S4.5.6 For the adult
Temperature and water balance
You sweat when it is hot, shiver when it is cold, and pass dark urine when you have drunk little. On a hot day, which of these cools your body?
What this chapter teaches
The body keeps its temperature near 37 °C by negative feedback. When hot, sweat evaporates and skin vessels widen. When cold, the vessels narrow and the muscles shiver. The kidneys filter the blood, take back what the body needs and control the water in urine with ADH from the pituitary gland.
Three questions to ask
There is no one right wording. Listen for the idea.
- What happens in your skin when you are hot, and what happens when you are cold?
- Why does sweat cool you, and why does a damp day feel hotter?
- Why is your urine dark when you have drunk little, and what hormone is involved?
After the chapter, the learner can
- Explain how sweating and shivering keep body temperature steady
- Explain how the kidneys control the water in the body
What they copy into their notebook
Hot: sweat evaporates, skin vessels widen. Cold: vessels narrow, shivering. Kidneys filter blood, take back what is needed. ADH from the pituitary makes them take back more water.