Lecture 25 - Dhillon

By working on the cell membrane melatonin im not going

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Unformatted text preview: transcription -They can also behave like peptides! (by working on the cell membrane) Melatonin "I'm not going to ask you about Melatonin" • • • Darkness hormone Secreted at night (Sleep) Made in pineal gland (also gi tract, leukocytes, other brain regions) Diverse effects: Transmits information (light-dark cycles to govern the biological clock) Immune modulation Anti-oxidant Lesion of the pineal gland = mice can't sleep "Not going to ask you about this" Tyrosine-derivatives -All structures are pretty similar, but changing the s tructure just by a little bit will change the way it c an bind to what receptors greatly "You can just cross this out of your slides" Synthesis of catecholamines Synthesized in adrenal medulla (mainly in cytosol) Stored in vesicles prior to release Figure from: http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/adrenal/medhormones.html -The endocrine itself can act as a regulator of it's own function PANCREATIC CELL is a good example! Endocrine cells directly sense stimuli, then secrete the hormone (integrating centre) Stimuli Endocrine cell Hormone release H H Metabolite AA's, Fatty Acids Hormone Insulin, Glucagon, Somatostatin Neurohormone Neurotransmitter example Glucose H H H H pancreatic b cell -All of these stimuli change the e lectrical potential/ threshold of the c ell -Changes the potential of the cell that i ncreases or decreases the likelihood of a h ormone being released Insulin Insulin H H **"KNOW THIS PATHWAY, BECAUSE I MAY ASK YOU GUYS THIS. STAR THE PAGE" Example: glucose stimulation of insulin release -Beta cells can sense how much glucose is in our blood -It tells the Beta cell how much i nsulin needs to be produced in response to the [glucose] http://ciitn.missouri.edu/cgi-bin/pub_view_project_ind.cgi?g_num=11&c_id=2007009 PATHWAY: Glucose enters the cell --> Increases the ATP/ADP Ratio --> ATP bids to the ATP-Gated K+ Channel --> Prevents K+ f rom leaving the cell --> Threshold required to depolarize the cell decreases --> Depolarization occurs --> Voltage-Gated Ca+ C hannels open --> Ca++ influx occurs --> CACIUM-DEPENDENT EXOCYTOSIS: Insulin vesicles are released into the blood --> G lucose uptake is increased Hormones released from the hypothalamus and anterior pituitary regulate the release of several hormones -Hypothalamus is connected to the Pituitary via a PORTAL SYSTEM -Hypothalamaic-hypophesial Portal System: Hypothalamic cells --> Project to the Portal System --> Release Tropic Hormone --> Stimulate Anterior P ituitary Glands to release THEIR hormone -Anterior pituitary is not part of our brain: -It is an ENDOCRINE GLAND that is formed from the roof of our mouth and migrates upwards --> Meets up with the POSTERIOR PITUTIATRY (part of our brain b/c it is made up of neurons) Anterior pituitary Hypothalamic releasing and inhibitin...
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