Homeostasis

Figure 3 shows a diagram of the skin.

Structures in the skin, shown in Figure 3, help to control body temperature.

Explain how the action of the hair erector muscle helps to keep the body warm.

Explain how sweating decreases body temperature.

A scientist investigated the air temperature at which women start to shiver.

The scientist recorded the air temperature at which a 40‑year‑old woman started to shiver.

Which would improve the quality of the results in this investigation?

State the optimum body temperature as shown in Figure 4.

Temperature affects the rate of diffusion of gases into and out of cells.

State two other factors that affect the rate of diffusion.

10 (a) A student wanted to make a jacket to wear in cold weather. The student compared the insulation properties of wool as a natural material with polyester as a synthetic material. Each material was wrapped around a beaker containing hot water as shown in Figure 17. The temperature was recorded every 2 minutes for 12 minutes. thermometer thermometer

Figure 17

(i) Which part of the body controls the regulation of body temperature?

(ii) State one variable that should be controlled in this investigation.

(iii) Describe a control that could be used for this investigation.

(b) The results for this investigation are shown in Figure 18.

(i) Compare and contrast the temperature changes for wool and polyester in this investigation.

(ii) State one improvement to this investigation that would make the results more comparable.

(c) (i) Wearing an insulated jacket may cause a person to sweat. Explain how sweating helps to regulate temperature in humans.

(ii) Sweat contains urea. State where and how urea is produced in the human body.

A student wanted to make a jacket to wear in cold weather.

The student compared the insulation properties of wool as a natural material with polyester as a synthetic material.

Each material was wrapped around a beaker containing hot water as shown in Figure 8.

The temperature was recorded every 2 minutes for 12 minutes.

Which part of the body controls the regulation of body temperature?

State one variable that should be controlled in this investigation.

Describe a control that could be used for this investigation.

The results for this investigation are shown in Figure 9.

Compare and contrast the temperature changes for wool and polyester in this investigation.

State one improvement to this investigation that would make the results more comparable.

Wearing an insulated jacket may cause a person to sweat.

Explain how sweating helps to regulate temperature in humans.

Sweat contains urea.

State where and how urea is produced in the human body.

3 (a) Figure 3 shows a section through the skin.

(Source: © mariyaermolaeva/Shutterstock)

The skin helps to keep body temperature constant.

(i) Which is the correct term for maintaining a constant internal environment?

(ii) Explain how structures X and Y help to regulate body temperature when the body is too cold.

(iii) Explain how shivering can help a person regulate their body temperature.

(b) Figure 4 shows a person’s body temperature during 24 hours. midnight midday midnight

0 2 4 6 8 10 12 14 16 18 20 22 24 time in hours

Figure 4

(i) State this person’s highest body temperature.

(ii) Explain the change in body temperature from 0 hours to 4 hours.

People produce sweat when they are hot.

Sweat consists of substances dissolved in water.

Figure 16 shows the concentration of dissolved substances in the sweat of two patients in a hospital.

Calculate the ratio of the concentration of urea in the sweat of patient A to the concentration of urea in the sweat of patient B.

Give your answer in its simplest form.

Describe how urea is produced in the body.

The blood of patient B has a very high concentration of urea.

Which organ removes most urea from the blood?

The human body can regulate the temperature of the blood.

Which part of the brain controls body temperature?

*(ii) Figure 17 shows a diagram of the skin.

Explain how structures in the skin help to reduce body temperature during hot weather.

Figure 3 shows the positions of the endocrine glands in a woman and a man.

Draw one straight line from each hormone to the effect of the hormone on the body.

How is adrenalin transported from the adrenal glands to its target organs?

What name is given to the process of maintaining the internal body conditions?

Figure 4 shows the concentration of glucose in the blood of a person.

Describe the trends shown in Figure 4 from 0 minutes to 30 minutes.

Explain why the concentration of glucose decreases from 30 minutes to 40 minutes.

A student was investigating the effect of sweating.

The student set up two conical flasks each with a thermometer as shown in Figure 18.

Flask 1 was covered in wet tissue paper.

Flask 2 was covered with dry tissue paper.

Hot water was added to each of the flasks.

The temperature of the water in each flask was recorded every minute for 10 minutes.

State two variables that would need to be controlled in this investigation.

The results of this investigation are shown in Figure 19.

Calculate the rate of temperature change in flask 1 from 1 to 8 minutes.

Compare the trends shown in the data for flask 1 and flask 2.

Explain how sweating helps to cool the body.

Which part of the brain controls internal body temperature?

Explain why it is important to control the internal temperature of the human body.

A student was investigating the effect of sweating.

The student set up two conical flasks each with a thermometer as shown in Figure 5.

Flask 1 was covered in wet tissue paper.

Flask 2 was covered with dry tissue paper.

Hot water was added to each of the flasks.

The temperature of the water in each flask was recorded every minute for 10 minutes.

State two variables that would need to be controlled in this investigation.

The results of this investigation are shown in Figure 6.

Calculate the rate of temperature change in flask 1 from 1 to 8 minutes.

Compare the trends shown in the data for flask 1 and flask 2.

Explain how sweating helps to cool the body.

Which part of the brain controls internal body temperature?

Explain why it is important to control the internal temperature of the human body.