Biology

#53 Summary of Smoking

1 Tobacco smoke contains tar, carbon monoxide and nicotine.

2 Tar settles on the epithelium lining the bronchi and bronchioles and stimulates inflammation, an increase in the secretion of mucus and an accumulation of phagocytes from the blood.

3 Damage to the airways and alveoli occurs in chronic obstructive pulmonary disease (COPD). In chronic bronchitis, the airways are obstructed by mucus and infection; in emphysema, alveoli are destroyed, reducing the surface area for gas exchange.

4 Tar contains carcinogens, which cause changes in DNA in bronchial epithelial cells, leading to the development of a bronchial carcinoma. This is lung cancer.

5 Some of the signs and symptoms of COPD are breathlessness, wheezing and constant coughing; two of the symptoms of lung cancer are coughing up blood and chest pains.

6 Carbon monoxide combines irreversibly with haemoglobin, reducing the oxygen-carrying capacity of the blood.

7 Nicotine stimulates the nervous system, increasing heart rate and blood pressure, and stimulating vasoconstriction, which reduces blood fl ow to the extremities.

8 Epidemiological evidence shows a strong correlation between smoking and lung diseases such as cancer; the link between smoking and lung cancer was confi rmed by experimental studies.

9 Smoking damages the cardiovascular system, increasing atherosclerosis and increasing the risk of coronary heart disease and stroke.

10 Atherosclerosis is the development of fatty tissue within the walls of arteries. Th e fatty material, known as atheroma, forms plaques within the artery walls. These roughen the lining of arteries, which may lead to thrombosis (blood clotting).

11 Coronary heart disease may be treated with drugs to lower blood cholesterol and blood pressure. Coronary artery by-pass surgery involves using a blood vessel from the leg, arm or chest to replace the part or parts of a coronary artery that are damaged. A heart transplant may be necessary, but it is an expensive operation and diffi cult to find donor

hearts, so very few are performed.

12 Primary health care can reduce mortality from coronary heart disease and strokes. Screening people for risk factors of coronary heart disease and stroke allows early intervention. Advertising and education can promote the benefi ts of exercise, not smoking, avoiding an excessive consumption of alcohol and eating a diet low in saturated fat. These alternatives to treatment and surgery may be more cost-eff ective in the long term, but they

depend on people being willing and able to change their lifestyle.

1. Multiple-choice test

1 Tar in cigarette smoke contains carcinogens and is mostly deposited in the bronchi.

What is the effect of these carcinogens?

A cause mutations in bronchial epithelial cells
B destroy the cilia in the bronchi
C stimulate goblet cells to produce more mucus
D reduce the diameter of the bronchi

2 Which component of tobacco smoke binds with haemoglobin to form carboxyhaemoglobin?

A carbon monoxide
B carcinogens
C nicotine
D tar

3 What is not a symptom of emphysema?

A alveoli burst
B alveoli lose elastic fibres
C bronchi are blocked by tumours
D the total surface area of the alveoli is reduced

4 Two lifelong cigarette smokers, X and Y, both have persistent coughs. X also has difficulty breathing out and Y is getting much thinner. From these symptoms it is possible that:

A X has bronchitis and Y has emphysema.
B X has emphysema and Y has chronic obstructive pulmonary disease.
C X has chronic obstructive pulmonary disease and Y has lung cancer.
D X has lung cancer and Y has bronchitis.

5 Both carbon monoxide and nicotine are absorbed into the blood from tobacco smoke.

What describes their effects on the body?

6 What is the sequence of events leading to atherosclerosis?

1 blood clot forms at site of plaque
2 phagocytes attracted to site of damage
3 low density lipoproteins transport cholesterol to artery
4 damage to the lining of an artery
5 atheroma builds up and breaks through the endothelium

A 1 ? 2 ? 3 ? 4 ? 5
B 2 ? 3 ? 5 ? 1 ? 4
C 4 ? 2 ? 3 ? 5 ? 1
D 5 ? 1 ? 4 ? 2 ? 3

7 Which of the following explains the increased risk of stroke, caused by smoking tobacco?

A CO increases the blood pressure and increases the chance of a blood vessel in the brain bursting.
B Carcinogens increase the blood pressure and increase the chance of a blood vessel in the brain bursting.
C Nicotine increases the chance of a blood clot blocking a blood vessel in the brain.
D Tars increase the chance of a blood clot blocking a blood vessel in the brain.

