Thermoregulation (4.1.1)

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What are the three ways that heat is transferred?
Conduction, convection and radiation.
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How does convection work?
Gas or liquid is heated, it becomes less dense and will rise through surrounding cooler air.
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How does radiation work?
Radiation travels in straight lines through air and absorbed by solid objects.
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How does conduction work?
Heat passes from one particle to another if they are next to each other.
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Why do we need to maintain our body temperature?
Changes can have an effect on the structure of enzymes, so the activity rate is affected. Enzymes work best at their optimum.
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What is an endotherm?
Can maintain the temperature of their body within narrow limits, independent of the fluctuating external environment.
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What is an ectotherm?
Rely on external environment for their temperature control. Their body temperature is linked to that of its surroundings.
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What animals are ectotherms?
Most animals except mammals and birds.
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Give 2 advantages of being an ectotherm.
Have more energy for hunting or growth. Don't have to feed as often.
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Give 3 disadvantages of being an ectotherm.
Can't adapt to new environments easily. Less active in cool conditions- more vulnerable. Need to prioritise body temperature- reduced productivity.
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What happens once ectotherms are warmed up and active?
Their muscles will generate heat as they contract during movement, so more heat is generated if they keep active.
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Give 4 ways ectotherms warm up.
Lie on hot objects- conduction. Change colour to absorb more heat. Huddle in groups. Expose body to sun, lie flat- increased surface area.
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Give 3 ways ectotherms cool down.
Alter position and shape to reduce surface area. Reduce activity so less heat is generated. Take shelter in shade.
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Give 3 advantages of being an endotherm.
Have a fairly constant body temperature. Can remain active in low temperatures. Successfully live in wide range of climates.
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Give 3 disadvantages of being an endotherm.
80% of food intake must be respired to generate heat. Lots of time spent hunting. Need to eat more, and more often.
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What is the hypothalamus?
A part of the brain which contains thermoreceptors and constantly monitors the temperature of the blood flowing through it.
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What can affect core body temperature?
Time of day, stage of menstrual cycle, activity levels.
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What are peripheral temperature receptors?
Found in skin, and monitor the temperature at the extremities of the body.
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How do the sweat glands respond to different temperatures?
Too hot- more sweat secreted. Water in sweat evaporates, taking heat from body. This has a cooling effect. Too cold- less sweat secreted.
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How do the airways respond to different temperatures?
Too hot- panting leads to evaporation of water from lungs/tongue. Too cold- no panting.
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How do skin hairs respond to different temperatures?
Too hot- lie flat, no insulating effect. Too cold- stand on end (piloerection) giving an insulating effect by trapping a layer of air.
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How do arterioles respond to different temperatures?
Too hot- vasodilation so more blood blow to capillaries, heat radiates away from skin's surface. Too cold- vasoconstriction- less blood flow to capillaries.
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How do skeletal muscles respond to different temperatures?
Too hot- no shivering. Too cold- shivering, which is the spontaneous contraction and relaxing of muscles to generate heat.
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What behavioural mechanisms can warm up endotherms?
Put more clothes on, eat hot food, move to warmer place.
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Describe what happens when body temperature is too high.
Negative feedback. Hypothalamus detects change. Nervous system and hormones carry signal to skin, liver and muscles. Vasodilation, decreased metabolic rate, sweating. Less heat generated & more heat lost. Temperature returned to normal level.
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Describe what happens when body temperature is too low.
Negative feedback. Hypothalamus detects change. Nervous system & hormones carry signals to skin, liver & muscles. Shivering, erect hairs, vasoconstriction, increased metabolic rate. More heat generated & less lost. Temperature rises to normal level.
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How is adrenaline involved in thermoregulation?
Short term response to increase metabolic rate to generate heat if needed.
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How is thyroxine involved in thermoregulation?
Production is increased if subjected to long term cool conditions. Increases metabolic rate to generate heat.
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Other cards in this set

Card 2

Front

How does convection work?

Back

Gas or liquid is heated, it becomes less dense and will rise through surrounding cooler air.

Card 3

Front

How does radiation work?

Back

Preview of the front of card 3

Card 4

Front

How does conduction work?

Back

Preview of the front of card 4

Card 5

Front

Why do we need to maintain our body temperature?

Back

Preview of the front of card 5
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