Endocrine SystemThe Endocrine SystemTypes of HormonesHormones as Chemical MessengersHormone Interaction with Target CellsEffects Caused by HormonesControl Mechanisms of Endocrine GlandsLocation of Major Endrocrine OrgansPituitary GlandHormones of the Anterior PituitarySlide 11Hormones of the Posterior PituitaryThyroid GlandThyroid HormoneCalcitonin (Calcium deposition)Parathyroid Glands (Calcium removal)Adrenal GlandsAdrenal Hormones and Their LocationsAdrenal Cortex (Outer Portion)Hormones of the Innermost Cortex LayerHormones of the Adrenal MedullaPancreatic IsletsSlide 23Pancreatic Hormones and Blood SugarPineal GlandHormones of the OvariesSlide 27Hormones of the TestesOther Hormone-Producing Tissues and OrgansDevelopmental Aspects of the Endocrine SystemEndocrine System Role of the Endocrine SystemHormones: TypesTransport of HormonesInteraction of Hormones with Target CellsEffects of Hormones on TargetControl Mechanisms of Endocrine GlandsEndocrine Organs•Pituitary (Anterior and Posterior)•Thyroid•Parathyroids•Adrenals (Cortex, Medulla)•Pancreas•GonadsOvariesTestesThe Endocrine SystemA more broad-based and long-lasting communication system than the nervous systemUses chemical messages (hormones) that are released into the bloodHormones control several major processes•Reproduction•Growth and development•Mobilization of body defenses•Maintenance of much of homeostasis•Regulation of metabolismTypes of HormonesProtein-based hormonesSteroid hormonesProstaglandins and catecholaminesInsulin Growth hormoneHormones as Chemical MessengersEndocrine gland (source)Target organs or glandsHormones move through the bloodstream to target organsHormone Interaction with Target CellsHormones bind to receptors sticking out from the plasma membrane of target cells or within target cells growth factor insulin epinephrine HormonesExamples of receptors found in the plasma membrane of cellsReceptorsEffects Caused by HormonesChanges in electrical state of the cell, stimulating changeCauses enzymes to be made, changing metabolic abilities of target cellTurn on or off enzymes that alter metabolism inside cellStimulate cell division and multiplicationTurn on certain genesControl Mechanisms of Endocrine GlandsHormonal: Chemical stimulus (i.e. endocrine glands are activated by other hormones)Humoral/Blood-Based: Changing blood levels of certain ions stimulate hormone releaseNeural: Nerve impulses stimulate hormone release; most are under control of the sympathetic nervous systemLocation of Major Endrocrine OrgansFigure 9.3Pituitary Glandglandular tissue nervous tissueblood portal systemNervous system that hormones can drip down onFlip and enlargeHormones of the Anterior PituitarySix anterior pituitary hormones•Two affect non-endocrine targets•Four stimulate other endocrine glands (tropic hormones)Characteristics of all anterior pituitary hormones•They are proteins (or peptides)•They act through second-messenger systems•They are regulated by hormonal stimuli, mostly negative feedbackHormones of the Anterior PituitaryIncreases bone and skeletal massCauses milk secretion in breastsCauses follicle and sperm maturation, ovulation and testosterone productionStimulates thyroid hormone secretionCauses aldosterone, glucocorticoid, or androgen releaseHormones of the Posterior PituitaryInhibits diuresis (urine production) and increases blood pressureStimulates uterine muscle contraction in labor and intercourse; causes milk ejectionThyroid GlandFigure 9.6Thyroid hormoneControls rate of cellular respiration. All body cells are targets.CalcitoninDecreases blood calcium levels by causing bone calcium deposition. Made by parafollicular cells.Consists of two lobes and a connecting isthmusThyroid HormoneLack of Dietary Iodine: GoiterHyposecretion of thyroxine( hypothyroidism in adults)Hyperthyroidism (Grave's disease)Calcitonin (Calcium deposition)Decreases blood calcium levels by causing its deposition on boneAntagonistic to parathyroid hormoneProduced by C (parafollicular) cellsFigure 9.9Parathyroid Glands (Calcium removal)Parathyroid hormone1. Stimulates osteoclasts to remove calcium from bone2. Stimulates the kidneys and intestine to absorb more calcium3. Raises calcium levels in the bloodFound on posterior surface of thyroidAdrenal GlandsTwo parts that act as if separate glands•Cortex – outer glandular region in three layers•Medulla – inner neural tissue regionSits on top of the kidneysAd-renal both mean “upon orEpi-nephros next to the kidney”&Adrenal Hormones and Their LocationsAdrenal CortexOuter portion produces mineralocorticoids like aldosteroneMiddle layer produces glucocorticoids like cortisone and cortisolInnermost layer produces androgens like estrogens and testosteroneMedulla produces catecholoamines like epinephrine and norepineprhineAdrenal Cortex (Outer Portion)Aldosterone release causes salt and water retention, increasing blood pressureHormones of the Innermost Cortex LayerSex hormones (steroids)•Produced in the inner layer of the adrenal cortex•Androgens (male) and some estrogen (female) -- both produced regardless of gender•Hypersecretion causes masculinization (regardless of gender) - most obvious effects in females•Hyposecretion causes Addison's diseaseHormones of the Adrenal MedullaProduces two similar hormones (catecholamines)•Epinephrine•NorepinephrineThese hormones prepare the body to deal with short-term stressSympathetic system stimulates catecholamine release in fight or flight: increased heart rate, blood pressure, blood gluocose, respiratory ratePancreatic IsletsThe pancreas is a mixed glandThe islets of the pancreas produce hormones•These hormones are antagonists that maintain blood sugar homeostasisPancreatic IsletsFigure 9.13Insulin Allows glucose to cross plasma membranes into cells from beta cells (hypoglycemic hormone)Glucagon Allows glucose to enter the blood from alpha cells (hyperglycemic hormone)Pancreatic Hormones and Blood SugarFigure 9.14Pineal GlandFound on the third ventricle of the brainSecretes melatonin•Helps establish the body’s wake and sleep cycles•May have other as-yet-unsubstantiated functionsHormones of the OvariesEstrogens•Produced by Graafian follicles or the