8 Which observation is experimental evidence that smoking tobacco causes lung cancer?

A Most people who develop cancer are smokers.
B Death rates from lung cancer are highest in people who smoke more than 25 cigarettes per day.
C Lung cancer was a rare disease until smoking became common in the 20th century.
D When substances extracted from tar in cigarette smoke were painted onto the skin of mice, the mice developed tumours.

9 Which dietary factors increase the risk of coronary heart disease?

A high intake of fruit and vegetables
B high intake of saturated fat and cholesterol
C low intake of sodium chloride and alcohol
D moderate intake of unsaturated fat

10 What would not form part of an effective screening programme for CHD?

A screening for high blood pressure
B screening for high cholesterol
C monitoring heart rhythms
D screening blood samples for bacterial infection a

Answers to Multiple choice test

1. A

2. A

3. C

4. C

5. A

6. C

7. C

8. D

9. B
10. D

2. End-of-chapter questions

1 Which of the followingsubstances in tobacco smokedamage the gas exchange system?

A CO and carcinogens

B CO and nicotine

C carcinogens and tar

D nicotine and tar

2 What are the symptoms of lung cancer?

A chestpain, coughing up blood,shortness of breath

B difficulty breathing, highblood pressure, smoker'scough
C dizziness, high blood pressure, high sersting pulse rate
D poor oxygenation of the blood, shortness of breath, smoker's cough

3 Which substance in tobacco smoke decreases the oxygen-carrying capacity of haemoglobin?

A carbon dioxide

Bcarbon monoxide

4. Which of the following is an example of an epidemiological investigation?

A carrying out a clinical trial of a drug for heart disease

B measuring the tar content of different brands of cigarettes

Cresting substances to find out if they are carcinogenic

D resting the hypothesis that there is a correlation between the number of people who smoke and the number of cases oflung disease

5. Cigarettesmoke contains tar, nicotine and carbon monoxide.

a Describe the effect of tar on the lining of the bronchi in the lungs.

b Describe the effects of nicotine and carbon monoxide on the cardiovascular system.

6. The figure shows photomicrographs of alveoli from

1 a non-smoker (x 200) and 2 a smoker (x 50).

a Use the figure to describe how the lungs of smokers differ from the lungs of non-smokers. [4]

b Smokers with lungs similar to the lungs shown in photomicrograph 2 have poor health.

i Describe the symptoms that these people may have. [4]

ii Explain how the structure of the lungs is responsible for this poor health. [3]

[Total: 11]

7 a A person is diagnosed as having lungcancer. Describe how the lungcancer developed.[6]

The figure shows the numbers of deaths from lung cancer of men and women aged between 35 and 69 in the UK between 1950 and 2007.

b i Explain the advantage of calculating death rates as 'per 100000 of the population'.[2]

ii Use the information in the figure to compare the change in men's death rate from lung cancer between 1950 and 2007 with that in women. [4]

iii Suggest explanations for the changes in death rates shown in the figure. [4]

[Total: 16]

8 Cardiovascular diseases such as coronary heart disease (CHD) and stroke are major causes of illness and death throughout the world. People diagnosed with these diseases often require expensi e treatments such as surgery orlong-term drug treatment.

a Explain the difference between CHD and stroke. [2]

b Outline how coronary by-pass surgery is used in the treatment of CHD. [2]

The treatment of people with cardiovascular diseases costs the countries of the European Union (EU) about 10%

of their total expenditure on health.

c Describe the steps that health authorities and governments could take to prevent people requiring this expensive treatment. [6]

d Discuss the difficulties in reducing the number of people who develop cardiovascular diseases. [4]

[Total: 14]

