Biology Form 5 Chapter 3 - Coordination & Response Part 5 - Body Temperature Regulation
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Biology Form 5 Chapter 3 - Coordination & Response Part 5 - Body Temperature Regulation
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Biology Form 5 Chapter 3 - Coordination & Response Part 5 - Body Temperature Regulation
- 1. BIOLOGY FORM 5 CHAPTER 3 COORDINATION & RESPONSE PART 5
- 2. LEARNING OBJECTIVES 3.4 Synthesising the concept of homeostasis in humans LEARNING OUTCOMES explain the necessity to maintain an optimal physical and chemical condition in the internal environment state the meaning of homeostasis, design an experiment to study the effect of different quantities of water intake on urine output, relate changes in blood osmotic pressure to urine output, describe the formation of urine, relate the formation of urine to excretion, describe briefly the mechanism of osmoregulation, predict the consequences of impaired kidney function, describe the regulation of blood sugar level, describe the regulation of body temperature, conceptualise homeostasis.
- 4. THERMOREGULATION How we keep (or maintain) a steady body temperature. Mammals are endothermic homeotherms (warm blooded) They regulate their own body temperature.
- 5. To provide the optimum conditions for enzyme-catalysed reactions to be carried out. Why do we need to regulate: Internal body temperature
- 6. In humans it is the core body temperature which is maintained by homeostasis. Temperature Regulation
- 7. Body Temperature Normal internal body temperature is 370C. Temperatures above this: denature enzymes and block metabolic pathways Temperatures below this: slow down metabolism and affect the brain.
- 8. Body Temperature Control The hypothalamus acts as a thermostat and receives nerve impulses from heat and cold thermoreceptors in the skin. There are also receptors in the hypothalamus- called central thermoreceptors. These detect changes in blood temperature.
- 10. IT’S HOT
- 11. Correction of overheating 1. Detected by thermoreceptors in the hypothalamus impulses thermo regulatory centre in hypothalamus triggers effectors 2. Causes vasodilation. 3. Sweating 4. Hair lies flat
- 12. If the temperature rises, the blood vessel dilates (gets bigger). Vasodilation This means more heat is lost from the surface of the skin
- 13. Sweating When your body is hot, sweat glands are stimulated to release sweat. The liquid sweat turns into a gas (it evaporates) To do this, it needs heat. It gets that heat from your skin. As your skin loses heat, it cools down.
- 15. Cooling down When it's hot and you need to cool down, muscles at each hair relax. Hairs lie close to the skin. Air does not act as an insulating layer.
- 17. ITS COLD
- 18. If you are cold, What mechanisms are there to warm the body up?
- 19. Correction of overcooling 1. Detected by thermoreceptors in the hypothalamus impulses thermo regulatory centre in hypothalamus triggers effectors 2. Causes vasoconstriction. 3. Decreased sweating 4. Shivering
- 20. If the temperature falls, the blood vessel constricts (gets shut off). This means less heat is lost from the surface of the skin
- 21. Keeping warm When it's cold, the muscle contracts pulls the hair up. A layer of warm air accumulates around the hair and insulates the organism. Heat retained
- 23. No Sweating
- 24. Shivering How does it work?
