5.15 Thermoregulation Flashcards
What is thermoregulation?
The control of our internal body temperature
What part of your brain acts as your own personal thermostat?
Hypothalamus
How does the hypothalamus detect body temperature?
It contains receptors that are sensitive to the blood temperature in the brain. It also receives impulses from receptors in the skin (nerve endings) that provide information about the external temperature.
What is the thermoregulatory centre?
It is part of the hypothalamus within our brain and it acts as a thermostat for our body.
What does the hypothalamus do when it detects a change?
It causes a response in the dermis (deep layer of the skin)
What does your body too when it is too hot? (3)
1) Erector muscles relax, so hairs lie flat.
2) Lots of sweat (containing water and salts) is produced. When the sweat evaporates, it transfers energy from your skin to the environment, cooling you down.
3) Muscles in the walls of blood vessels close to the surface of the skin relax. This causes the blood vessels to dilate (widen) and is called vasodilation. It allows more blood to flow near the surface, so it can transfer more energy into the surroundings, which cools you down.
What does your body do when it is too cold? (4)
1) Erector muscles contract. Hairs stand on end to trap an insulating layer of air, which helps keep you warm.
2) Very little sweat is produced.
3) Muscles in the walls of blood vessels near the surface of the skin contract. This causes the vessels to constrict (narrow) and is called vasoconstriction. It means less blood flows near the surface, so less energy is transferred to the surroundings.
4) When you’re too cold, you shiver too (your muscles contract automatically). This needs respiration, which transfers some energy to warm the body.
What type of feedback is involved in thermoregulation?
Negative feedback
Explain how shivering warms the body
Shivering involves muscles contracting and relaxing automatically. This requires a lot of energy from respiration, which in the process releases a lot of heat energy as waste.
How does sweat keep us cool?
As sweat evaporates, it removes heat energy from the skin
How would you model two antagonistic effectors in the body? (3)
1) Place a bunsen burner on a heat-proof mat, and a tripod and gauze over the bunsen burner. Put a beaker of water on top of the tripod.
2) Use a thermometer to measure the temperature of the water. Then use the bunsen burger to carefully heat the water to 40 degrees.
3) When the temperature of the water gets above 40 degrees, turn off the bunsen burner and carefully add an ice cube to the water. Give it a bit of a stir. By adding the ice cube, your modelling an antagonistic effector - the cooling effect of the ice cube works in opposition to the heating effect of the bunsen burner.
3) Use a stopwatch to record how long it takes for the water to return to 40 degrees.