3. End-of-chapter answers

1 C
2 A
3 B
4 D

5 a tar stimulates, goblet cells/mucous glands, to secrete more mucus;
paralyses/destroys, cilia;
mucus not moved up the, bronchioles/bronchi, trachea/airways;
mucus accumulates in the airways;
bacteria multiply within the airways;
(leads to) chronic bronchitis;
tar contains, carcinogens/named carcinogen e.g. benzpyrene;
(tar) settles on bronchial, epithelial cells/epithelium;
mutation(s)/change to DNA;
growth of tumour;
bronchial carcinoma/lung cancer;

b nicotine: increases heart rate;
increases blood pressure;
increases chance of blood clotting/promotes thrombosis;
decreases fl ow of blood to, extremities/fi ngers/ toes;
carbon monoxide: combines (irreversibly) with haemoglobin;
forms carboxyhaemoglobin;
reduces oxygen-carrying capacity of, haemoglobin/ blood;
damages lining of arteries;
promotes atherosclerosis;

Exam-style questions

6 a fewer alveoli;
larger air spaces;
fewer capillaries;
scar tissue in bronchioles/bronchi;
few/no cilia;
few/no goblet cells;
enlarged mucous glands;
enlarged smooth muscle;
may be pre-cancerous/cancerous cells;
tumour/bronchial carcinoma; [max. 4]

b i difficulty breathing/breathlessness;
wheezing;
tiredness;
not able to do (much) exercise; [max. 4]

ii small(er) surface area for gas exchange;
less oxygen absorbed;
poor oxygenation of the blood;
bronchi/bronchioles/airways blocked by mucus;
increased resistance to fl ow of air; [max. 3]
[Total: 11]

7 a (tar) settles on bronchial epithelial cells/epithelium;
carcinogens/named carcinogen (in tar) e.g. benzpyrene;
causes mutation(s)/change to DNA (in epithelial cells);
in (proto onco)genes that control cell division/ mitosis;
cancer cells do not respond to signals/growth factors/other cells;
cancer cells divide uncontrollably;
no programmed cell death/apoptosis;
cells do not diff erentiate/become specialised;
cells form tumour/bronchial carcinoma;
tumour supplied with blood vessels/lymph vessels; [max. 6]

b i data are standardised;
populations diff er from year to year;
allows valid comparisons; [max. 2]

ii death rate for men always higher than for women;
use of the data to make a comparison between death rates for men and women;
death rate for men rises to a maximum in 1966 and then decreases;
death rate for women increases later than for men;
death rate for women increases to a maximum in late 1980s/1990 and then decreases;
decrease in death rate for women not as steep as for men;
use of the data to show increase or decrease in death rate for men or women; [max. 4]

iii men started smoking earlier than women;
more men smoked than women;
smoking became less popular among men from 1950s/1960s onwards;
increase in number of women who smoked from the same time;
link made between smoking and cancer;
anti-smoking campaigns;
lung cancer takes a long time to develop/be diagnosed;
decrease in death rate did not happen until many years after decrease in popularity of smoking; [max. 4]

[Total: 16]

8 a CHD: narrowing of coronary arteries that supply oxygenated blood to heart muscle;
stroke: interruption of blood supply to part of the brain as a result of blockage or bursting of an artery (or arteries), leading to death of brain cells; [2]

b vein taken from the chest, arm or leg;
attached to coronary artery either side of blockage;
may be one or more by-passes if there are several blockages in the coronary arteries; [max. 2]

c health promotion campaigns/publicity/leafl ets/ advertising;
provide information about maintaining fitness/ healthy eating/stopping smoking/reducing alcohol intake;
increase tax on tobacco/alcohol to reduce consumption;
provide health warnings on foods that are high in saturated fat;
print health warnings on tobacco products;
ban smoking in public places;
provide drugs for, hypertension/high blood cholesterol;
provide screening for, risk factors/high blood pressure/high blood cholesterol;
in people at greatest risk;
provide, leisure facilities/fi tness centres; [max. 6]

d many risk factors involved;
some of which are genetic factors;
factors that cannot be modifi ed (e.g. sex, age, genes);
people are resistant to advice about changing lifestyle/diet;
cardiovasular disease most common in lower income groups;
who may not be able to aff ord to buy healthier food/use leisure facilities;
people at most risk may not be screened for risk factors; [max. 4]
[Total: 14]

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Biology