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44 Cards in this Set
- Front
- Back
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2 Systems That Control Entire Body
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Nervous and Endocrine Systems
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Differences Between Nervous and Endocrine Systems
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Chemicals used: - neuroxmitters v. hormones - neurohormone: neuron into blood stream Response: - fast, short lasting v. slow, long lasting Synthesis: - most of glands v. adrenal cortex, gonads and placenta |
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Hormones
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Cell to cell communication molecules
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Characteristics of a Hormone
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Made in glands or cells Transported by blood Bind to distant target tissue receptors Activate physiological response Exert effects despite low concentrations Length of activity determined by half life - lipid (long) v. water soluble (short) |
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Hormone Function
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Control rate of enzymatic rxns Transport of ions or molecules across cell membrane (control of carriers/channels) Gene expression and protein synthesis |
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Hormone Classification
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1) Peptide or protein hormones 2) Steroid hormones 3) Amine hormones |
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Effect of Water Solubility on Hormone
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- stored in vesicles - released via exocytosis - short half life - dissolves in plasma - receptors on cell membrane, activates 2nd messenger |
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Effect of Lipid Solubility on Hormone
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- synthesized on demand - released via diffusion - long half life - binds to carrier in plasma - receptor on cell memb, in cytosplasm/nucleus, activates genes for transcription/translation |
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Peptide Hormones |
Derived from proteins (H2O soluble) Made in advance, stored in secretory vesicles Exocytosis release Transported by dissolving in plasma Short half life Receptors on cell membrane Response by activation of 2nd messenger Mods existing proteins |
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Peptide Hormone Synthesis
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Preprohormone: large, inactive chain from ribosomes enters Rough ER Prohormone: signal seq removed, smaller, inactive Packaged w/ proteolytic enzymes by Golgi Post-translational mod: prohormone chopped into active hormone Exocytosis Signal transduction system: initiates cellular response |
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Peptide Hormone Receptor Complex
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Cell Membrane receptors 1) G coupled protein - activates channels - 2nd messenger - direct effect 2) Enzyme receptor - Tyrosine Kinase |
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Steroid Hormones
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Derived from cholesterol (lipid soluble) Synthesized on demand Simple diffusion release Transported bound to carrier protein in plasma Long half life Receptors on membrane, in cytoplasm/nucleus Response by activation of gene for transcription and translation Induction of new protein synth. |
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Steroid Hormone Action
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Initially bound to plasma protein carrier, released when needed. Bind to receptors (memb, cytoplasm or nucleus) Receptor complex binds to DNA - activate/repress genes Activated genes gen mRNA (transcription) New protein produced (translation) |
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Amine Hormones
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Derived from 2 AAs 1) Tryptophan: melatonin 2) Tyrosine: Catecholamines and Thyroid Hormones |
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Tyrosine Derived Amine Hormones
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Catecholamines: H20 soluble Thyroid Hormones: lipid soluble |
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Tyrosine Derived Catecholamines
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H20 soluble Made in advance and stored in secretory vesicles Exocytosis Transported dissolved in plasma Short half life Receptors on cell membrane Response by activation of 2nd messenger Modifies existing proteins |
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Tyrosine Derived Thyroid Hormone
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Lipid soluble Made in advance and stored bound to thyroglobulin Simple diffusion out Transported in plasma bound to carrier protein Long half life Receptors in nucleus Response is activation of genes transcript/ translation New protein synth. |
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Glands of The Body
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Pineal Gland Hypothalamus (N) Posterior Pituitary (N) Anterior Pituitary Thyroid Gland Parathyroid Gland Thymus Gland Heart Liver |
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Pineal Gland
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Secretes melatonin - amine, AA derivative (tryptophan) - sleep/wake cycle |
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Hypothalamus
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Secretes trophic hormones - peptide Target: anterior pituitary Effect: release/inhibit pituitary hormones |
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Posterior Pituitary
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Nervous tissue Secretes: oxytocin and vasopressin (peptide) Targets: Breast and Uterus & Kidney Effect: lactation and labor, water reabsorption |
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Anterior Pituitary
