1 (a) Fig. 1.1 shows the human gas exchange system.

m. The functions of the parts of the gas exchange

system are given in Table 1.1.

A
M

K B

C
J

D
H

E
G

Fig. 1.1

Complete Table 1.1. One row has been done for you.

Table 1.1
function letter on Fig. 1.1 name

structure that makes sounds A larynx

bone that provides protection for the lungs E Rib

airway that allows passage of air only into

the right lung J bronchi/ bronchus
airway that allows passage of air into
both lungs
B Trachea/windpipe

contracts to increase volume of thorax F diaphggram

muscle that contracts to lower the ribcage

K internal intercostal muscles
site of gas exchange
M alveoli

[6]

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 (b) The gas exchange system contains cartilage.

Describe the function of cartilage in the gas exchange system.

Flexibility
...........................................................................................................................................

prevent the trachea and bronchi from collpasing when pressure inside
...........................................................................................................................................

...........................................................................................................................................
drops
...........................................................................................................................................

........................................................................................................................................... [2]

(c) Soon after starting physical activity the concentration of carbon dioxide in the blood increases.

(i) Name the process inside cells that produces carbon dioxide.
aerobic respiration
................................................................................................................................

................................................................................................................................ [1]

(ii) State the effect on breathing of an increase in carbon dioxide concentration in the blood.
Increased
................................................................................................................................

................................................................................................................................

................................................................................................................................ [1]

(iii) Explain how this effect on breathing is coordinated.

CO2 diffuses out of the cells into blood plasma .
................................................................................................................................

It is acidic in solution and causes a slight drop in pH of the blood

................................................................................................................................

................................................................................................................................
When blood passes through the brain the aciditiy of it is detected
................................................................................................................................

by chemoreceptors . The brain sends a signal to the diaphgram

................................................................................................................................ and
................................................................................................................................
intercostal mucles to contract more/rapidly to increase rate of
breathing
................................................................................................................................ [3]

[Total: 13]

PhysicsAndMathsTutor.com
2 Fig. 4.1 shows part of the human gas exchange system.

Fig. 4.1

(a) (i) Name structure K.

bronchioles
...................................................................................................................................... [1]

(ii) Ciliated cells and goblet cells line structure L.

Explain the function of these cells in structure L.

Goblet cells produce mucus. Mucus traps pathogens and

...........................................................................................................................................

...........................................................................................................................................
and prevent them from going into the lungs.
...........................................................................................................................................
The cilia moves in a wave like motion to beat and push the
...........................................................................................................................................

...........................................................................................................................................
mucus upwaards away from the lungs
...........................................................................................................................................

...................................................................................................................................... [3]

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 (b) Gas exchange occurs at the alveoli.

(i) Describe how oxygen molecules move from the alveoli into the blood.

...........................................................................................................................................
By diffusion . The concentration of oxygen in the alveoli is greater than
...........................................................................................................................................

that in the blood so it diffuses from a region of higher concentration

........................................................................................................................................... to a
...........................................................................................................................................
region of lower concetration down a concentration gradient across
permeable membrane.
...........................................................................................................................................

...........................................................................................................................................

...................................................................................................................................... [3]

(ii) During inspiration, air moves from the atmosphere into the lungs.

Describe the mechanism of inspiration.

When we inspire , The diaphgram contracts and flattens to increase

...........................................................................................................................................

volume of the thorax. The external intercostal muscle contracts to pull

........................................................................................................................................... the
...........................................................................................................................................
ribs outwards and upwards to increase volume of thorax .
...........................................................................................................................................

The increase in volume means theres a decreaes in pressure. The

...........................................................................................................................................

...........................................................................................................................................
pressure inside the lungs is less than atmoshpheric pressure and air is
pulled in tsts.Internal intercostal muscle is relaxed.
...........................................................................................................................................

...........................................................................................................................................

...................................................................................................................................... [4]

(iii) Name one gas that is found in a higher concentration in expired air than in inspired air.

...................................................................................................................................... [1]

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 (c) Tobacco smoke affects the gas exchange system.

Name two components of tobacco smoke and describe their effect on the gas exchange
system.

component 1 .............................................................................................................................

effect .........................................................................................................................................

...................................................................................................................................................

...................................................................................................................................................

component 2 .............................................................................................................................

effect .........................................................................................................................................

...................................................................................................................................................

...................................................................................................................................................
[4]

[Total: 16]

PhysicsAndMathsTutor.com
 3 The pressure in the lungs of a student before and during the start of a volleyball match was
recorded.

The results are shown in Fig. 2.1.

lung pressure
/ arbitrary units

Fig. 2.1

(a) (i) Use the results in Fig. 2.1 to calculate the breathing rate before the start of the match.
Express your answer to the nearest whole number.

Show your working.

..................................breaths per minute

[2]
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 (ii) Use the results in Fig. 2.1 to describe how the pattern of breathing during the match is
different from the pattern of breathing before the match starts.

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

.......................................................................................................................................[3]

(b) Describe the process of inhalation.

When we inspire , The diaphgram contracts and flattens to increase
...................................................................................................................................................

volume of the thorax. The external intercostal muscle contracts to pull the
...................................................................................................................................................

...................................................................................................................................................
ribs outwards and upwards to increase volume of thorax .
...................................................................................................................................................

The increase in volume means theres a decreaes in pressure. The

...................................................................................................................................................

...................................................................................................................................................
pressure inside the lungs is less than atmoshpheric pressure and air is
pulled in tsts.Internal intercostal muscle is relaxed.
...................................................................................................................................................

...................................................................................................................................................

...............................................................................................................................................[4]

(c) Carbon dioxide is excreted from the body through the lungs.

(i) Explain why this process is termed excretion.

Because carbon dioxide is being removed and CO2 is a toxic substance
...........................................................................................................................................

...........................................................................................................................................

.......................................................................................................................................[1]

(ii) Name the part of the blood in which most carbon dioxide is transported.

.......................................................................................................................................[1]

(iii) Describe the effect of increased carbon dioxide concentration on blood pH.

.......................................................................................................................................[1]

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 (d) Carbon dioxide moves from the blood capillaries into the alveoli by diffusion.

Explain why the rate of diffusion of carbon dioxide increases during exercise.
more aerobic respiration so more cabron dioxide is produced
...................................................................................................................................................

steeper conc gradient

...................................................................................................................................................

...................................................................................................................................................

...................................................................................................................................................

...............................................................................................................................................[2]

[Total: 14]

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4 Fig. 6.1 shows the movement of the ribs and the diaphragm during breathing in.

external
intercostal
muscles
vertebrae

sternum

diaphragm

Fig. 6.1

(a) State what happens to the following structures during breathing in.
contracts and flattens
diaphragm ..................................................................................................................................

...................................................................................................................................................

...................................................................................................................................................
moved upwards and outwards
ribcage .......................................................................................................................................

...................................................................................................................................................

...................................................................................................................................................
contracts to pull ribs out and u[
external intercostal muscles ......................................................................................................

...................................................................................................................................................

...............................................................................................................................................[3]

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(b) Explain the effect of strenuous physical activity on the pH of the blood.

we respire more during strenous activity and CO2 is a product of aerobic

...................................................................................................................................................

...................................................................................................................................................
respiratoin . CO2 moves out of the cells into blood plasma and it lowers the
pH there,
...................................................................................................................................................

forms carbonic acid.

...................................................................................................................................................

...................................................................................................................................................
also anaerobic respiration happens during strenous exercise and lactic acid
...................................................................................................................................................
is forme which lowers pH of blood
...................................................................................................................................................

...............................................................................................................................................[3]

[Total: 6]

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