Biology 8 Lesson 33: Body temperature
1. Summary of theory
1.1. Body temperature
- Body temperature is the body temperature.
- Body temperature is always stable at 370C (doesn’t fluctuate more than 0.5oC) due to the balance between heat generation and heat loss.
- Body temperature reflects health status.
1.2. Mechanisms of body temperature regulation
a. Role of skin in body temperature regulation
Skin plays an important role in body temperature regulation
- When it’s hot: Skin capillaries dilate, blood flow through the skin is more, creating conditions for the body to increase heat and increase sweating, evaporation of sweat will take away some of the body’s heat.
- When it’s cold: Skin capillaries constrict, blood flow through the skin is less, so the skin turns purple. At the same time, the leg muscles contract, so goosebumps reduce heat loss through the skin
All activities of body temperature regulation are reflexes under the control of the nervous system
b. The role of the nervous system in temperature regulation
The nervous system plays a key role in body temperature regulation
The nervous system regulates heat loss by:
Increases and decreases in catabolism in cells
Reactions to constrict and dilate blood vessels under the skin
Increase and decrease sweating
Contraction and stretching of leg muscles
1.3. Anti-heat, anti-cold method
– The ambient temperature is high but not ventilated, the heat release and perspiration are stopped, causing the body temperature to rise and easily catch a cold.
– If you go to the sun or have just finished doing heavy work, your body temperature is high, but if you take a bath right away or sit down in the draft, you may catch a fever.
– In the cold season, the body loses a lot of heat without keeping the body warm enough to catch a cold.
We need to regularly fight heat and cold to keep our bodies healthy.
2. Illustrated exercise
Please explain the sentences:
- “When it’s hot, you’ll be thirsty, when it’s cold, you’ll be hungry.”
- “Cold shivering”.
- When it is hot, the ambient temperature is high, the air humidity is low, the body produces a lot of sweat, reducing the body’s heat. That explains why: It’s hot and thirsty.
- When it is cold, the body increases the metabolism of matter and energy to increase body heat. That explains why: It’s cold and hungry.
- When it is too cold, the muscles contract continuously, causing a shivering reflex to increase heat production.
3.1. Essay exercises
Question 1: Describe the mechanism of body temperature regulation in the following cases: hot weather, hot weather and cold weather.
Verse 2: To prevent heat, cold, in work and daily life, what points should I pay attention to?
Question 3: How is body temperature measured and for what purpose?
3.2. Multiple choice exercises
Question 1: What is body temperature?
A. Is body temperature
B. Is the body’s heat-radiating process
C. Is the body’s heat-collecting process
D. Is the body’s heat exchange process
Verse 2: What is a stable body temperature?
A. The amount of heat released and collected is balanced with each other
B. The amount of heat released is consistent with the excess heat of the body
C. The amount of heat collected is just enough to provide energy for the body’s vital activities
D. Body heat is not lost.
Question 3: Which organ plays the most important role in temperature regulation?
Verse 4: When it is hot or hard working, the body often sweats?
A. When it’s hot and when you work hard, the capillaries in the skin dilate to help dissipate heat quickly, and at the same time increase perspiration, evaporation of sweat will take away some of the body’s heat.
B. When it’s hot and when you work hard, the capillaries in the skin shrink to help retain heat, and at the same time increase perspiration, evaporating sweat will take away some of the body’s heat.
C. When it is hot and when working hard, the capillaries in the skin dilate to help retain heat. When the temperature is at its maximum, sweating, evaporation will take away some of the body’s heat.
D. When it’s hot and when doing hard work, the capillaries in the skin contract to help dissipate heat quickly, and at the same time, increase perspiration, the evaporation of sweat will take away some of the body’s heat.
Question 5: Which of the following is true about the body’s response to cold weather?
A. Capillaries constrict
B. Leg muscles contract
C. Often has a tremor reflex
D. All the answers above
After completing this lesson, you should:
- Describe the role of the skin and nervous system in temperature regulation.
- Know how to fight heat and cold for the body to protect health.