PHYSICS 102 Lecture Notes - Lecture 15: Extracellular Fluid, Homeostasis, Tetany
Document Summary
Calcium: uses, structural component of bones and teeth, maintains normal excitability of nerve and muscle cells. Involved in neurotransmitter and hormone release: muscle contraction (skeletal and cardiac, activation of many enzymes, coagulation of blood, milk production, occurrence. In nature: does not exist freely, bound to something else, occurs mostly in soil systems as limestone, gypsum and fluorite. Git to increased production of calcium transport proteins: leads to an increase in calcium uptake from git, the only mechanism that can increase calcium stores, bone: Increases the secretion of osteoclast activating factors: kidney, minor effect in decreasing urinary loss of calcium, works by increasing how much calcium we can absorb from food, kidney failure patients. Calcitonin: secreted by the c-cells (parafollicular cells) of the thyroid gland, lowers the level of free plasma calcium. Inhibition of osteoclasts activity: bone reabsorption reduced (direct effect) Increased excretion of calcium and phosphate by the kidneys: osteoporosis.
