BIOL-242 Lecture Notes - Lecture 58: Brown Adipose Tissue, Sympathetic Nervous System, Skeletal Muscle
16 Jun 2020
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Chapter 24 part 10 | hypothalamus in heat mechanisms. Preoptic region of hypothalamus main integrating center for thermoregulation. Central thermoreceptors (some in hypothalamus) in core. Shivering heat from skeletal muscle activity. Increased metabolic rate via epinephrine and norepinephrine. Increasing physical activity (jumping up and down) Heat-promoting center inhibited dilation of cutaneous blood vessels. Reducing activity and seeking a cooler environment. Positive-feedback mechanism ( heat stroke ) begins at core temperature of. Due to dehydration and low blood pressure. May progress to heat stroke if not cooled and rehydrated promptly. Shivering stops at core temperature of 30 - 32c. Can progress to coma and death by cardiac arrest at ~ 21c. Due to infection (also cancer, allergies, or cns injuries) Natural body defenses or antibiotics reverse disease process. Cryogens (e. g. , vasopressin) reset thermostat to lower (normal) level heat-loss mechanisms temperature falls. Cells cannot use amino acid phenylalanine neurotoxins in blood. Brain damage and retardation within few months.
