1. emphysema (chronic obstructive pulmonary disease or COPD)
The Effects of Smoking
Describe the effects of smoking on the mammalian gas exchange system, with reference to the symptoms of
chronic bronchitis
emphysema (chronic obstructive pulmonary disease or COPD)
lung cancer

2. Constituents of cigarette smoke that cause damage to health
Cigarette smoke contains over 4000 different chemicals. The main problems are caused by :
Tar, a mixture of substances including carcinogens (chemicals that cause cancer)
Nicotine
Carbon Monoxide

3. Short Term Effects of Tar on Gas Exchange System (NB: tar does not pass through lung tissue into blood stream)
Cause
Damage to gas exchange system
Tar settles on lining of airways and alveoli
Chemicals in tar causes an allergic reaction
Tar paralyses or destroys cilia of ciliated epithelium
Tar stimulates over-production of mucus from goblet cells and mucus glands
Mucus trapped and collects in airways
Microbes trapped in airways

4. Short Term Effects of Tar on Gas Exchange System (NB: tar does not pass through lung tissue into blood stream)
Cause
Damage to gas exchange system
Tar settles on lining of airways and alveoli
tar layer slows gas exchange by increasing diffusion distance for gases
Chemicals in tar causes an allergic reaction
smooth muscle in airway walls contracts. Reduces lumen diameter, restricts flow of air in and out of airways
Tar paralyses or destroys cilia of ciliated epithelium
Cilia no longer move mucus out of airways
Tar stimulates over-production of mucus from goblet cells and mucus glands
Mucus collects in airways, bacteria and viruses become trapped in mucus. Cilia unable to move it.
Mucus trapped and collects in airways
Can cause blockages in small bronchioles preventing air flow in and out
Microbes trapped in airways
Likely to cause infection in lungs,
eg: pneumonia and influenza

5. Long Term Effects of Tar on Gas Exchange System
Cause
Effect on gas exchange system
Irritation of airways by mucus and microbes
Frequent coughing damages cells lining the airways,
Frequent coughing thickens the smooth muscle layer
Constant infections encourage more white blood cells to pass into lung tissues
Damaged alveoli and bronchioles cannot stretch and recoil properly
Deposition of tar which contains carcinogens on lung tissue

6. Long Term Effects of Tar on Gas Exchange System
Cause
Effect on gas exchange system
Irritation of airways by mucus and microbes
leads to frequent and persistent coughing
Frequent coughing damages cells lining the airways,
then damaged cells are replaced by thicker less flexible scar tissue
Frequent coughing thickens the smooth muscle layer
then the thicker muscle layer reduces the lumen of the airway so air flow in and out is restricted
Constant infections encourage more white blood cells to pass into lung tissues
white blood cells produce elastase enzyme which breaks down elastic tissue in alveoli and bronchioles
Damaged alveoli and bronchioles cannot stretch and recoil properly
so air is not pushed out of alveoli, alveoli may burst due to coughing, bronchioles may collapse
Deposition of tar which contains carcinogens on lung tissue
carcinogens taken into nucleus of cells, causes mutations to DNA. Mutation of genes can cause uncontrolled cell division ie: a tumour

7. Diseases of Gas Exchange system associated with smoking
Lung Cancer
Bronchitis
Emphysema
COPD (chronic obstructive pulmonary disease)

8. Lung Cancer
SEM of a lung cancer cell. Cancer cells divide rapidly in a chaotic, uncontrolled manner. They may clump to form tumours, which invade and destroy surrounding tissues. Lung cancer is a common form of cancer, frequently associated with smoking tobacco. It often develops at the entrance to the bronchi It causes a persistent cough, shortness of breath and chest pain. Blood may be coughed up in sputum. Cancer may spread to other areas of the body. Treatment includes surgical excision of the affected areas of the lung, with radiotherapy and chemotherapy.

9. Lung cancer Outside lung Inside lung Black deposits of tar in tissues
Large cancerous tumour

10. Lung cancer

11. Signs and Symptoms Often no symptoms early on Later symptoms maybe:
cough, shortness of breath, wheezing, chest pain, and coughing up blood

12. Bronchitis

13. Bronchitis Inflammation of the airway lining, damaged cilia, increased mucous production. Persistent cough, mucus filled with microbes and white blood cells

14. Signs and symptoms of Bronchitis
Cough
Production of mucus (sputum), either clear or white or yellowish-gray or green in color
Shortness of breath, made worse by mild exertion
Wheezing
Fatigue
Slight fever and chills
Chest discomfort
Frequent respiratory infections (such as colds or ‘flu) with a worsening productive cough

15. Emphysema

16. Emphysema
Damaged alveoli
Normal alveoli

17. Emphysema
SEM of human lung tissue affected by emphysema. Emphysema is a disease in which the alveoli of the lung become enlarged and the walls separating them are damaged. This damage occurs as a result of elastase enzyme breaking down the elastic fibres which allow the alveoli to expand and recoil. There is difficulty exhaling. Surface area for gaseous exchange is reduced, restricting oxygen uptake. This may cause breathlessness, bluish skin, and heart or respiratory failure. Occurrence of emphysema is strongly associated with smoking. Treatment of emphysema is with drugs and the cessation of smoking.

18. Emphysema signs and symptoms
Shortness of breath, shallow breathing
Wheezing, difficulty breathing out
Fatigue, extreme tiredness
Heart failure
Cyanosis / blue tinge to skin
High blood pressure to lungs
Enlarged right side of heart

19. Learning Outcome Describe the effects of nicotine and carbon monoxide
in tobacco smoke on the
cardiovascular system
with reference to the course of events leading to
atherosclerosis
coronary heart disease
strokes.

20. Match the effect that CO and nicotine have on the body to the damage that they cause
Sort the cards into 6 pairs

21. Remember Nicotine and Carbon Monoxide enter the lungs and pass through the lung surface into the blood
Effects
Consequences
Nicotine stimulates release of adrenaline
Adrenalin:
Increases heart rate
Increases breathing rate
Constricts arterioles
Increases blood pressure
Nicotine causes constriction of the arterioles
Reduces blood flow to extremities
May lead to necrosis of tissues-lack of O2 and glucose
In extreme cases may result in amputation
Nicotine makes platelets more sticky
Increases the risk of blood clot or thrombus forming
Nicotine mimics action of neurotransmitters at synapses
Makes the smoker feel more alert
Carbon monoxide combines with haemoglobin to form carboxyhaemoglobin
Reduces the oxygen carrying capacity of blood
When exercising heart rate and breathing rate rise more than normal
Carbon monoxide causes damage to arterial endothelial linings
Damage to lining makes it more likely that plaques develop

22. Development of Atheromas (Atherosclerosis)
Damage to the arterial endothelium by CO or hypertension
Cholesterol, fatty deposits and cellular waste are deposited under the damaged area in the wall, which is then repaired
Inflammation at the site stimulates monocytes to infiltrate the area
Monocytes differentiate into macrophages which ingest the cholesterol and turn into “foam cells”. This is what forms the “plaque”
These changes also stimulate smooth muscle cells to multiply and form a “cap”
The whole area increases in size and extends out into the lumen of the artery restricting blood flow.
The atheroma may finally break through the repaired endothelium again and release some of the lumps of fatty deposit into the blood stream. This can increase the likelihood of blockages in small arteries.

23. Development of Atheroma in arterial walls (Atherosclerosis)

24. Reduction of arterial lumen by atheroma

25. Watch real player video on atherosclerosis

26. Essay Carbon Monoxide contribute to the occurrence of
Explain how Nicotine and
Carbon Monoxide contribute to the occurrence of
Coronary Heart Disease and Strokes