Questions and Answers
What is homeostasis?
What is a setpoint?
At what body temperature is a person considered to have a fever?
Which physiological condition is NOT considered in maintaining homeostasis?
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What happens when body temperature rises above the normal range during exercise?
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Which of the following factors can affect an individual's temperature setpoint?
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What physiological response occurs when the body heats up due to external conditions?
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Which condition is characterized by a body temperature that falls below 35°C (95°F)?
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Which physiological variable is not homeostatically regulated?
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What is the primary function of negative feedback in homeostasis?
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What distinguishes positive feedback from negative feedback?
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Which of the following is an example of a positive feedback loop in the human body?
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In the context of heart rate, what is considered the 'effector'?
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Which statement best describes negative feedback?
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Why can heart rate vary widely, from 50 to 195 beats per minute?
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What happens when there is a deviation from the normal range in a homeostatic system?
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Study Notes
Homeostasis and Internal Conditions
- Homeostasis refers to the dynamic stability of the body's internal conditions necessary for cell health.
- Key internal parameters: oxygen levels, pH, nutrient availability, and temperature must remain stable for cellular function and survival.
Setpoints and Variability
- A setpoint is the physiological value around which normal conditions fluctuate, e.g., normal human body temperature is approximately 37°C (98.6°F).
- Setpoints vary among individuals influenced by metabolic rate, body mass, age, and biological sex.
- Acceptable temperature range: 35°C to 38°C; hypothermia occurs below 35°C and fever above 38°C.
Mechanism of Maintaining Homeostasis
- The body continuously monitors internal conditions with temperature sensors, particularly during physical activity.
- During exercise, body temperature may rise, prompting skin sensors to inform a control center (often in the brain).
- The control center communicates with effectors (e.g., sweat glands) to initiate cooling through sweat production.
Regulation of Physiological Variables
- Not all variables are homeostatically regulated; heart rate is an exception, varying widely based on activity level—can be 50 beats per minute at rest and up to 195 beats per minute during exertion.
- The heart acts as an effector to maintain homeostatic levels of blood pressure and oxygenation rather than as a regulated variable.
Feedback Mechanisms
- Negative feedback is the primary mechanism for maintaining homeostasis, reversing deviations from setpoints to stabilize body parameters.
- Positive feedback, contrary to negative feedback, intensifies physiological changes and moves conditions further from the normal range until interrupted, such as in childbirth.
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Description
This quiz explores the fundamental principles of homeostasis in physiology. It delves into the body's internal conditions that must remain stable for the health of our cells, including factors like oxygen levels, pH, and temperature. Test your understanding of how the body maintains dynamic stability despite external changes.
