Biology - Unit 1 - Chapter 4 - Lungs and Lung Disease
How should tuberculosis be prevented? (3)
By a vaccination containing a weakened strain of mycobacterium bovis; Better education about TB; Better nutrition to ensure good immune systems
Give one other way that helps to maintain the difference in oxygen concentration. (1)
Circulation of blood
People suffering from emphysema have less elastic tissue in their lungs. Explain how this affects the efficiency of gas exchange in the alveoli. (3)
Inability to recoil and stretch; Decreased concentration gradient; So less oxygen enters the alveoli and less CO2 leaves the alveoli
Suggest two reasons for the increase in asthma sufferers. (2)
Increase in air pollution; Increase in stress
(Refer to exam q) The drawing shows some of the structures involved in ventilating human lungs. Name structure A. (1)
Intercostal muscle
Describe the role of structure A in inspiration. (3)
It contracts; Pulling ribs upwards and outwards; Increasing volume of thorax
Explain why the presence of these large air spaces reduces gas exchange. (2)
Less contact with capillaries; So less oxygen into the blood
A person with emphysema found it difficult to carry out exercise. Explain why. (3)
Less oxygen reaches the muscles; Oxygen is needed for aerobic respiration; Less energy is released for exercise
What are the problems associated with drugs to control tuberculosis? (2)
Long time period so people may stop taking it; Resistant strains of the bacteria
(Refer to June 2010 paper) The graph shows changes in the volume of air in a person's lungs during breathing. The person was breathing in between times A and B on the graph. Explain how the graph shows that the person was breathing in between times A and B. (1)
Lung volume increases
Explain how ventilation increases the rate of gas exchange in the alveoli. (2)
Maintains a greater diffusion gradient; to allow faster diffusion
Person B has emphysema. Give one piece of evidence from the table that shows this. (1)
More air left in lungs after breathing out
(Refer to Jan 2010 paper) Scientists investigated the number of cases of miner's lung reported in Britain between 1992 and 2006. Coal mining in Britain had been dramatically reduced by 1990.Some scientists concluded that the rise in reported cases of miner's lung after 1992 shows that the disease takes a long time to develop. Evaluate this conclusion. (2)
No because Correlation does not prove causation - there may be other factors influencing miner's lung; Not all individuals with miner's lung were reported
What is pulmonary tuberculosis caused by? (1)
One of two species of rod-shaped bacteria: mycobacterium tuberculosis or mycobacterium bovis
What are the symptoms of pulmonary tuberculosis? (4)
Persistent cough; Tiredness; Weight loss; Fever
Complete the equation. Pulmonary ventilation = ....................× .................. (1)
Pulmonary ventilation = Tidal volume x Ventilation rate
The person's pulmonary ventilation changed between times C and D. Describe how the graph shows that the pulmonary ventilation changed. (3)
Pulmonary ventilation = tidal volume × breathing rate; Breathing rate increases between C and D; Tidal volume increases between C and D
Explain how a person breathes out. (4)
Relaxation of intercostal muscles moves ribs down and in; Relaxation of diaphragm muscles causes it to return to its dome shape; There is a decrease in volume of thorax and increase in pressure of air; Air moves out down pressure gradient
Why do alveoli contain elastic fibres? (2)
So that they can stretch as they fill with air when breathing in; and can recoil during breathing out to expel the CO2-rich air
Scientists who investigate disease may look at risk factors. What is a risk factor? (1)
Something that increases chance
How is pulmonary tuberculosis transmitted? (3)
The bacteria is transmitted through the air by droplets released when infected people cough, sneeze, talk etc and inhaled; Takes close contact with an infected person over a period of time rather than a short encounter; Also transmitted through milk
What is the site of gas exchange in mammals? (1)
The epithelium of the alveoli
What is pulmonary ventilation? (1)
The total volume of air that is moved into the lungs during one minute
Describe two adaptations of the structure of alveoli for efficient gas exchange. (2)
Thin walls; Total surface area is large
Who are at greater risk of contracting pulmonary tuberculosis? (4)
Those in close contact with infected individuals over long time periods; Long-term care facilities e.g. hospitals, care homes, prisons; Those with reduced immunity; The very young and very old
How do you calculate pulmonary ventilation? (1)
Tidal volume x Ventilation rate
Why does the trachea have rings of cartilage around it? (1)
To support it and prevent it collapsing as the air pressure inside falls when breathing in
Micrographs of lung tissue taken from people with emphysema show large air spaces compared with lung tissue from healthy people. Explain why. (1)
Walls of alveoli break down
How is diffusion calculated? (1)
surface area x difference in concentration ------------------------------------------------------ length of diffusion pathway
Asthma reduces the efficiency of gas exchange in the lungs. Explain why. (4)
Allergens cause white blood cells on the linings of the bronchi to release a chemical called histamine; this causes the epithelial cells to secrete larger quantities of mucus; and causes the bronchiole muscles to contract and so constricts, reducing flow of air; So it is more difficult to ventilate the lungs and the diffusion gradient is reduced
What is the cause of asthma? (2)
Allergens; such as pollen, animal fur, air pollutants etc
