1.1 HUMAN BREATHING MECHANISM

Parts FunctionRib cage Protects the lungsNasal cavity To warm, moisten and filter fine particles like dustIntercostal muscle Raises and lowers the rib cage during breathingDiaphragm Changes the air pressure in the thoracic cavity by

increasing and decreasing the thoracic volume.Alveolus The place where the exchange of gases takes place

1. Breathing is a process during which our body: a) Takes in of oxygen – INHALATION b) Lets out of carbon dioxide – EXHALATION

2. Pathway of inhaled

ACTIVITY

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1.

Nose Trachea Bronchus Bronchiole Alveolus

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RESPIRATION

Involves

ProcessesHuman

respiratory system Inhale Exhale

Consists of

Breathing organs

- Ribs- Diaphragm- Intercostal

musclesNasal cavity

Trachea

Bronchuss

Bronchiole

Alveolus

Situated in the lungs

CO2O2

Air taken in

Air taken out

Caused by

Change in pressure

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Concept Map

OBJECTIVE QUESTIONS

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1 Figure 1 below shows a cross- section of the

human respiratory system.

Figure 1

Which of the following represents P, Q, R and

S?P Q R S

A Trachea Alveolus Bronchus Bronchiole

B Trachea Bronchus Alveolus Bronchiole

C Bronchus Alveolus Bronchiole Trachea

D Alveolus Trachea Bronchus Bronchiole

2

W - Alveolus

X - Bronchiole

Y - Bronchus

Z - Trachea

Table 1

The table shows the various parts of the human

respiratory system.

Which is the correct sequence for the flow of

oxygen from the air to the lungs ?

A. W X Y Z

B. W Y X Z

C. Z X Y W

D. Z Y X W

3 One of the waste products of respiration is

A. Carbon dioxide

B. Carbon monoxide

C. Nitrogen dioxide

D. Nitrogen oxide

- Thoracic cavity becomes bigger- Air pressure inside the lungs is lowered- Air is forced into the lungs

4 The information above shows the process

of…..

A digestion

B inhalation

C exhalation

D respiration

Figure 2

5 In Figure 2, which part is the trachea?

A

B

C

D

Figure 3

6. Which of the following, represents the lung ?A P C RB Q D S

7. What happens to the diaphragm during inhalation?

A It curves and moves upwardsB It relaxes and moves upwardsC It contracts and moves downwardsD It curves and moves downwards

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Figure 4

Figure 4 shows a model of the human respiratory system. Which of the following statements is not true when the rubber sheet is pulled downwards?A Pressure in the bell jar decreases.B Both balloons expand.C Air enters into the balloons.D Both balloons expand until they

burst.

9 Which of the following organs is not involved in the respiratory system?

A LungsB RibsC DiaphragmD Heart

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Figure 5

What takes place in the structure labelled S?A Exchange of gases for breathing

B Secretion of enzymes for food digestion C Production of oxygen for respiration D Production of new cells to replace dead

cells

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Air is exhaled out of the lungs in this sequenceA K, L, M, NB N, M, K, LC M, K, L, ND N, L, K, M

12 In the breathing mechanism, which action reduces the volume of the thoracic cavity? A The outer intercostal muscles contract.B The inner intercostal muscles contract.

C The diaphragm muscle contracts. D The outer rib cage moves upwards and

forwards.

Stopper

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Rubber sheet

P

Q

R

S

13 Which of the following releases water vapour into the air?I RespirationII TranspirationIII Photosynthesis

A I and II onlyB I and III onlyC II and III onlyD I, II and III

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Figure 6Figure 6 shows a simple model of the thoracic cavity. Which of the following occurs when the diaphragm curves upwards?A Outer intercostal muscles contract. B Air from the atmosphere is inhaled

into the lungs.C Diaphragm muscle contracts. D Air pressure in the thoracic cavity is

higher than the atmospheric pressure.