- 25. Penguins huddling to keep warm
- 26. Animation
- 29. Metabolic changes Adrenal gland secretes adrenaline Thyroid gland secretes thyroxine Metabolic rate increases more heat released Converts glycogen glucose
- 30. ANIMATION
- 31. Fill in the blanks
- 32. Regulating Body Temperature - on a Hot Day
- 33. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 34 Stimulus Blood and skin temperatures rise Regulating Body Temperature - on a Hot Day
- 34. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 35 Stimulus Blood and skin temperatures rise Receptor Temperature receptors detect changes and send nerve impulses to the brain Regulating Body Temperature - on a Hot Day
- 35. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 36 Stimulus Blood and skin temperatures rise blood capillaries hair follicle hair arteriole erector muscle Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Regulating Body Temperature - on a Hot Day
- 36. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 37 Stimulus Blood and skin temperatures rise Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts arteriole capillariesskin surface Arterioles in skin dilate 1 More blood flows to capillaries in skin 2 3 Greater heat loss 4 Shunt vessels constrict Regulating Body Temperature - on a Hot Day
- 37. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 38 Stimulus Blood and skin temperatures rise Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts sweat duct sweat pore sweat gland Sweat glands more active Sweat production increases More latent heat lost as sweat evaporates 6 7 5 Regulating Body Temperature - on a Hot Day Receptor Temperature receptors detect changes and send nerve impulses to the brain
- 38. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 39 Stimulus Blood and skin temperatures rise Hair erector muscles in skin relax erector muscle blood capillaries hair follicle hair arteriole 8 Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Regulating Body Temperature - on a Hot Day
- 39. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 40 Stimulus Blood and skin temperatures rise Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Corrective Mechanism Increase in heat loss and decrease in heat production Regulating Body Temperature - on a Hot Day
- 40. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 41 Stimulus Blood and skin temperatures rise Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Corrective Mechanism Increase in heat loss and decrease in heat production Decreased metabolic rate reduces heat production Regulating Body Temperature - on a Hot Day
- 41. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 42 Stimulus Blood and skin temperatures rise Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Corrective Mechanism Increase in heat loss and decrease in heat production Blood temperature returns to normal levels Decreased metabolic rate reduces heat production Regulating Body Temperature - on a Hot Day
- 42. 8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 43 Stimulus Blood and skin temperatures rise Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Corrective Mechanism Increase in heat loss and decrease in heat production Blood temperature returns to normal levels Negative feedback Decreased metabolic rate reduces heat production Regulating Body Temperature - on a Hot Day
- 43. Regulating Body Temperature - on a Cold Day
- 44. Stimulus Blood and skin temperatures fall Regulating Body Temperature - on a Cold Day
- 45. Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Regulating Body Temperature - on a Cold Day
- 46. blood capillaries arteriole hair hair follicle Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts erector muscles Regulating Body Temperature - on a Cold Day
- 47. Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Less blood flows to capillaries in skin Arterioles in skin constrict Shunt vessels dilate skin surface capillaries arteriole 1 2 3 Less heat loss 4 Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Regulating Body Temperature - on a Cold Day
- 48. Sweat glands less active Sweat production decreases Less latent heat lost sweat pore sweat duct sweat gland Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts 56 7 Regulating Body Temperature - on a Cold Day
- 49. Hair erector muscles in skin contract erector muscles blood capillaries arteriole hair hair follicle Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts 8 Regulating Body Temperature - on a Cold Day
- 50. Shivering occurs when insufficient heat is produced Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Corrective Mechanism Decrease in heat loss and increase in heat production Regulating Body Temperature - on a Cold Day
- 51. Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Corrective Mechanism Decrease in heat loss and increase in heat production Increased metabolic rate increases heat production Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Regulating Body Temperature - on a Cold Day
- 52. Blood temperature returns to normal levels Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Corrective Mechanism Decrease in heat loss and increase in heat production Increased metabolic rate increases heat production Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts Regulating Body Temperature - on a Cold Day
- 53. Regulating Body Temperature - on a Cold Day Corrective Mechanism Decrease in heat loss and increase in heat production Increased metabolic rate increases heat production Blood temperature returns to normal levels Negative feedback Stimulus Blood and skin temperatures fall Receptor Temperature receptors detect changes and send nerve impulses to the brain Hypothalamus of brain is stimulated and sends nerve impulses to relevant body parts
- 54. 1. Receptors Nerve endings in skin send message to the brain about the external environment. Blood temperature changes detected by temperature receptors in brain Body Temperature Above 37°C 3. Effectors produce response •Sweating •Hairs lie flat •Vasodilation (blood vessels closest to surface of the skin widen) Body Temperature Below 37°C 3. Effectors produce response •Shivering •Hairs stand up •Vasoconstriction (blood vessels closest to the surface of the skin narrow) 2. Processing Centre The hypothalamus processes the information from the temperature receptors and co-ordinates the response. 2. Processing Centre The hypothalamus processes the information from the temperature receptors and co-ordinates the response. 4. Levels return to Normal 37°C
- 55. The EnD