HOMEOSTASIS ESSAY “Homeostasis is the maintenance of a constant internal environment, within narrow limits, despite a changing external environment.” Nomsa is sitting in class on a particular day and looks at the wall thermometer showing 43oC. Discuss the processes and mechanisms that are involved in thermoregulation and osmoregulation in her body on that particular day. Content: 17 Synthesis : 3 THERMOREGULATION • When the environmental temperature is high, receptors in the skin detect this • increased blood temperature is detected by the heat loss centre of the hypothalamus. • The hypothalamus sends impulses to the skin causing the surface blood vessels to dilate/increase in diameter/vasodilation occurs. • More blood flows to the skin and therefore more heat is lost to the environment. The sweat glands are stimulated to produce more sweat thereby causing heat loss through evaporation • Thereby causing the body to cool down Any 8 OSMOREGULATION • On a hot day a person loses water through sweating, thereby decreasing the amount of water in the blood. • Osmoreceptors detect this and cause the hypothalamus to release more ADH (Antidiuretic hormone) into the blood. • ADH cause an increase in the permeability of the renal tubules to water • More water is reabsorbed in the kidneys • Urine becomes more concentrated/decrease in volume • Water levels are restored to normal Any 9 LIFE SCIENCE ACADEMICS - 2014
Posted on: Wed, 19 Nov 2014 16:55:04 +0000
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