PHIS 206 1st EditionLecture 35Outline of Last Lecture I. DiagramII. Metabolism in the BrainIII. Hormones that are Major Players in Determining which StateIV. InsulinV. Diabetes MellitusVI. Glucagon VII. Fed v. Fasting StateOutline of Current Lecture I. We Regulate 3 Hormones for PlasmaII. Plasma Calcium LevelsIII. Parathyroid HormoneIV. BonesV. Parathyroid Hormone in KidneysVI. Parathyroid Hormone in IntestinesVII. Control of ParathyroidVIII. CalcitoninIX. Vitamin DX. Normal Plasma Calcium LevelsXI. Deficiency in Vitamin D, Calcium, Parathyroid HormoneXII. Parathyroid Hormone DisordersXIII. Vitamin D Deficiency XIV. Fracture BonesCurrent LectureI. We Regulate 3 Hormones for Plasma-Parathyroid Hormone-Calcitonin: peptide-Vitamin D: steroid-99% of Ca in body is in the bones + teeth-0.9%: in soft tissues-0.1%: in plasma 0.05% = free in plasma ONLY PART WE REGULATE 0.05% = bound in plasmaII. Plasma Calcium Levels These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Renal ExcretionIntestinal AbsorptionPlasma Ca2+ LevelsIII. Parathyroid Hormone-primary regulator-peptide-effects on bone, renal excretion indirectly: absorption of calcium of renal through lumen-overall effect: increase plasma calcium levelsIV. Bones-like a lock-tissue that is metabolically inert: you might think-BUT bone IS metabolically active-matrix: consists of collagen (fibrous protein that makes up cartilage)-calcium phosphate: makes bones hard and brittle-bones (mechanical): collagen with calcium phosphate deposited on it called matrix-matrix is constantly being dissolved and reformed constantly losing calcium in plasma constantly digesting collagen-dissolution of bone is random-but deposition occurs along the lines of stress + compression thickest and most rapid forming along these lines called bone remodeling-parathyroid causes increase in removal of calcium and phosphate into plasma promotes bone dissolution-chronic deficiency results in loss of bone densityV. Parathyroid Hormone in Kidneys-mobilizing calcium and phosphate, so increasing levels-increase calcium and prevent phosphate from precipitating -when you add calcium, you add phosphate-increases reabsorption of calcium from nephron to plasma-increases rate of excreting phosphate so major effect: increase calcium and decrease phosphate-end result: decrease calcium phosphate in bones and teeth; increase calcium phosphate in plasma; does not affect plasma phosphate levels muchVI. Parathyroid Hormone in Intestines-not direct effectBones and TeethBones and Teeth-absolute dependent on Vitamin D Activated Vitamin Do 2 transformations in liver and kidneyo required to absorb calcium into lumeno parathyroid hormone promotes activation of Vitamin D in the kidneyVII. Control of Parathyroid-no endocrine + neural control -secretion is direct response to plasma calcium levels VIII. Calcitonin-secreted by thyroid gland; cells that secrete is called C-cells -decreases plasma calcium levels -secretion by simple (-) feedback -physiologically, a calcitonin is not important unless lactationIX. Vitamin D-doesn’t do anything by itself (no absorption)-need metabolic production: Activated Vitamin D no Activated Vitamin D, no Calcium Deficiency-Vitamin D is a precursor to Activated Vitamin D-Vitamin D deficiency: hypercalcemic -2 Sources of Vitamin D synthesized in skin exposed to sunlight is not an adequate source of Vitamin D another source is in dieto most common source of Vitamin DX. Normal Plasma Calcium Levels-vary secretion of Parathyroid Hormone-increase Parathyroid to promote phosphate excretion and calcium absorption in lumen-promotes Vitamin D activation to increase calcium absorption in the gut XI. Deficiency in Vitamin D, Calcium, Parathyroid Hormone-bones lose density and become weak + fragile-use last bit to maintain normal plasma calcium levelsXII. Parathyroid Hormone Disorders-hyperparathyroidism: elevated plasma calcium levels, reduced bone density muscle weakness depress neural activity poor memory kidney stones bone density decreases; bones weaken -hypoparathyroidism: muscle excitability; spasms-complete lack: fatal; calcium so low that respiratory system goes into spasmic contractionsXIII. Vitamin D Deficiency -reduced ability to absorb Vitamin D-reduced bone density: adults-bones less rigid (condition called Rickett’s): in children flexible bones-osteoporosis: rate of reduction at which new bone gets laid down; around age 50+ causes reduction in bone mass more common in women hunched back b/c neck loses rigidity plasma calcium levels are normal younger women: estrogen prevents it exercise builds bones and makes it less likely to get osteoporosisXIV. Fracture Bones-broken end decalcifies-bone becomes flexible and sticky -align it back but not touching (just close enough to get the blood circulating)-over time, soft gummy stuff calcifies, so product is bone with a bump-bone will be considerably thicker as it remodels-gradually, the bone will drift back, but it will have a bend in