KNES 210 Lecture Notes - Lecture 2: Vo2 Max, Necrosis, Hematocrit
12 Sep 2016
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Homeostasis: set point, negative feedback, keep internal environment in chick while the external environment is changing, negative feedback. Thermoreceptors in the hypothalamus monitor core body temperature. Thermoreceptors on the skin monitor external temperature: too hot. Skin capillaries vasodilate removes heat via convection and radiation. Sweat removes heat via evaporation: too cold. Vasodilation occurs in skin blood vessels so more heat is lost from the skin. Sweat glands become active, increasing evaporative heat loss. Vasoconstriction occurs in skin blood vessels so less heat is lost to the environment. Skeletal muscles are activated, causing shivering, which increases metabolism and generates heat. Increased metabolic heat production: core temperature can go above 104 f. Impairs performance: competition for blood flow (skin for cooling) Excessive sweating: can lead to dehydration (loss of blood plasma, some blood must be shunted to skin to cool off the body. Lack of moving air reduces heat removal from the skin. Air movement is critical for effective cooling: humidity.
