Smoking and lung disease Objectives Describe the effects of smoking on the mammalian gas exchange system, including the symptoms of chronic bronchitis, emphysema (COPD) and lung cancer Evaluate the data linking cigarette smoking to disease and early death.

Chemicals in cigarette smoke Cigarette smoke contains over 4000 chemicals. Three main chemicals: – Tar (a mixture of chemicals including over 50 known carcinogens) – Carbon monoxide – nicotine

Tar Settles on the lining of airways and damages cilia.

Tar - Short Term Effects Allergic reaction restricting airflow Paralyse cilia so unable to waft mucus away from lungs Stimulate mucus production by goblet cells and mucus blocks bronchioles Increased susceptibility to infections such as flu or pneumonia

Tar - Longer term effects Cough to clear airways which damages the airways and alveoli Lung lining becomes scarred, thickened and less flexible Smooth muscle around the bronchioles thickens reducing the lumen restricting air flow

Effects of Nicotine and Carbon Monoxide on the Cardiovascular System They pass from the lungs into the bloodstream causing changes to the circulation. Lead to increased risk of cardiovascular diseases such as – Atherosclerosis – Coronary heart disease (CHD) – Stroke

Nicotine Causes addiction Mimics action of neurotransmitters at synapses causing release of adrenaline which increases heart and breathing rate Arterioles constrict raising blood pressure. Those supplying the extremities constrict reducing blood flow and oxygen delivery Platelets are made stickier, increasing the risk of a blood clot or thrombus forming

Carbon Monoxide Enters red blood cells and combines with haemoglobin to form carboxyhaemoglobin. (CO combines much more readily than oxygen). The oxygen carrying-capacity of the blood becomes reduced. The lining of the arteries may also be damaged by carbon monoxide.

Smoking related diseases Lung cancer Chronic bronchitis emphysema COPD Task : Research and summarise the link between smoking and these diseases, include details of the symptoms and how smoking causes them use diagrams as appropriate

Analysing epidemiological Data

What can you conclude from these graphs?

Epidemiological evidence linking smoking to disease Regularly smoking increase you chance of dying prematurely by 3 50% of regular smokers die of a smoke related disease The more cigarettes smokes per day the greater likelihood of premature death A smoker is 18 times more likely to get lung cancer 25% of smokers die from lung cancer Stopping smoking reduces the chance of lung cancer COPD is rare in non smokers 98% people with emphysema are smokers 20% smokers have emphysema

Experimental evidence linking smoking to disease Early work was carried out with smoking dogs Very emotive Dogs smoking cigarettes without filters showed early signs of COPD and lung cancer When tar was rubbed on skin of mice they developed cancer Conclusion was that tar contained carcinogens

Another graphical example

Linking smoking and disease Evaluate the epidemiological and experimental evidence linking cigarette smoking to disease and early death. Objectives

Effects of Tar Short term effectsLonger term effects Tar settles on lining of airways and alveoli increasing diffusion distance for O 2 and CO 2. Can cause an allergic reaction, causing airways to contract and less airflow to alveoli. Paralyses cilia so unable to move mucus layer along. Goblet cells enlarge and release more mucus. Bacteria and viruses become trapped in mucus causing infections. Smoker’s cough to shift mucus. Damage to lining of airways/alveoli. Scar tissue develops. Smooth muscle thickens causing smaller airways and permanently reduced air flow. Epithelium damaged by frequent infections. Elastic tissue in lungs is damaged – alveolar walls lose elastic recoil, bronchioles collapse and trapped air in alveoli may cause them to burst.

Lung cancer Carcinogenic compounds (in tar) enter cells in lung. They cause mutations in the DNA in the nucleus. If the mutation affects the genes controlling cell division, uncontrolled cell division may occur, forming a tumour. Often starts at entrance to bronchi and can take years to develop. Symptoms – continuous coughing, shortness of breath, chest pain, coughing up blood.

Lung cancer

Chronic bronchitis Inflammation of lining of bronchi. Damage to cilia and overproduction of mucus. Symptoms – irritation in lungs, continual coughing, coughing up mucus (with bacteria and white blood cells. Increased risk of lung infection.

Emphysema Loss of elasticity in alveoli causes them to burst. Lungs have reduced surface area for gaseous exchange. Less oxygen in blood and therefore less delivered to cells. Symptoms – short of breath, harder to exhale, breathing becomes shallow and rapid, fatigue.

Emphysema

Chronic obstructive pulmonary disorder (COPD) A combination of diseases including chronic bronchitis, emphysema, asthma. At least 25,000 people die each year in the UK from the end stages of COPD.

Smoking Related Diseases Symptoms: Shortness of breath (dyspnea) Rapid, shallow breathing Fatigue Wheezing Sleep problems Weight loss Emphysema

Smoking Related Diseases Symptoms: Shortness of breath Mucus production Cough Wheezing Chest tightness Chronic obstructive pulmonary disease (COPD)

Smoking Related Diseases Symptoms: Persistent cough Coughing up of mucus Episodes of acute bronchitis Chronic bronchitis

Smoking Related Diseases Symptoms: Cough Shortness of breath Coughing up blood Chest pain Wheezing Hoarseness Loss of appetite/weight loss Lung cancer