Controlling body temperature
Introduced| English | Meaning |
|---|---|
| thermoregulation/ˌθɜːməʊˌreɡjʊˈleɪʃn/ | thermoregulation |
| sweating/ˈswetɪŋ/ | Releasing sweat that evaporates and cools the skin. |
| vasodilation/ˌvæsədɪˈleɪʃn/ | Widening of blood vessels, which can increase blood flow through them. |
| shivering/ˈʃɪvərɪŋ/ | Rapid involuntary muscle contractions that increase heat production when the body is cold. |
| vasoconstriction/ˌvæsəkənˈstrɪkʃn/ | The narrowing of blood vessels due to contraction of muscle in their walls. |
Staying at 37 °C
- Your enzymes work best at about 37 °C, so your body works hard to hold that temperature.
- This is thermoregulation 体温调节, controlled by the skin and brain.
When you are too hot, the body responds by:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Sweating and vasodilation lose heat.
Sweating cools you because:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Evaporation removes heat from the skin.
When you're too hot
- Sweating 出汗: water evaporates from the skin, taking heat away.
- Vasodilation 血管舒张: blood vessels near the skin widen, so more heat is lost.
Body temperature is held near 37°C by negative feedback
Controlling body temperature
sweat ↓ · shiver ↑
Body temperature returns to 37 °C: too hot → sweat; too cold → shiver.
When you are too cold, the body responds by:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Shivering generates heat; vasoconstriction keeps it.
Rapid muscle contractions that release heat when you are cold are called ______.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Shivering generates heat from respiration.
When you're too cold
- Shivering 颤抖: muscles contract rapidly, releasing heat from respiration.
- Vasoconstriction 血管收缩: skin blood vessels narrow, so less heat is lost.
Normal human body temperature is about how many °C?
Difficulty 2/5 · 140 coins + a small bonus on first completion today
About 37 °C — the optimum for enzymes.
Negative feedback again
- The brain detects the change and triggers the opposite response.
- This negative feedback keeps body temperature close to 37 °C.
Vasodilation doesn't move the vessels — it widens them. The blood vessels near the skin surface widen (dilate) to lose heat, or narrow (constrict) to keep it. They don't actually move up or down.
You've got it
- the body holds about 37 °C (best for enzymes) by negative feedback
- too hot: sweating and vasodilation (lose heat)
- too cold: shivering and vasoconstriction (keep heat)