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
8
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
5
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
21
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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