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The Effects of Smoking Describe the effects of smoking on the mammalian gas exchange system, with reference to the symptoms of chronic bronchitis emphysema.

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Presentation on theme: "The Effects of Smoking Describe the effects of smoking on the mammalian gas exchange system, with reference to the symptoms of chronic bronchitis emphysema."— Presentation transcript:

1 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 ) CauseDamage 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) CauseDamage 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 airwaysLikely to cause infection in lungs, eg: pneumonia and influenza

5 Long Term Effects of Tar on Gas Exchange System CauseEffect 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 CauseEffect on gas exchange system Irritation of airways by mucus and microbesleads 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 Black deposits of tar in tissues Large cancerous tumour Outside lungInside lung

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 Damaged alveoliNormal 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 EffectsConsequences Nicotine stimulates release of adrenalineAdrenalin: Increases heart rate Increases breathing rate Constricts arterioles Increases blood pressure Nicotine causes constriction of the arterioles Increases blood pressure Reduces blood flow to extremities May lead to necrosis of tissues-lack of O 2 and glucose In extreme cases may result in amputation Nicotine makes platelets more stickyIncreases 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 lumen atheroma

25 Watch real player video on atherosclerosis

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


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