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Secretes - prolactin - growth hormone (somatotrophin) - corticotropin (ACTH) - thryotropin (TSH) - follicle stimulating hormone - luteinizing hormone (all peptides) |
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Prolactin
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Secreted by anterior pituitary Peptide hormone Target: breast Effect: lactation |
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Growth Hormone (Somatotrophin)
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Secreted by anterior pituitary Peptide hormone Target: liver and other tissues Effect: growth factor secretion, growth and metabolism |
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Adrenocorticotropin Hormone (ACTH)
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Secreted by anterior pituitary Peptide hormone Target: adrenal cortex Effect: cortisol release |
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Thyrotropin (TSH)
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Secreted by anterior pituitary Peptide hormone Target: thyroid gland Effect: thyroid hormone synthesis |
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Follicle Stimulating Hormone (FSH)
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Secreted by anterior pituitary Peptide hormone Target: Gonads Effect: egg or sperm production, sex hormone production |
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Luteinizing Hormone
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Secreted by anterior pituitary Peptide hormone Target: gonads Effect: sex hormone production, egg or sperm production |
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Thyroid Gland
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Secretes: Triiodothyronine/Thyroxine (peptide) - target: many tissues - effect: metabolism, growth, and devolopment Calcitonin (amine) - target: bones - effect: plasma Ca levels |
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Parathyroid
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Secretes: Parathyroid Hormone (peptide) Target: bone and kidney Effect: regulates plasma Ca and PO4 levels |
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Thymus Gland
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Secretes: Thymosin and thymopoietin (peptide) Target: lymphocytes Effect: lymphocyte development |
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Heart
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Secretes: Atrial natriuretic peptide Target: kidneys Effect: increases Na excretion |
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Liver
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Secretes: angiotensinogen - target: adrenal cortex, bld vessels - effect: aldosterone secretion, increased BP insulin like growth factor - target: many tiss - effect: growth |
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Endocrine Reflex Pathway
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Stimulus Afferent Signal Integration Efferent Signal (release of hormone) Physiological action (@ target) Negative feedback |
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2 Types of Endocrine Pathways
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1) Simple - endocrine cell works as integrating center - does not involve CNS - i.e. low plasma [Ca2+] 2) Complex - CNS involved - most common |
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Neurohormones
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Hormones secreted by neurons into bld stream Adrenal medulla: epinephrine Hypothalamus: - Posterior Pituitary - Vasopressin: increase H2O reabsorption - Oxytocin: contractions, breast feeding |
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Pituitary Gland
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2 fused glands anterior: true endocrine gland - secretes 6 hormones posterior: extension of neural tiss - stores and releases 2 neurohormones (vasopressing and oxytocin) |
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Trophic Homones
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Hormones that control the secretion of other hormones
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3 Levels of Endocrine Control
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Hypothalamic stimulation from CNS Pituitary stimulation - due to hypothalamic trophic hormones Endocrine gland stimulation - due to pituitary trophic hormones |
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Hypothalamus Hypophyseal Portal System
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Hypothalamus neurohormones transported to anterior pituitary, acting directly on endocrine cells. Endocrine cells release hormones into 2nd capillaries |
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6 Anterior Pituitary Hormones
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1) Prolactin (non trophic) 2) Thyroid stimulating hormone (thyroid) 3) Adrenalcorticotrophic hormone (adrenal cortex) 4) Growth hormone (liver) 5) Follicle stimulating hormone (gonads) 6) Luteinizing hormone (gonads) |
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Hypothalamic Pituitary Feedback Loops
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Long-Loop (-) Feedback - hormone secreted by peripheral endocrine gland feeds back to pituitary/hypothalamus Short-Loop (-) Feedback - pituitary hormone feedsback to hypothalamus |
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Hormone Interactions
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1) Synergism: multiple stimuli (glucose, E, cortisol) 2) Permissiveness: 2nd hormone necessary for full expression (renin&ANGII, GH&IGF) 3) Antagonism: opposing effect (glucagon/insulin & parathyroid&calcitonin) |
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Endocrine Pathologies
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Glandular Level: - Hypersecretion: excess hormone release - Hyposecretion: deficient hormone release Receptor Level: - Down regulation: decrease # - transduction abnormalities: - pathway abnormalities |