Pulmonary tuberculosis is a disease of the lungs. Describe the transmission and course of infection of pulmonary tuberculosis. (5)
Bacteria transmitted in droplets; Bacteria destroy epithelial cells of the alveoli; Which leads to scar tissue; This damage increases diffusion distance so less diffusion; Activation allows bacteria to enter blood and spread to other organs
(Refer to Jan 2012 paper) Scientists investigated the link between pollution from vehicle exhausts and the number of cases of asthma. Between 1976 and 1996, the scientists recorded changes in the following - the concentration in the air of substances from vehicle exhausts - the number of cases of asthma. The graph shows their results. Between which years on the graph was there a positive correlation between the number of cases of asthma and the concentration in the air of substances from vehicle exhausts (1)
Between 1976 and 1980
Between which years on the graph was there a negative correlation between the number of cases of asthma and the concentration in the air of substances from vehicle exhausts? (1)
Between 1980 and 1996
Describe how air is taken into the lungs. (3)
Contraction of diaphragm muscles flattens diaphragm; Contraction of intercostal muscles raises ribcage; Increase in volume of thorax decreases pressure of air
Explain how a person breathes in. (4)
Contraction of intercostal muscles pulls ribs up and out; Contraction of diaphragm muscles causes it to flatten; There is an increase in volume of thorax and decrease in pressure of air; Air moves in down pressure gradient
Calculate the rate at which person A breathed air out of his lungs between 0 and 3 seconds. Show your working. (0 = 6.5, 3 = 2.3) (2)
Correct answer 1.4; vol. air breathed out = 6.5 - 2.3 / 4.2 dm3
The scientists concluded that substances in the air from vehicle exhausts did not cause the increase in asthma between 1976 and 1980. Explain why. (3)
Correlation does not mean that there is a causal relationship; May be some other factor infuencing the increase in asthma cases; After 1980 asthma continues to rise but exhaust concentration falls
(Refer to June 2006 paper) Emphysema is a disease that affects the alveoli of the lungs and leads to the loss of elastic tissue. The photographs show sections through alveoli of healthy lung tissue and lung tissue from a person with emphysema. Both photographs are at the same magnification. Using the evidence given above and your own knowledge, explain why a person with emphysema is unable to do vigorous exercise. (4)
Decreased surface area of alveoli; so less diffusion of gases; Therefore not enough O2; for increased respiration during exercise
(Refer to Jan 2012 paper) A person with asthma breathed out as hard as he could. The graph shows the volume of air he breathed out in the first 6 seconds of a breath. Curve A shows the volume before he used an inhaler. Curve B shows the volume after he used an inhaler. The diaphragm helps to bring about the changes shown by the curve A. Explain how. (3)
Diaphragm relaxes; Diaphragm moves up into a domed shape; Which decreases the volume of the thorax
Describe and explain the symptoms of asthma. (4)
Difficulty in breathing; due to the constriction of the bronchioles and the addition of mucus within them; Tightness in chest; due to not being able to ventilate the lungs properly
Name the process by which oxygen passes from an alveolus in the lungs into the blood. (1)
Diffusion
Describe how oxygen in air in the alveoli enters the blood in capillaries. (2)
Diffusion; Across alveoli epithelium
Emphysema reduces the efficiency of gas exchange in the lungs. Explain why. (4)
Epithelium walls thicken; And there is less elastic tissue in lungs; So less air expelled; Which results in a reduced concentration gradient
You could use curve A to find the total volume of air that this person could breathe out in one complete breath. Describe how. (2)
Extend graph; Read off where it flattens
The photograph shows a fire-breather creating a ball of fire. Fire-breathers do this by blowing a fine mist of paraffin oil onto a flame. Some of this mist can be inhaled and may eventually lead to fibrosis. People who have been fire-breathers for many years often find they cannot breathe out properly. Explain why. (2)
Fibrosis reduces elasticity of alveoli; Due to scar tissue
Describe and explain what happens to the shape of the diaphragm between times A and B. (2)
Flattens; As diaphragm contracts
(Refer to June 2012 paper) The diagram shows the position of the diaphragm at times P and Q. (P = person resting, Q = person inhaling) Describe what happens to the diaphragm between times P and Q to bring about the change in its shape. (2)
Flattens; Diaphragm muscle contracts
Explain how downward movement of the diaphragm leads to air entering the lungs. (2)
Increases volume in the thorax; Lowers pressure in the thorax
Air moves into the lungs between times P and Q. Explain how the diaphragm causes this. (3)
Increases volume of the thorax; Decrease in pressure; Air moves from high to lower pressure
Pulmonary fibrosis reduces the efficiency of gas exchange in the lungs. Explain why. (4)
It arises when scars form on the epithelium of the alveoli, causing them to become irreversibly thickened; So oxygen cannot diffuse into the blood as quickly because the diffusion pathway has been lengthened; Fibrosis also reduces elasticity of alveoli; So less air is expelled and lungs are not properly ventilated, reducing the concentration gradient
Emphysema is another disease of the lungs. People with emphysema may feel weak and tired. Explain why. (5)
