EXSS2021 Lecture Notes - Lecture 8: Posterior Pituitary, Extracellular Fluid, Heat Illness

• School: University of Sydney
• Department: Exercise and Sport Science
• Course: EXSS2021
• Professor: Helen O'Connor

Document Summary

Increased hr, reduced performance, reduced gastric emptying, vomiting, heat illness. Voluntary dehydration: the failure o fully replace fluid levels. Hyponatremia: plasma volume below normal range > overdrinking and inadequate secretion of. Skin and sweat glands: ingested > bloodstream > cell membranes > intracellular. Water molecules cant cross lipid bilayer via diffusion > facilitated diffusion is needed through transport protein. Water moves across membrane to alter the concentration. Dehydration = increased blood osmolarity = osmoreceptors in hypothalamus. > increased antidiuretic hormone in posterior pituitary gland. + vasoconstriction to increase blood pressure via stimulation of decreased blood pressure causing release of angiotensin 1 > 2. Decreased plasma volume via decreased metabolic waste, increased heat = sweat, increased pressure in capillaries. Increased heat production > removal of heat via sweat > fluid deficit > hypohydration. > fluid deficits lead to decreased sweat production and skin blood flow. Heat exhaustion = dizzy, headache, nausea, high rectal temp, pale, still slight sweating.