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Homeostasis

Homeostasis. CAPS and EXAM GUIDELINES. CAPS. Homeostasis The process of maintaining a constant, optimal internal environment . Homeostasis negative feedback of: glucose , carbon dioxide; water and salts; Homeostasis

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Homeostasis

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  1. Homeostasis CAPS and EXAM GUIDELINES

  2. CAPS Homeostasis The process of maintaining a constant, optimal internal environment. Homeostasis negative feedback of: glucose, carbon dioxide; water and salts; Homeostasis thermoregulation: adaptations of human skin; sweating, vasodilatation, vasoconstriction.

  3. Exam Guidelines 2017 • Introduction • Homeostasis as the process of maintaining a constant, internal environment within narrow limits, despite changes that take place internally and externally. Learn • The conditions within cells depend on the conditions within the internal environment (tissue fluid). See slideshow and learn • Factors such as carbon dioxide, glucose, salt and water concentration, temperature and pH must be kept constant in the internal environment ( tissue fluid). See slide show and learn

  4. Tissue fluid – how is it formed? Why is it so important?

  5. Exam guidelines 2017 Homeostasis through negative feedback Negative feedback mechanism controlling the concentration of: • Glucose • Carbon dioxide • Water • Salts • NB know glands, hormones, target areas, responses – always use more/rises/increases and less/lowers/decreases in relevant descriptions

  6. Negative feedback

  7. Negative feedback mechanism controlling the concentration of: Glucose

  8. Negative feedback mechanism controlling the concentration of: Carbon dioxide

  9. Negative feedback mechanism controlling the concentration of: Water (Osmoregulation) p 177

  10. Negative feedback mechanism controlling the concentration of: Salts

  11. Exam guidelines 2017 • Thermoregulation/temperature control • Structure of the skin, using a diagram, with an emphasis on the parts involved in thermoregulationand know adaptations for effective temperature control • Role of each of the following in thermoregulation: • Sweating • Vasodilation • Vasoconstriction

  12. Structure of the skin, using a diagram, with an emphasis on the parts involved in thermoregulation.

  13. Too hot ie temperature rises above normal

  14. Too cold ie temperature drops below normal

  15. Thermoregulation/temperature control summary

  16. Temperature control comparison

  17. Role of sweating, vasodilation & vasoconstriction in temperature control • The body’s temperature is monitored by the hypothalamus. If you are too hot or too cold, the hypothalamus sends nerve impulses to the skin, which has three ways to either increase or decrease heat loss from the body’s surface: • If the body is too hot, glands under the skin secrete sweat onto the surface of the skin, to increase heat loss by evaporation. Sweat secretion stops when body temperature returns to normal. • Blood vessels supplying blood to the skin can swell or dilate - called vasodilation. This causes more heat to be carried by the blood to the skin, where heat can be lost to the air. • Blood vessels can shrink down again - called vasoconstriction. This reduces heat loss through the skin once the body’s temperature has returned to normal. ALSO • Muscles can also receive messages from the brain when you are cold. They respond by shivering, which warms you up. • Hairs on the skin trap more warm air if they are standing up, and less if they are lying flat. Tiny muscles in the skin can quickly pull the hairs upright to reduce heat loss, or lay them down flat to increase heat loss.

  18. Sources Mindset http://intranet/biology/LifeSciences12/documents/MindsetLearnHomeostasisTempRegulation.pdf A2 Homeostasis http://intranet/biology/LifeSciences12/documents/A2HomeostasisandThermoregulation.pdf BBC Bite size http://www.bbc.co.uk/bitesize/higher/biology/control_regulation/homeostatic_control/revision/1/ http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway_pre_2011/ourselves/5_staying_in_balance2.shtml PMG Biology https://pmgbiology.com/2014/05/29/skin-a-understanding-for-igcse-biology/ Science Aid https://scienceaid.net/biology/humans/homeostasis.html Shuters Top Class Life Sciences 12 Learners Book page 177 And https://www.slideshare.net/stvb2170/formation-of-tissue-fluid

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