15 Which of the following occurs when the outer intercostal muscles contract?I The ribs move upwards.II Inner intercostal muscles contract.III Diaphragm muscle contracts.IV Volume of the thoracic cavity decreases.

A I and II onlyB I and III onlyC II and IV onlyD I, III and IV only

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Figure 7

Figure 7 shows the breathing mechanism. At which of the points, A, B, C or D is the air pressure lowest?

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Figure 8Figure 8 shows the air passage from the nose to structure X. What are the characteristics of structure X?I Moist surfaceII Thin-walledIII Surrounded by a network of blood capillaries

A I and II onlyB I and III onlyC II and III onlyD I, II and III

18 Which of the following correctly shows the contents of inhaled air and exhaled air?

Gas Inhaled air Exhaled air

IOxygen 21 % 16 %

II Carbon dioxide

0.03 % 4 %

III Nitrogen 78 % 78 %IV Water

vapourA little 50 %

A I and II onlyB III and IV only C II, III and IV onlyD I, II, III and IV

STRUCTURE QUESTIONS

1. Diagram 1 shows a part of the respiratory system.

(a) Name the structures labelled P, Q and R

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A sheet of muscles which separates the thorax from the abdomen

Tube supported by rings of cartilage

Space where air passes through

Bones that form the rib cage to protect the lungs

Diagram 1

Trachea Rib Diaphragm

(b) Draw lines to show the correct match between the structures and their description.

2. Diagram 2 below shows the process of inhalation in the human breathing mechanism.

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P

R

Q

Diagram 2

(a) Following the path of the air in the diagram 2, state what happens to the following parts during inhalation.

(i) External intercostal muscles:

(ii) Ribs:

(iii) Diaphragm:

(iv) Thoracic cavity:

(v) Lungs:

(b) Name three types of gases inhaled in during the process of inhalation.

3

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Figure 1Figure 1 shows the human respiratory system.

(a) Name the structures X, Y and Z.

(i) X : _____________________________________________________

(ii) Y : ____________________________________________________

(iii) Z : _____________________________________________________

(b) Name the gas that diffuses through the alveolus into the capillaries.

_____________________________________________________

(c) What takes place at Z?

_____________________________________________________

(d) Complete the flow chart below to show the sequence of air movement from the nose to the alveolus.

1.2 TRANSPORT OF OXYGEN IN THE HUMAN

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1. Oxygen in the inhaled air that is taken into the alveolus in the lungs will diffuse into the blood capillaries.

2. The alveolus is efficient in gaseous exchange because:a) it has a one-cell thickb) it has moist (this helps gas to dissolve)c) it is surrounded by a large network of blood

capillariesd) it has millions of alveoli to increase its surface area.

3. In the blood oxygen will combine with the haemoglobin in the red blood cells to form oxyhaemoglobin.

4. When oxyhaemoglobin reaches the body tissues, it decomposes to release oxygen. The oxygen then diffuses into the cells. In the body cells, the oxygen is used for respiration.

5. Respiration is a food oxidation process in the body cells to release energy, carbon dioxide and water.

Oxyhaemoglobin

Decomposes

Oxygen

Diffuses into the cells

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Deoxygenated blood

Oxygenated blood

Oxygen+

haemoglobin

Oxyhaemoglobin

Glucose + oxygen carbon + water + energy dioxide

OBJECTIVE QUESTIONS

Oxygen

NASAL CAVITY

ALVEOLUS

Diffusion

Red blood cell

Combines with oxygen

Breaks down into

Products of digestion

BODY CELL

A type of process

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ACTIVITY

\

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1 Alveolus is suitable for diffusion of gases because it has

I thin wallsII dry surface areaIII large number of blood capillaries IV small surface area

A I and II B I and III C II and III D II and IV

2 Figure 1 below shows the exchange of gases between an alveolus and a blood capillary.

Figure 1

The exchange of gases between the alveolus and the blood capillary is by

A diffusionB transfusionC convectionD conduction

3 Which of the following statements is true about the oxidation of food that takes place in cells?I This process is called respiration.II Energy is absorbed.III Water vapour is released in this process.

