PHSI2006 Study Guide - Midterm Guide: Spasm, Depolarization, Tetany

• School: University of Sydney
• Department: Physiology
• Course: PHSI2006
• Professor: phsi2006

Document Summary

Calcitonin, parathyroid hormone and fgf are the three hormones that regulated mineral metabolism. Must stay in this narrow range: about half the blood circulates in the ionised form of calcium (50%) (includes diffusible and also complexed ca2+) ! There are consequences of having too high or too low calcium. This refers to calcium concentrations in the blood and ecf not intracellular calcium involved in cell signaling: the calcium concentrations can affect the shape of proteins e. g. ion channels. Decreased calcium: decreased ca2+ ecf in the short term causes increased na ion channel permeability. It doesn"t take much more for a full depolarisation to occur so they can go off without being stimulated to do so. High calcium: short term: decreases sodium permeability! leads to hyperpolarization which makes it harder to depolarise nerves and muscles. * calcium is filtered by the kidney and obligatory urine calcium loss 150-