Susan, a 23-year-old student, went on a trip to a health spa with friends. Susan
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Question
Susan, a 23-year-old student, went on a trip to a health spa with friends. Susan sat in a sauna at a temperature of 170 degree F (77 degree C) for ten minutes. During this time, homeostatic mechanisms led to her body temperature remaining relatively constant. What is homeostasis? What factors or conditions of the internal body environment are monitored and regulated as part of homeostasis? What is meant by the terms 'set point' and 'set point range'? What is the set point temperature for the body? Describe the basic components that forma homeostatic feedback system. What type of feedback system would be involved in regulating Susan's temperature? What are the effectors that help to reduce Susan's body temperature? What is their response to increased body temperature?Explanation / Answer
1A) Homeostasis, any self-regulating process by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival. If homeostasis is successful, life continues; if unsuccessful, disaster or death ensues.
2A) The control of body temperature in humans is a good example of homeostasis in a biological system. In humans, normal body temperature fluctuates around the value of 37 °C (98.6 °F), but various factors can affect this value, including exposure, hormones, metabolic rate, and disease, leading to excessively high or low temperatures. The body’s temperature regulation is controlled by a region in the brain called the hypothalamus. Feedback about body temperature is carried through the bloodstream to the brain and results in compensatory adjustments in the breathing rate, the level of blood sugar, and the metabolic rate. Heat loss in humans is aided by reduction of activity, by perspiration, and by heat-exchange mechanisms that permit larger amounts of blood to circulate near the skin surface. Heat loss is reduced by insulation, decreased circulation to the skin, and cultural modification such as the use of clothing, shelter, and external heat sources. The range between high and low body temperature levels constitutesthe homeostatic plateau—the “normal” range that sustains life. As either of the two extremes is approached, corrective action (through negative feedback) returns the system to the normal range.
3A) SET POINT: A set point is a theory that states everyone's body has a genetically determined range of weight and temperature that their body will try to maintain to stay at optimal health. This means if Susan has a weight set point of 136 pounds, her body will try to stay around that weight. If she eats less and exercises more, her body's metabolism will slow down. If Susan eats more and exercises less, her body's metabolism will speed up. This does not mean Susan can't ever weigh over 145 pounds or under 120 pounds. It means that her body will attempt to compensate for Susan's eating habits in order to stay in that range.
Proponents of this theory encourage individuals to stay at their body's set point and to accept it despite social pressures to be thin. They believe that the reason people have difficulty losing or gaining weight is because their weight goals are outside of their set point range.
SET POINT RANGE: Range of body weight where set point work is called set point range. EX.Susan can't ever weigh over 145 pounds or under 120 pounds.Here the range is 120-145 ponds
4A) At the normal Set point temperature, as measured with an oral thermometer, will be approximately 37°C (98.6°F). If body temperature rises above 37.2°C, activity in the control center targets two effectors: (1) muscle tissue in the walls of blood vessels supplying the skin and (2) sweat glands.
5A)
Every organ in the body contributes to homeostasis. A complex set of chemical, thermal, and neural factors interact in complex ways, both helping and hindering the body while it works to maintain homeostasis.
Homeostatic control
To maintain homeostasis, communication within the body is essential. The image below is an example of how a homeostatic control system works. Here is a brief explanation:
Good example of a positive feedback mechanism is blood clotting. Once a vessel is damaged, platelets start to cling to the injured site and release chemicals that attract more platelets. The platelets continue to pile up and release chemicals until a clot is formed.
6A) Negative feedback mechanisms : These mechanisms change the variable back to its original state or “ideal value”.
7A) Factors help to reduce susans body temperature and response to increase in temperature
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