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Unformatted text preview: TA: Ishita Desai OH: Th 10-11, Café Roma Section: Th 9-9:50am, Center 217B [email protected] Handout #3 – TA Version POSTERIOR PITUITARY List two hypothalamic hormones that do not enter the hypothalamic-pituitary portal system. Include the stimuli for their secretion, their target organ(s), and their action(s). Hormone 1: Oxytocin, stimulated by nipple stimulation or stretch of the cervix, causes contraction of uterus and breast duct cells: milk letdown Hormone 2: ADH or vasopressin, stimulated by increased plasma osmolarity or decreased blood pressure or volume, causes arteriolar vasoconstriction and insertion of aquaporins in the collecting duct of the kidney increasing water reabsorption and blood pressure Jenny is suffering from the following symptoms: increased BP, swelling of the feet, fatigue and confusion. Blood tests show much lower than normal Na+ levels. What could Jenny be diagnosed with? ADH over-expression, which can cause increased H2O reabsorption concentrated urine and increased blood volume increased BP; increased blood volume edema (swelling); increased H2O reabsorption decreased ion concentration decreased Na+ hyponatremia fatigue and confusion Oxytocin • Utilizes the Gq receptor (GPCR) to increase contraction via the increased release of Ca+ + (bu increase PKC). • Sensitivity to oxytocin is increased during pregnancy by: o Increased estrogen increased oxytocin receptors o The activity of the receptor itself (during pregnancy) is inhibited by: Increased progesterone inhibits activity of oxytocin receptors Diagram the release of oxytocin during labor and the milk ejection/let down reflex. Head of fetus stretches cervix (mechanoreceptors) --> sensory nerves --> sensory neurons --> spinal chord --> increased oxytocin release from hypothalamus--> increased uterine contraction s--> push head forward --> more oxytocin release, etc Suckling -> hypothalamus -> ↑ oxytocin -> contraction -> milk ejection THYROID HORMONES Hypothalamus TRH ant pit (thyrotrophs) TSH thyroid follicular cells...
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This note was uploaded on 04/06/2012 for the course BICD 150 taught by Professor Fortes during the Winter '09 term at UCSD.
- Winter '09