20000187
Description
Flashcards by Marissa Alvarez, updated more than 1 year ago
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Created by Marissa Alvarez
about 5 years ago
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| Question | Answer |
| Objectives: | •Review the types of intercellular communication •Learn the difference between endocrine vs. nervous signal transduction •Identify the surface membrane receptor types categorized by mode of action •Examine the classification of hormones •Identify the differences b/w the synthesis, storage, & secretion of peptide & steroid hormones •Compare the mechanisms of action of peptide & steroid hormones •Examine the overall functions & complexity of the endocrine system •Examine the various influencing parameters on hormone plasma concentrations such as: secretion rate, metabolic conversion &/or inactivation, binding to transport proteins, negative-feedback, neuroendocrine reflexes, circadian rhythms, hypo- and hypersecretion, receptor populations, permissiveness, synergism, & antagonism. |
| Definition of Endocrinology: Study of _____ chemical adjustments and other activities accomplished by hormones Endocrine glands are scattered throughout the body and secrete _____ Endocrine glands and their targets are not connected _____, but are connected by the hormones that they secrete Endocrine glands function in an endocrine sense, but can have other functions as well ______ function involves the secretion of chemicals into ducts or passageways connected to the ____ environment (body surface, digestion) | homeostatic hormones anatomically Exocrine, external |
| Endocrine System Basic Schematic | |
| Endocrine System –____ glands –____ target cells •Dependent on ____ (H -> H+R -> final effect) •Overall functions: –Regulate organic metabolism –Regulate H20 and electrolyte balance –Induce ∆s to help body cope with stresses –Promote growth and development –Control reproduction –Regulate RBC production –CV and GI control/integration * “__ and __” Concept | Ductless SPECIFIC receptor Lock and key |
| Nervous System VS. Endocrine System Nervous system is "___" system -___ arrangement b/w neurons & target cells -___ released into synaptic cleft -Very __ distance (diffuses across synaptic cleft) -dependent on ___ anatomical relationship b/w neurons & their target cells -Generally ___ response -___ duration of action -Coordinates ___ , ___ resposnes Endocrine system is a "___" system -endocrine glands __ structurally related to one another OR target cells -_____ released into the blood -____ distance (carried by blood) -dependent on ___ of target cell binding & responsiveness to a particular hormone -Generally ____ repsonse -___ duration of action -Controls acititvities that require ____ ___ rather than speed | Nervous System: wired structural NT's SHORT CLOSE rapid brief rapid, precise Endocrine system: wirless NOT Hormones LONG specificity SLOW Long LONG duration |
| INdirect Intracellular Communication Paracrine: ___ acting Ex. Histamine (blood vessel dilation) Hormones: ___-range Ex. Ant. Pituitary hormones Neurotransmitters: Very ____-range Ex. NE on pancreas β-cells Neurohormones: (____) Ex. Gonadotropin Releasing-Hormone *happens a lot with brain & pituitary | Locally Long short neuroendocrine |
| Intracellular Communication ___ ____ – process by which incoming signals are conveyed to the target cell, where they are transformed into the dictated cellular response. Occurs by different mechanisms depending on chemical messenger and receptor type Mechanisms: 1)Opening or closing ___ gated receptor-channels 2)Activating receptor-enzymes (receptor functions as an ___) 3) Activating second messenger pathways via ____ receptors 4) Binding to receptors to ___ change gene activity | Signal Transduction chemically enzyme G-protein coupled internally |
| Intracellular Communication - Signal Transduction 1) Opening or closing chemically gated receptor-channels Receptor serves as ___ -Can open or close (___ or ___) General STEPS: extracellular messenger binds -> binding leads to opening of receptor -> ions enter -> ions lead to cellular response | channel EPSP’s or IPSP’s |
| Intracellular Communication - Signal Transduction 2) Activating receptor-enzymes (receptor functions as an ___) *Protein ___ – any enzyme that transfers a phosphate (PO4) group from ATP to an intracellular protein Protein kinases are altered in two ways: 1 – ___ kinase 2 – ____ Receptors | enzyme kinase tyrosine G-Protein Coupled |
| Intracellular Communication - Signal Transduction 2) Activating receptor-enzymes General STEPS for Tyrosine kinase pathway: extracellular messenger binds to receptor -> binding activates protein kinase -> protein kinase activates specific protein -> active protein leads to cellular response *Receptor itself acts as an ____ | enzyme |
| Intracellular Communication - Signal Transduction 3) Activating second messenger pathways via ____ receptors General STEPS for GPCR pathway: extracellular (1st) messenger binds to receptor -> Receptor activated G protein -> G protein alpha subunit activates effector protein -> effector protein makes 2nd messenger -> 2nd messenger activates protein kinase -> Protein kinase activates specific protein -> Active protein leads to cellular response Turned off by _____, which are usually continuously active ->Extracellular messenger is released to be degraded or excreted or the ligand-receptor complex can be internalized and degraded. *EX: ____ hormones | phosphatases hydrophilic |
