Endocrine System IIFirst, Let’s Compare Some General Aspects of the Nervous and Endocrine SystemsNervous vs. Endocrine SystemsSlide 4What is an Endocrine Axis?The HPA AxisGeneral Properties Of HormonesYou Only Need A Small AmountEnzyme AmplificationHormones are Cleared By The LiverTarget Cells Modulation of SensitivityModulation of Target Cell SensitivityHormones So Similar In Structure…..Paradoxical EffectsHormone TransportMechanism of Hormone ActionSome Differences Between ClassesSteroid Hormone ActionNonsteroid Hormone ActionModulation of Target CellsHormone InteractionsWhat Do We Mean BY a Second Messenger? What is the First Messenger?Hydrophilic Hormones: Mode of Action cAMP as Second MessengerHydrophilic Hormones: Mode of Action Other 2nd and 3rd MessengersII. Overview of the Endocrine SystemLocation of Major Endrocrine OrgansDo Other Tissues, Besides the Endocrine glands, Secrete Hormones?Other Organs Not Considered Endocrine Organs, That Secrete Hormones:What Are the Hormones For Each Gland? What do they DO?Slide 30Going Back a Chapter….. 1. Neural Stimuli of Endocrine Glands2. Control of Hormone Release by Negative Feed back (Rarely Pos.Feedback)3. Hormonal Stimuli of Endocrine Glands ( Tropic Stimuli)4. Humoral Stimuli of Endocrine Glands (See Below)Let’s Look at The Glands,Their Function and ControlThe HypothalamusParathyroidsThyroid Gland(3 Hormones:T3,T4 ,Calcitonin)Slide 39If you have a Thyroid Hormone DeficiencyGrave’s DiseaseLast time We Define A Second Messenger System:Slide 43Adrenal Gland: CortexMineral CorticoidsSlide 46GlucocorticoidsGlucocorticoids ( Zona fasiculata)ADDISON’S DISEASECushing’s DiseaseSlide 51Adrenal MedullaSlide 53Gonadocorticords: Zona ReticularisPancreasGlucose: A Simple SugarPolysaccharides =CarbohydratesDuring Low Blood SugarDuring High Blood Sugar (after a meal)Slide 60What is Diabetes Type IDiabetes Type IIDiabetes Mellitus (if Not controlled Properly)What is Insulin Resistance?Diabetes InsipidusOvariesSlide 67Slide 68Slide 69Slide 70TestesLEPTINAdipocytes and LeptinSlide 74Ghrelin: Beware of what lines your Tummy!ThymusPineal GlandSlide 78Endocrine System IIFirst, Let’s Compare Some General Aspects of the Nervous and Endocrine SystemsNervous vs. Endocrine SystemsCommunicationnervous - both electrical and chemicalendocrine - only chemicalSpeed and persistence of responsenervous - reacts quickly (1 - 10 msec), stops quicklyendocrine - reacts slowly (hormone release in seconds or days), effect may continue for weeksAdaptation to long-term stimulinervous - response declines (adapts quickly)endocrine - response persists Area of effectnervous - targeted and specific (one organ)endocrine - general, widespread effects (many organs)What is an Endocrine Axis? This is a Relationship between the hypothalamus, pituitary and a more remote gland…………. There are Three:1. Hypothalamic-Pituitary-Gonadal Axis2. Hypothalamic-Pituitary-Thyroid Axis3. Hypothalamic-Pituitary-Adrenal AxisThe HPA AxisREMEMBER the Dry Lab data analysis using stressed mice. There was a control group of mice with a complete HPA.Subsequent groups had variations with missing pieces of this axis.The HPG and HPT axis each work in a similar mannerGeneral Properties Of HormonesYou Only Need A Small AmountA Small Amount of Hormone Goes A long Way: ---One molecule activates thousands of enzymes molecules through a process called enzyme amplificationEnzyme AmplificationHormones are Cleared By The LiverAND…. Different hormones vary in their rates of clearance.The rate of hormone removal is called the metabolic removal clearance rate (MCR).The length of time required to clear 50% of the hormone is from the blood is the half-life.Each hormone have a specific Half-life which differs due to different molecule structure, weight , whether it is bound or unbound to a transport protein.Target Cells Modulation of SensitivityTarget cells can modulate (adjust) their sensitivity to a hormone.Upregulation- A Cell increases the number of hormone receptors and becomes MORE SENSITIVE to a hormone.Downregulation- A cell reduces its receptor number and become less receptive to hormone.Modulation of Target Cell SensitivityLong-term use of high pharmacological dosesbind to receptor sites of related hormonestarget cell may convert to different hormoneHormones So Similar In Structure…..Paradoxical EffectsA target cell can convert one hormone such as testosterone to estrogen, during its pharmacological use. This may have paradoxically, feminization effects!Hormone TransportMonoamines and peptides are hydrophilic mix easily with blood plasma Steroids and thyroid hormone are hydrophobic must bind to transport proteins for transportbound hormone - attached to transport protein, prolongs half-life to weeksprotects from enzymes and kidney filtrationunbound hormone leaves capillary to reach target cell (half-life a few minutes)Transport proteins in blood plasmaalbumin, thyretin and TGB (thyroxine binding globulin) bind to thyroid hormonesteroid hormones bind to globulins (transcortin)aldosterone - no transport protein, 20 min. half-lifeMechanism of Hormone Action1. Overall: HORMONES influence TARGET CELLS.2. They are “ligands” to receptors on cell membranes.3. Once bound, hormones alter cell activity by 1. altering plasma membrane potential ( opening ion channels) 2. stimulates synthesis of proteins ..usually regulatory such as enzymes or 3. either activates or deactivates enzymes. 4. Stimulates mitosis.Some Differences Between ClassesSteroids Hormones- Transported by carriers, as they are hydrophobic, are known to bind to the chromatin (DNA) and initiates transcription.Protein/Peptide Hormones- Cannot penetrate cell membrane- These use 2nd messenger systems. AND they usually Activate/deactivate enzyme system that are there rather than create more.Steroid Hormone ActionSTEROID HORMONE ANIMATIONFigure 9.1aPRESS TO PLAYNonsteroid Hormone ActionNONSTEROID HORMONE ANIMATIONFigure 9.1bPRESS TO PLAYModulation of Target CellsHormone InteractionsMost cells sensitive to more than one hormone and exhibit interactive effectsSynergistic effectsPermissive effectsone hormone enhances response to a second hormoneAntagonistic effectsWhat Do We Mean BY a Second Messenger? What is the First Messenger?Hormones the activate 2nd messengers work through