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BIOLOGY FORM 5
CHAPTER 3
COORDINATION & RESPONSE PART 5
LEARNING OBJECTIVES
3.4 Synthesising the concept of homeostasis in humans
LEARNING OUTCOMES
 explain the necessity to mai...
THERMOREGULATION
How we keep (or maintain) a steady body temperature.
Mammals are
endothermic
homeotherms
(warm
blooded)
T...
 To provide the optimum conditions for
enzyme-catalysed reactions to be
carried out.
Why do we need to regulate:
Internal...
In humans it is the core
body temperature
which is maintained by
homeostasis.
Temperature Regulation
Body Temperature
 Normal internal body temperature
is 370C.
 Temperatures above this:
denature enzymes and block
metabol...
Body Temperature Control
 The hypothalamus
acts as a thermostat
and receives nerve
impulses from heat
and cold
thermorece...
SKIN STRUCTURE
IT’S HOT
Correction of overheating
1. Detected by thermoreceptors in the
hypothalamus impulses thermo
regulatory centre in hypoth...
If the temperature
rises, the blood
vessel dilates (gets
bigger).
Vasodilation
This means more heat is lost from the surfa...
Sweating
 When your body is hot,
sweat glands are stimulated
to release sweat.
 The liquid sweat turns into a
gas (it ev...
Sweating
The
skin
Cooling down
 When it's hot and you
need to cool down,
muscles at each hair
relax.
 Hairs lie close to the
skin.
 Air d...
ITS COLD
If you are cold,
What mechanisms are there to
warm the body up?
Correction of overcooling
1. Detected by thermoreceptors in the
hypothalamus  impulses thermo regulatory
centre in hypot...
If the temperature
falls, the blood
vessel constricts
(gets shut off).
This means less heat is lost from the surface of th...
Keeping warm
 When it's cold, the
muscle contracts
pulls the hair up.
 A layer of warm air
accumulates around
the hair a...
No Sweating
Shivering
How does it work?
Penguins huddling to keep warm
Animation
Metabolic changes
Adrenal gland
secretes adrenaline
Thyroid gland
secretes thyroxine
Metabolic rate increases  more heat ...
ANIMATION
Fill in the blanks
Regulating Body Temperature - on a Hot Day
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 34
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 35
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 36
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 37
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 38
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 39
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 40
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 41
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 42
Stimulus
Blood and skin
tempera...
8 June 2016Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 43
Stimulus
Blood and skin
tempera...
Regulating Body Temperature - on a Cold Day
Stimulus
Blood and skin
temperatures fall
Regulating Body Temperature - on a Cold Day
Stimulus
Blood and skin
temperatures fall
Receptor
Temperature receptors
detect changes and send
nerve impulses to the
bra...
blood capillaries
arteriole
hair hair follicle
Stimulus
Blood and skin
temperatures fall
Receptor
Temperature receptors
de...
Stimulus
Blood and skin
temperatures fall
Receptor
Temperature receptors
detect changes and send
nerve impulses to the
bra...
Sweat glands
less active
Sweat
production
decreases
Less latent heat lost
sweat pore
sweat duct
sweat gland
Stimulus
Blood...
Hair erector
muscles in
skin contract
erector muscles
blood capillaries
arteriole
hair hair follicle
Stimulus
Blood and sk...
Shivering occurs when
insufficient heat is produced
Stimulus
Blood and skin
temperatures fall
Receptor
Temperature recepto...
Stimulus
Blood and skin
temperatures fall
Receptor
Temperature receptors
detect changes and send
nerve impulses to the
bra...
Blood temperature
returns to normal levels
Stimulus
Blood and skin
temperatures fall
Receptor
Temperature receptors
detect...
Regulating Body Temperature - on a Cold Day
Corrective Mechanism
Decrease in heat loss
and increase in heat
production
Inc...
1. Receptors
Nerve endings in skin send
message to the brain about
the external environment.
Blood temperature changes
det...
The EnD
Biology Form 5 Chapter 3  - Coordination & Response  Part 5 - Body Temperature Regulation
Biology Form 5 Chapter 3  - Coordination & Response  Part 5 - Body Temperature Regulation
Biology Form 5 Chapter 3  - Coordination & Response  Part 5 - Body Temperature Regulation
Biology Form 5 Chapter 3  - Coordination & Response  Part 5 - Body Temperature Regulation
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

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Biology Form 5 Chapter 3 - Coordination & Response Part 5 - Body Temperature Regulation

  1. 1. BIOLOGY FORM 5 CHAPTER 3 COORDINATION & RESPONSE PART 5
  2. 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.
  3. 3. THERMOREGULATION How we keep (or maintain) a steady body temperature. Mammals are endothermic homeotherms (warm blooded) They regulate their own body temperature.
  4. 4.  To provide the optimum conditions for enzyme-catalysed reactions to be carried out. Why do we need to regulate: Internal body temperature
  5. 5. In humans it is the core body temperature which is maintained by homeostasis. Temperature Regulation
  6. 6. 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.
  7. 7. 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.
  8. 8. SKIN STRUCTURE
  9. 9. IT’S HOT
  10. 10. 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
  11. 11. If the temperature rises, the blood vessel dilates (gets bigger). Vasodilation This means more heat is lost from the surface of the skin
  12. 12. 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.
  13. 13. Sweating The skin
  14. 14. 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.
  15. 15. ITS COLD
  16. 16. If you are cold, What mechanisms are there to warm the body up?
  17. 17. 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
  18. 18. If the temperature falls, the blood vessel constricts (gets shut off). This means less heat is lost from the surface of the skin
  19. 19. 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
  20. 20. No Sweating
  21. 21. Shivering How does it work?
  22. 22. Penguins huddling to keep warm
  23. 23. Animation
  24. 24. Metabolic changes Adrenal gland secretes adrenaline Thyroid gland secretes thyroxine Metabolic rate increases  more heat released Converts glycogen  glucose
  25. 25. ANIMATION
  26. 26. Fill in the blanks
  27. 27. Regulating Body Temperature - on a Hot Day
  28. 28. 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
  29. 29. 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
  30. 30. 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
  31. 31. 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
  32. 32. 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
  33. 33. 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
  34. 34. 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
  35. 35. 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
  36. 36. 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
  37. 37. 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
  38. 38. Regulating Body Temperature - on a Cold Day
  39. 39. Stimulus Blood and skin temperatures fall Regulating Body Temperature - on a Cold Day
  40. 40. 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
  41. 41. 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
  42. 42. 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
  43. 43. 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
  44. 44. 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
  45. 45. 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
  46. 46. 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
  47. 47. 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
  48. 48. 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
  49. 49. 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
  50. 50. The EnD

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