| REVIEW Endocrine vs. neural communication: ->non-connected vs. structurally connected ->long vs. short distance of acton ->brief action vs. long-lasting action ->neurotransmitters vs. hormones ->precision vs. duration Indirect types of cellular communication: ->paracrine hormones ->neurotransmitters ->neurohormones Types of receptors: ->Chemically gated receptor channels ->Activating receptor enzymes ->Activating second messenger pathways (hydrophilic) ->Internal receptors that change gene activity (lipophilic) | |
| Hormone classifications 1) Hydrophilic: -> ___ water solubility ->___ fat solubility a) Peptides •___ chains of amino acids –Ex. Oxytocin •Can be long -> Protein range –Ex. Growth hormone b) Glycoproteins –_____ conjugated to protein •Ex. Follicle Stimulating Hormone (FSH), Luteinizing Hormone(LH) | high low Short Carbohydrates |
| Hydrophilic PEPTIDE hormone synthesis: Same steps as for any protein: 1. Preprohormone in rough ER 2. Migrate to golgi in transport vesicles during which they are cleaved to the mature hormone sequence. 3. Golgi complex packages them into secretory vesicles Hydrophilic peptide hormone secretion and transport: –>Storage •In ___ ->Secretion •Occurs upon specific stimuli •____ release –Transport •Dissolved in ____ | cytoplasm Regulated blood |
| OTHER Hydrophilic Hormones Amines -Amino-acid derivatives Catecholamines: made from ____ ->Secreted from the __ ___ Indoleamines: made from ____ ->Secreted from the ___ ___ **Storage and secretion the same as peptides. BUT 50% of catecholamines are bound to ____ for transport | tyrosine adrenal medulla tryptophan pineal gland albumin |
| Hydrophilic Hormone Mechanisms of Action Cyclic AMP Pathway Adenyl cyclase = ____ protein Adenyl cyclase -> cAMP (__ ____) -> protein kinase A -> activates protein & gets cellular response | effector 2nd messenger |
| Hydrophilic Hormone Mechanisms of Action IP3-Ca2+ Pathway _____ = effector protein Phospholipase C -> IP3 -> Ca2+ (__ ___) -> calmodulin -> cellular response Also get: Phospholipase C -> DAG (2nd messenger) *NOT ___ soluble -> activates protein -> cellular response | Phospholipase C 2nd messenger not water soluble (so stays near inner plasma membrane) |
| Hydrophilic Hormone Mechanisms of Action Minute quantity for overall effect –Multiple steps This know as _____? | AMPLIFICATION !!! You can get a ton of different responses to SAME signal (signal amplification) from a single hormone binding. |
| Hormone classifications Continued ... Lipophilic (__ loving) - ___ Soluble (do NOT like aqueous environ. but DO like ___ ___ and nucleus) 1. Steroids ->Cholesterol derivatives (Ex. Estrogen, testosterone, cortisol, aldosterone) 2. ____ Hormone Made from Tyrosine (like ____) ->But has 2 tyrosine amino acids ->T4 = has 4 iodines ->T3 = has 3 iodines | lipid FAT plasma membrane Thyroid catecholamines |
| Lipophilic Steroid Hormone Synthesis Synthesis begins with common precursor followed by a series of enzymatic steps Some ____ may occur once secreted into blood or upon arrival at target organs (Ex: Testosterone to Estradiol) (EX: Also true for Thyroid Hormone T4 -> T3) ***THE TYPE(S) OF STEROID HORMONE(S) THAT A TISSUE MAKES DEPENDS UPON ITS COMPLEMENT OF ____!*** | modification ENZYMES |
| Lipophilic Hormone Storage, Secretion, & Transport –Storage •__ stored –If formed, immediate diffusion –Secretion •Dependent on ___ of synthesis –Reminder: Some ___ may also occur in blood/tissues [Ex: T -> E2 (also T4 to T3)] –Transport •____ bound to plasma proteins (Specific binding protein OR ___) •Only ____ hormones (small fraction of total) free to bind to receptors *Catecholamines – 50% bound, 50% free | NOT rate modification Reversibly Albumin unbound |
| Lipophilic Hormone Mechanisms of Action •Most act through ___ activation –Specific hormones have specific hormone response ___ (EX: the estrogen-estrogen receptor complex binds to the estrogen response element) Some (i.e. __ steroids) can bind to membrane-bound receptors to evoke __-gene-activating activities | gene elements sex non |
| Determinants of Plasma Hormone Concentration 1) Metabolism •Activation/conversion (Ex: Thyroid Hormone) –T3 __ ___ than T4 2) Plasma protein binding (Ex. Lipophilic hormones) –___ H is monitored 3) Metabolic inactivation •Liver, kidney, blood, target cells __ hormone 4) ___ rate •↑ release -> ↑ [H] | more potent Unbound clear 4) Secretion rate |
| REVIEW: Hydrophilic vs. lipophilic hormones ->protein synthesis machinery vs. enzymatic (modification of cholesterol) ->Secretory granules and stimulus vs. release upon synthesis ->Freely moves in blood vs. specific transport proteins ->Cell membrane receptors vs. nuclear actions via a HRE Determinants of Plasma Hormone concentrations: ->Secretion rate ->Metabolism ->Plasma binding proteins ->Metabolic inactivation |
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