A I and II onlyB I and III onlyC II and III onlyD I, II and III

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Figure 2

Figure 2 shows the alveolus and the blood vessels around it. Haemoglobin is transported from blood vessel X to blood vessel Y. Which of the following pairs represents blood vessels X and Y?

X YA Pulmonary vein Pulmonary arteryB Pulmonary artery Pulmonary veinC Vena cava AortaD Aorta Vena cava

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Figure 3

Which of the following represents gases X and Y?

X YA Carbon dioxide OxygenB Oxygen Carbon dioxideC Hydrogen OxygenD Oxygen Hydrogen

6 Cell respiration can be represented by the following word equation:

Glucose + J K + water + carbon dioxide

What do J and K represent?

J KA Oxygen FoodB Oxygen EnergyC Haemoglobin Amino acids D Ribosomes Energy

7 How does oxygen in the alveolus enter the blood?

A By osmosisB By reverse osmosisC By diffusionD By transpiration

8 Which of the following characteristics help the alveolus absorb oxygen more

efficiently?

I the alveolus is always dry II the alveolus has a large surface area III the alveolus has thin walls

IV blood capillaries that carry oxygen surround the alveolus

A. I, II, and III onlyB. I, III, and IV onlyC. II, III, and IV onlyD. I, II, III, IV

9 How is oxygen from the lungs transported to every cell in our body?

A. It is transported in the form of oxyhaemoglobin in red blood cells.

B. It is transported in the form of carboxyhaemoglobin.

C. It is transported by the white blood cells.

D. It is transported in the plasma.

10 The oxidation of food in a cell during cell respiration as shown in the diagram below

will produce a gas.

The gas can

A. turn lime water chalky.B. ignite a glowing splinter.C. be used for respiration.D. support combustion.

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Gas Y that enters the blood stream from the alveolus is used by cells as shown above in the process of

A. assilimation. B. digestion. C. respiration. D. breathing.

12 The breathing process is important in order to I lower the water vapour content in the

alveoli. II increase the amount of oxygen in the

alveoli. III lower the concentration of carbon

dioxide in the alveoli.

A.. I and II only B. I and III only C. II and III only D. I, II and III

STRUCTURE QUESTIONS

13

1

( a ) Name the parts labeled P, Q, and R using the following terms

( b) Draw a line to show the correct match between the structure and their descriptions

Structure Description

2

Alveolus bronchiole capillary

P

Q

Small branches inside the lungs . At the end of these tubes are the alveoli

Tube that leads into the lungs and divides into smaller tube

The structure are sounded by tiny blood vessels

The smallest blood vessel in our bodyR

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Figure 2

Figure 2 shows an air sac surrounded by blood capillaries in the lung.

(a) What is the difference between the blood in blood vessels X and Y?

__________________________________________________________

(c) What is the name of the air sac in the lung?

(d) State three characteristics of the air sac which can increase the efficiency of gas diffusion.

(i) ___________________________________________________

(ii) ___________________________________________________

(iii)

(e) What happens to the oxygen that diffuses into the blood in the blood capillaries?

__________________________________________________________

__________________________________________________________

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15

Figure 3(a) Based on figure 15, state

(i) Gas P : _________________________________________________________

(ii) Gas Q : ________________________________________________________

(b) Which blood is(i) oxygenated blood?

________________________________________________

(ii) deoxygenated blood? ___________________________________

(c) State the process which causes the exchange of gases on the surface of an alveolus.______________________________________________________________

(d) Why does the wall of an alveolus allow gases to be exchanged rapidly?

