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Describe how the human body maintains the temperature and carbon dioxide concentration in the blood when they rise above normal limits - NSC Life Sciences - Question 4 - 2020 - Paper 1
Question 4
Describe how the human body maintains the temperature and carbon dioxide concentration in the blood when they rise above normal limits. Also, describe the importanc... show full transcript
Worked Solution & Example Answer:Describe how the human body maintains the temperature and carbon dioxide concentration in the blood when they rise above normal limits - NSC Life Sciences - Question 4 - 2020 - Paper 1
Step 1
When temperature rises above normal (T)
Answer
When the body temperature rises above normal limits, several mechanisms are activated to restore homeostasis:
- Receptors are stimulated - Thermoreceptors detect the increase in temperature.
- Impulse transmission - These receptors send impulses to the hypothalamus, the body's thermoregulatory center.
- Vasodilation - The hypothalamus sends signals to the blood vessels in the skin and sweat glands, causing the blood vessels to dilate (vasodilation).
- Increased blood flow - More blood flow to the surface of the skin leads to greater heat loss from the body.
- Sweating - The sweat glands are stimulated to produce more sweat.
- Evaporation - As sweat evaporates, it absorbs heat from the body, further cooling it down.
- Return to normal - These processes continue until the temperature of the body returns to its normal range.
Step 2
When the carbon dioxide levels rise above normal (C)
Answer
Elevated levels of carbon dioxide in the blood trigger specific responses to regulate its concentration:
- Receptor activation - Receptor cells recognize the increased concentration of carbon dioxide in the blood.
- Impulse transmission - These receptors send impulses to the medulla oblongata, which is responsible for regulating breathing.
- Increased respiration - The medulla oblongata sends signals to the breathing muscles, prompting an increase in respiratory rate and depth.
- Cardiac response - An impulse is also sent to the heart to beat faster, enhancing the oxygen supply to tissues.
- Exhalation - More carbon dioxide is expelled from the lungs during this increased respiratory activity, thereby lowering its levels in the blood until normal levels are restored.
Step 3
Importance of carbon dioxide in regulating atmospheric temperature and its influence on global warming (A)
Answer
Carbon dioxide plays a crucial role in maintaining Earth's temperature and has implications for global warming:
- Greenhouse gas - Carbon dioxide acts as a greenhouse gas, trapping heat in the atmosphere which helps stabilize the planet's temperature.
- Heat retention - It prevents heat from escaping, maintaining a warm environment conducive to life on Earth. This phenomenon is referred to as the greenhouse effect.
- Life sustenance - It maintains climatic conditions necessary for supporting life.
- Rising levels - Increased carbon dioxide levels can amplify the greenhouse effect, leading to higher overall temperatures.
- Global warming impact - This excess heat contributes to variations in climate patterns, resulting in global warming and associated environmental changes.