue repair lipolysis and elevation of blood glucose concentration Stimulates synthesis of thyroid hormones by thyroid gland Females initiates development of oocytes and induces ovarian secretion of estrogens Males stimulates sperm production Females secretion of estrogens and progesterone ovulation and formation of corpus luteum Males stimulates production of testosterone Stimulates secretion of Glucocorticoids mainly cortisol by adrenal cortex Thyroid Stimulating Hormone TSH Thyroid Gland Follicle Stimulating Hormone FSH Ovaries and Testes Lutenizing Hormone LH Ovaries and Testes Prolactin PRL Mammary Glands Promotes milk production Adrenocorticotropic hormone ACTH Adrenal Cortex Posterior Pituitary Gland Oxytocin OT
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