______________________________________________________________

1.3 IMPORTANCE OF A HEALTHY RESPIRATION SYSTEM

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TThe substances which are harmful to the respiratory system

ACTIVITY

Complete the flow chart below

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SOURCE

Cigarette smokeTar

Causes lung cancer

Carcinogens

Carbon monoxxide

Nicotine

Irritants

Causes various types

of cancer

Causes addiction

Cough and lung cancer

Causes a lack of O2 in our body

Vehicle Factory smoke

Benzo-alpha-pirena

Fine dust

Tiny solid particles

Sulphur dioxide

Bronchitis

Lung cancer

Coughs

Breathing difficulties

Lead

Carbon monoxide

Air pollutants

Such as

CONCEPT MAP

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Cigarette smoke1……………….

Tiny solid particles (haze) 2………………

.

3. Sticky brown substance

4..Chemicals which irritate the air passages and alveoli in the lungs

Nicotine Harmful 5…………………………. Which causes addiction

6. Cancer causing chemicals

Nicotine Colourless, odourless and poisonous gas which prevents 7……………………….. from transporting 8……………………………. Around the body

Causes diseases such as

OBJECTIVE QUESTIONS

Breathing

involves

Inhalation Exhalation

of

Air

Which contains

Harmful substances

such as

Nicotine, tar, sulphur dioxide, tiny solid particles, carbon monoxide, toxins and carcinogens

that cause

Diseases that affect the respiratory system

such as

Asthma, bronchitis, emphysema and lung cancer

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4

7

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1. Figure 1 below shows an experiment to investigate the effects of smoking on the lungs

Figure 1What are represented by Q, R and S?

Q R SA Filter pump Cotton wool Universal

indicatorB Condenser Cotton wool Universal

indicatorC Filter pump Cotton wool Sulfuric acidD Filter pump Manila

paper Universal indicator

2 Which of the following pollutants and their effects is correctly matched?

Pollutant EffectA Haze Causes cancerB Tar Reduces the acidity of the lungsC Carbon dioxide Increases cell activityD Sulphur dioxide Damages lung tissue

3 Which of the following activities causes haze?

A Generating hydroelectricityB Excessive spraying of chemical

pesticidesC Barbecuing food D Burning of agricultural waste

4 The following diseases are caused by smoking except

A heart diseaseB lung cancerC tuberculosis

D bronchitis

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Figure 2 Figure 2 shows an experiment to study

the effects of smoking on the lungs. What can be observed at the end of the experiment?I The moist white cotton turns

yellowish brown.II The colour of the bicarbonate

indicator turns from red to yellow.III The thermometer records a rise in

temperature.

A I and II onlyB I and III onlyC II and III onlyD I, II and III

6 The carbon monoxide in the smoke that is released from the exhaust of vehicles can

A. block oxygen supply to parts of the body.B. trigger the growth of cancer cells.C. destroy the walls of the trachea.D. stick to the lungs.

Table 1

Table 1 shows the substances in cigarette smoke and their respective adverse effects. Which of the following represents substances X, Y and Z?

X Y ZA Nicotine Tobacco tar Acidic gasB Tobacco tar Nicotine Carcinogenic substancesC Carcinogenic substances Acidic gas Tobacco tarD Acidic gas Carcinogenic Nicotine

substances

STRUCTURE QUESTIONS

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8 Carbon monoxide harms the respiratory system by

A. stimulating the growth of cancer cells.B. killing the red blood cells along the

trachea wall.C. sticking to the heart and the walls of air

passages.D. combining with haemoglobin and

slowing down oxygen transport

9 Which of the following pollutant in cigarettes is correctly matched to its harmful

effect?

Pollutant Harmful effectA Tar BronchitisB Nicotine Hardens blood

vesselsC Carcinogens EmphysemaD Carbon monoxide Smoker’s cough

10 What is the substance in cigarette smoke that causes addiction?

A TarB NicotineC Carbon monoxideD Sulphur dioxide

11 Why are cigarette smokers sometimes short of breath?

A Their lung tissue has turned blackB Cigarette smoke reduces the amount

of oxygen in the bloodC Their lung tissue contains nicotineD There are many poisonous gases in

their lymphatic system

12 Which of the following diseases is caused by smoking cigarettes?

I Lung cancerII EmphysemaIII BronchitisIV Hepatitis

A I and II onlyB III and IV only C I, II and III onlyD I, II, III and IV

1. Figure 1 below shows the model of the human respiratory system.

Figure 1

a) When the cigarette is lighted, state your observations on the following.

