Sample interview questions: Can you explain the concept of homeostasis and its significance in physiology?
Sample answer:
- Homeostasis:
- Definition: The ability of an organism or cell to maintain a relatively stable internal environment despite fluctuations in the external environment.
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Importance: Homeostasis is essential for maintaining proper physiological functioning, as many biochemical reactions within cells rely on specific temperature, pH, and ion concentrations.
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Mechanisms of Homeostasis:
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Negative Feedback Mechanisms:
- Most common type of homeostasis
- Works by counteracting any deviation from the set point.
- For example, if body temperature rises, sweating increases to cool the body and bring temperature back to the set point.
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Positive Feedback Mechanisms:
- Less common, but essential in certain physiological processes.
- Amplifies the initial response rather than counteracting it.
- For example, the release of oxytocin during birth stimulates uterine contractions, which further stimulates the release of oxytocin, leading to stronger contractions.
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Homeostasis in Different Physiological Systems:
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Temperature Regulation:
- Body temperature is tightly regulated around a set point of 37°C (98.6°F).
- When body temperature rises, sweating and vasodilation increase to dissipate heat.
- When body temperature drops, shivering and vasoconstriction are triggered to generate and conserve heat.
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pH Regulation:
- Blood pH is maintained within a narrow range of 7.35-7.45.
- When blood pH decreases (acidosis), the respiratory rate increases to expel more CO2, raising pH.
- When blood pH increases (alkalosis), the respiratory rate decreases, and the kidneys excrete more bicarbonate, lowering pH.
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Blood Pressure Regulation: Read full answer