When a person is submerged in cold water, their body temperature can drop very quickly. This is because heat is transferred quickly, by conduction, from the warm body into the cold water. An experiment was carried out to see if it is better to stay still if you fall into cold water or try to swim. Two men sat for 30 minutes, in the air at a temperature of 15 o C. They then got into the swimming pool, where the water was also at a temperature of 15 o c, Person A swam for the next 30 minutes. Person B lay still in the water. The body temperature of both men was measured at 10-minute intervals throughout the experiment. The results are shown in the graph. Explain why their body temperature remained roughly constant for the first 30 minutes of the experiment.

Humans are endothermal organisms and can maintain the homeostasis of their body. The human body is capable of maintaining a constant internal body temperature at about 37 0 C of the body even if the outer environment temperature becomes too cold or too hot. The body temperature of both the described men in the experiment remained roughly constant for the first 30 minutes of the experiment the reason being the body's ability of homeostasis. Body temperature is regulated by the hypothalamus that acts as the temperature controlling centre. When in cold water, the metabolism of the body increases and also vasoconstriction of the blood vessels of the skin occurs which results in an increase in the body's internal temperature. Due to which the body temperature remains constant.

When a person is submerged in cold water, their body temperature can drop very quickly. This is because heat is transferred quickly, by conduction, from the warm body into the cold water. An experiment was carried out to see if it is better to stay still if you fall into cold water or try to swim. Two men sat for 30 minutes, in the air at a temperature of 15 0 C. They then got into the swimming pool, where the water was also at a temperature of 15 0 c, Person A swam for the next 30 minutes. Person B lay still in the water. The body temperature of both men was measured at 10-minute intervals throughout the experiment. The results are shown in the graph. Suggest why person A's temperature dropped faster than the person B's temperature during this time period.

The body temperature of both the described men in the experiment remained roughly constant for the first 30 minutes of the experiment the reason being the body's ability of homeostasis. Body temperature is regulated by the hypothalamus that acts as the temperature controlling centre. When in cold water, the metabolism of the body increases and also vasoconstriction of the blood vessels of the skin occurs which results in an increase in the body's internal temperature. Due to which the body temperature remains constant. However, a constant need of the body for a temperature rise demands energy that is provided by the stored food in the body and by the activity of muscles that contracts to increase the production of heat. Since man A kept on swimming for 30 minutes while man B was laying still. Thus, the energy consumed by the swimming man is more as compared to the other so the person A's temperature dropped faster than the person B's temperature due to his increased physical activity.

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Upper Secondary: IGCSE

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Outline two advantages and one disadvantage of maintaining constant internal body temperature.

Important Questions on Homeostasis

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Upper Secondary: IGCSE

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Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 14 - Homeostasis>Questions>Q 14.1

Outline two advantages and one disadvantage of maintaining constant internal body temperature.

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Upper Secondary: IGCSE

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Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 14 - Homeostasis>Questions>Q 14.2

Give two functions of the fatty tissue beneath the skin.

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Upper Secondary: IGCSE

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Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 14 - Homeostasis>Questions>Q 14.3

Explain how sweating helps to cool the body.

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Upper Secondary: IGCSE

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Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 14 - Homeostasis>Questions>Q 14.4

Name the organ which coordinates temperature regulation.

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Upper Secondary: IGCSE

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Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 14 - Homeostasis>Questions>Q 14.5

Explain what vasodilation is, and how it helps to cool the body.

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Upper Secondary: IGCSE

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Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 14 - Homeostasis>End-of-chapter questions>Q 2

The following sentence contains incorrect information. Identify what is wrong and write the correct sentence.
Insulin is an enzyme that changes glucose to glycogen.

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Upper Secondary: IGCSE

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Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 14 - Homeostasis>End-of-chapter questions>Q 3

When a person is submerged in cold water, their body temperature can drop very quickly.

This is because heat is transferred quickly, by conduction, from the warm body into the cold water. An experiment was carried out to see if it is better to stay still if you fall into cold water or try to swim.

Two men sat for 30 minutes, in the air at a temperature of 15^oC.
They then got into the swimming pool, where the water was also at a temperature of 15^oc,
Person A swam for the next 30 minutes. Person B lay still in the water.

The body temperature of both men was measured at 10-minute intervals throughout the experiment. The results are shown in the graph.

Question Image

Explain why their body temperature remained roughly constant for the first 30 minutes of the experiment.

HARD

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Biology Coursebook Third Edition>Chapter 14 - Homeostasis>End-of-chapter questions>Q 3

When a person is submerged in cold water, their body temperature can drop very quickly.

Two men sat for 30 minutes, in the air at a temperature of 15⁰C.
They then got into the swimming pool, where the water was also at a temperature of 15⁰c,
Person A swam for the next 30 minutes. Person B lay still in the water.

The body temperature of both men was measured at 10-minute intervals throughout the experiment. The results are shown in the graph.

Question Image

Suggest why person A's temperature dropped faster than the person B's temperature during this time period.

Outline two advantages and one disadvantage of maintaining constant internal body temperature.

Important Questions on Homeostasis

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