i) The temperature :

___________________________________________________________

ii) The white cotton wool :

___________________________________________________________

iii) The hydrogen carbonate indicator

___________________________________________________________

b) State three good habits that can help to improve the quality of air. i)_____________________________________________________________

ii)____________________________________________________________

iii)____________________________________________________________

c) Name two diseases that affect the human respiratory system.

i) _______________________________________________

ii) _______________________________________________

ANSWERS

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1.1Activity (Page 1 )

1. A (Nasal Cavity)2. B (Lungs)3. Down4. E (Bronchus)5. C (Bronchiole)6. F (Ribs)

ACTIVITY (Page 2)

Breathing is controlled by muscle

Contracts and move dowanwards and flattens // Espands and curves upwards Increases // DecreasesDecreases // IncreasesContracts // RelaxesRelaxes // ContractsUpwards and outwards // Downwards and inwardsAir enters into the lungs // Air flows out

OBJECTIVE QUESTIONS (Page 4)1. A2. D3. A4. B5. B6. C7. C8. D9. D10. A11. C12. A13. A14. D15. D16. C17. D18. D

STRUCTURE QUESTIONS (page 7-9)1. a) P; Trachea

Q; RibR: Diaphragm

b) Q: Bones that form the rib cage to protect the lungsR: A sheet of muscles which separates the thorax from abdomen

2. ai) Contracts ii) Upwards and outwards

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iii) Contracts and move dowanwards and flattens iv) Increasesv)

b) Oxygen, carbon dioxide and nitrogen

3. (a) (i) X: Trachea(ii) Y: Bronchus(iii) Z: Bronchiole

(b) Oxygen(c) Exchange of gases in breathing(d)

1.2Activity (Page 11 )Trachea – BronBronchus – Bronchiole – Haemoglobin –Oxyheamoglobin – Oxygen

Glusoce EnergyCell respiration Carbon dioxide

Water

OBJECTIVE QUESTIONS (Page 12-13)1. B2. A3. B4. B5. A6. B7. C8. C9. A10. A11. C12. D

STRUCTURE QUESTIONS (page 14 -16)1.a) P: Capillary Q: Bronchiole R: Alveolusb) Q: Small branches inside the lungs. At the end of these tubes are the alveoli. R: The structure are srounded by tiny blood vessels.2) (a) Blood vessel X carries deoxygenated blood while blood vessel Y carries

oxygenated blood(b)

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(c) Alveolus(d) (i) Has thin wall

(ii) Moist surface(iii) Plenty of blood capillary networks

(e) Oxygen combines with haemoglobin in the red blood cells to form oxyhaemoglobin.

3 a) gas P – oxygen, gas Q – carbon dioxide

b) i) Y ii) X

c) diffusion

d) walls of the alveoli are one-cell thick, have a large surface area

1.3

Activity (Page 18 )1. Sulphur dioxide2. Toxins3. Tar4. Irritents5. Substance6. Carcinogens7. Haemoglobin8. Oxygen9. Asthma10. Emphysema11. Bronchitis12. Lung Cancer13. Poenumonia

OBJECTIVE QUESTIONS (Page 4)1. A2. D3. D4. C5. D6. A7. A8. D9. B10. B11. B12. C

STRUCTURE QUESTIONS (page 22)

1. a) i. The temperature raiseii. The colour of white cotton wool turns from white to brownish yellow

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iii. The hydrogen carbonate turns from red to yellow

b) i) Abstain from smoking ii) Car pool iii) Minimise air conditioning use iv) Keep carpet and floor dust free

v) Maintain a low humidity to prevent mould growth

(c) i) Asthma ii) Bronchitis iii) Lung cancer iv) Emphysema v) Pneumonia

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