Aim
Investigate the responses of the human body to extremes of ambient temperature.
Materials (2 marks)
• Oral thermometer
• Skin thermometer
• Alcohol swaps
• Stop watch
• Heater x2
• Cooler room
• Sleeping bag
• Minimal clothes (singlet and short)
• Warm clothes (4x jumpers, 3x pants, gloves, explorer sock, Ugg boots and scarfs)
• Ice cream
• Spoon
• Hot chocolate
• Marshmallows
• Milk
• Kettle
• Water
Risks
What are the risks in doing this experiment? How can you manage these risks to stay safe?
Volunteer may start to feel unwell when experiencing extremes in temperature. Cease activity immediately and assist volunteer in regaining normal body temperature. Note: Do not try to correct hypothermia with rapid temperature change. Try to
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Summarise the corresponding changes observed in the subjects. (2 marks)
5. Was your hypothesis supported by the data? Restate or modify your hypothesis in light of the results. (2 marks)
Yes. The core temperature will not be affected by extremes of ambient temperature due to homeostasis acting to prevent a core temperature change. The skin temperature will mimic that of the ambient temperature.
6. Explain the probable mechanisms in your subjects that brought about the above changes. (6 marks)
Regulation of body temperature is controlled by homeostasis. As humans, we maintain a relatively constant internal body temperature independent of the external temperature. The internal temperature of humans is approximately 37 °C. Any organism that can control its internal temperature is known as homoeothermic. Metabolic processes require an optimal temperature. At temperatures higher or lower than 37 °C, enzymes will not function optimally. Too high - they denature, too low - they will slow down the rate at which metabolic processes proceed. Using the homeostasis model the process must have a stimulus, a receptor, a co-ordinating centre, a response and then negative feedback. The hypothalamus is the temperature-regulating centre of the brain. It contains receptors which are sensitive to the temperature of the blood flowing through the brain. There are also temperature sensitive receptors in the skin also feedback information to the hypothalamus about the temperature of the skin surface. Changes in core body temperature cause the hypothalamus to send nerve impulses to the sweat glands, muscles and blood vessels to raise or lower the temperature. If the core temperature goes up the body loses heat to bring it down again using the sweat as an evaporative air con. If the core temperature goes down the body will conserve and even generate heat to bring it up again by shivering and moving around a