Loss of elastic tissue in the lungs; Alveoli cannot recoil and it becomes more difficult to expel air; Which results in a reduced diffusion gradient; So less oxygen enters blood; Which results in less respiration
Describe and explain how the lungs are adapted to allow rapid exchange of oxygen between air in the alveoli and blood in the capillaries around them. (5)
Many alveoli and capillaries which provide a large surface area; So fast diffusion; Flattened epithelium of alveoli and capillaries; So short diffusion pathway; Circulation and breathing movements; Maintains a concentration gradient
(Refer to June 2006 paper) Emphysema is a disease that affects the alveoli of the lungs and leads to the loss of elastic tissue. The photographs show sections through alveoli of healthy lung tissue and lung tissue from a person with emphysema. Both photographs are at the same magnification. Using the evidence given above and your own knowledge, explain why a person with emphysema is unable to do vigorous exercise. (4)
Not enough O2; For increased respiration; Because there is decreased surface area of alveoli; So less diffusion of oxygen into the blood
Describe and explain the symptoms of emphysema. (4)
Shortness of breath; due to difficulty in exhaling air due to loss of elasticity in alveoli; which reduces diffusion gradient and decreases the rate of diffusion of oxygen into the blood; also due to smaller alveolar surface area which reduces diffusion of oxygen into the blood
Why are the bacteria in the tuberculosis vaccine weakened before they are injected? (1)
So they are less likely to cause the symptoms of tuberculosis
Suggest two reasons for the recent increase in tuberculosis in developed countries. (2)
The development of resistant strains of the bacteria; Increase in HIV
Explain how the cells lining the trachea and bronchus protect the alveoli from damage. (3)
The goblet cells produce mucus that traps dirt particles and bacteria in air breathed in; The cilia move this mucus up the trachea and into the stomach; The dirt and bacteria could cause infection in the alveoli
Why are bronchioles made of muscle? (2)
The muscle contracts which allows bronchioles to constrict; to control the flow of air in and out of the alveoli
What is ventilation rate? (1)
The number of breaths taken in one minute
What is tidal volume? (1)
The volume of air normally taken in at each breath when the body is at rest
Why is the volume of oxygen that has to be absorbed and the volume of CO2 that has to be removed large in mammals? (2)
They are relatively large organisms with a large volume of living cells; They maintain a high body temperature and therefore have high respiratory rates
Explain why people with miner's lung have a lower concentration of oxygen in their blood. (1)
Thicker alveolar wall so longer diffusion pathway
Miner's lung is a disease caused by breathing in dust in coal mines. The dust causes the alveolar epithelium to become thicker. People with miner's lung have a lower concentration of oxygen in their blood than healthy people. Describe the path by which oxygen goes from an alveolus to the blood. (2)
Through alveolar epithelium; Through capillary epithelium
Why do intercostal muscles allow the ribs to move? (2)
To enable the lungs to be ventilated by a tidal stream of air; thereby ensuring that the air within them is constantly replenished
Calculate the total volume of air breathed in and out per minute when the cyclist is cycling at 20kmh-1. Show your working. (2)
20 × 2.75 = 55 dm2
What is the trachea? (1)
A flexible airway made of muscle and lined with ciliated epithelium and goblet cells
(Refer to June 2011 paper) A doctor measured the volume of air in the lungs of two people over a period of 7 seconds. Both people were resting. One person was healthy. The other had emphysema. The results are shown in the table. The two people were breathing out during the time shown. What evidence in the table supports this statement? (1)
Volume of air in lungs decreases
Describe and explain the symptoms of pulmonary fibrosis. (4)
Weakness and fatigue; due to less oxygen being taken into blood, resulting in less respiration; Shortness of breath; due to thickened epithelium of alveoli which increases diffusion pathway and slows the rate of diffusion
When does air leave the lungs? (1)
When the air pressure inside the lungs is greater than the air pressure of the atmosphere
When does air enter the lungs? (1)
When the air pressure of the atmosphere is greater than the air pressure inside the lungs
The inhaler which the person used contained a substance that dilates bronchioles. Use this information to explain why curve A is different from curve B. (More air breathed out in curve B) (2)
Without inhaler narrower bronchioles; Less air is able to pass through
In healthy lungs, a gradient is maintained between the concentration of oxygen in the alveoli and the concentration of oxygen in the lung capillaries. Describe how ventilation helps to maintain this difference in oxygen concentration. (2)
(In alveolus) Brings in air containing a higher oxygen concentration; Removes air with a lower oxygen concentration
Describe two differences between the breathing of a person with emphysema and a person without emphysema. (2)
(In emphysema) A lower volume breathed in and out; Faster breathing
(Refer to exam q) The volume of air breathed in and out of the lungs during each breath is called the tidal volume. The breathing rate and tidal volume were measured for a cyclist pedalling at different speeds. The graph shows the results. Describe the two curves. (i) Tidal volume (ii) Breathing rate (2)
(i) Tidal volume increases steeply, then increase slows down after 10 to 15 kmh-1; (ii) breathing rate increases slowly then steeply after 10 to 15 kmh-1