Homeostasis & Body Temperature
Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for enzyme action and cell function, in response to internal and external changes. In humans, automatic control systems using nervous and hormonal responses regulate core body temperature, blood glucose concentration, and water levels.
- Homeostasis
- Maintaining a stable internal environment.
- Negative feedback
- A mechanism that restores a system to its normal level when it deviates from the norm.
- Thermoregulation
- The control of body temperature.
Interactive Human Body & Cell Structure Explorer
Click any internal organ or organelle to inspect its structure, toggle organs on/off to see what happens, or test yourself in Quiz Mode.
Heart (Double Circulatory Pump)
Structure & Function:
Pumps blood in a double circulatory system: the right ventricle pumps deoxygenated blood to the lungs, and the thick muscular left ventricle pumps oxygenated blood at high pressure around the whole body.
Key Exam Mark-Scheme Point:
Exam tip: The left ventricle has a much thicker muscular wall than the right ventricle because it must pump blood at high pressure all the way around the entire body, not just to the lungs.
What happens if this organ fails or is removed?
Without pressure from the heart, blood flow stops immediately. Oxygen and glucose cannot reach tissues, and waste carbon dioxide cannot be removed.
Tip: Use the “Simulate Organ Failure” button above to see how each organ system depends on the others to maintain homeostasis and cellular respiration.
Key Concepts & Exam Definitions (6)
- Homeostasis
- Maintaining a stable internal environment.
- Negative feedback
- A mechanism that restores a system to its normal level when it deviates from the norm.
- Thermoregulation
- The control of body temperature.
- Vasodilation
- Widening of blood vessels near the skin surface to increase heat loss.
- Vasoconstriction
- Narrowing of blood vessels near the skin surface to reduce heat loss.
- Insulin
- A hormone that lowers blood glucose levels.
Quick-Fire Flashcards (5)
Click any card to check the answer, then mark it as Known to track your progress.
What is the normal human body temperature?
What happens to blood vessels in the skin when the body is too hot?
How does sweating cool the body?
What happens to skeletal muscles when the body is too cold?
Which organ detects changes in blood glucose levels?
Exam-Style Questions & Mark Schemes (3)
Write or think through your answer first, then click Check Mark Scheme to see the exact points examiners award marks for.
- Q1
Explain how the body responds when its internal temperature rises above 37°C.
Click “Check Mark Scheme” to compare your answer, The thermoregulatory centre detects the change. It triggers vasodilation of blood vessels near the skin, increasing heat loss. Sweat glands produce more sweat, which evaporates and cools the body.
- Q2
Describe the process of negative feedback.
Click “Check Mark Scheme” to compare your answer, A receptor detects a change away from the normal level. An effector responds to counteract the change and restore the original level, at which point the response is turned off.
- Q3
Why is it important to keep body temperature at 37°C?
Click “Check Mark Scheme” to compare your answer, It is the optimum temperature for enzymes in the human body to work; higher temperatures would denature them, and lower temperatures would slow reactions down too much.
Common Exam Questions (4)
What is homeostasis?
Homeostasis is the maintenance of a constant internal environment within the body despite changes in external conditions or physical activity.
Why is homeostasis important?
Cells and metabolic reactions rely on enzymes that only function effectively within narrow ranges of temperature (around 37°C) and pH, and cells require steady water and glucose potentials to avoid osmotic damage.
What part of the brain controls body temperature?
Body temperature is monitored and controlled by the thermoregulatory centre located in the hypothalamus of the brain, which contains receptors sensitive to the temperature of the blood.
What does the body regulate through homeostasis?
In the human body, homeostasis regulates three main internal variables: core body temperature (37°C), blood glucose concentration, and blood water and ion content (osmoregulation).
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