Chpater 9.2

Question 1

COPD

Answer 1

• Tar can also cause Chronic obstructive pulmonary disease (COPD)
• COPD includes a range of lung-based diseases, such as asthma, chronic bronchitis and emphysema
• Tar stimulates goblet cells in the ciliated epithelium and causes them to become enlarged. In turn, the goblet cells produce more mucus
• This destroys the cilia in the trachea and prevents them from sweeping mucus away from the lungs
• The mucus contains bacteria, dust and other microorganisms and can then block narrow bronchioles, causing coughing, scar tissue and infection
• The infection attracts phagocytes to the lungs and the phagocytes release elastase, an enzyme which damages the elasticity of the alveolar walls
• Without enough elastin, the alveoli break down and may burst. This creates large air spaces in the alveoli and patients become wheezy and breathless. Once the disease progresses, people often need a constant supply of oxygen to stay alive

Question 2

Describe the signs and symptoms of Chronic obstructive pulmonary disease (COPD).

Answer 2

Symptoms include shortness of breath, a chronic or persistent cough, chest tightness, wheezing and difficulty breathing when exercising or during any physical activity.

Question 3

Tar is a chemical in cigarettes and is a

Answer 3

carcinogen, which means it causes cancer

Question 4

Cancer occurs if

Answer 4

mutations affect the regulation of mitosis in cells. Tar forms a sticky layer inside the lungs and increases the rate of mutations in the DNA of bronchial epithelial cells, potentially leading to a tumour

• Tumours develop if mutations occur in oncogenes or tumour-suppressor genes of the bronchial epithelial cells. This causes uncontrolled mitosis which develops into a mass of cells in the lumen of the airways
• The tumour becomes larger because it has no method of programmed cell death and survives because it develops its own blood supply (vascularisation)
• The tumour then starts to interfere with the normal working of the lungs, such as by squeezing against blood vessels or cancer cells entering into the lymphatic system, where they may develop another tumour

Question 5

Symptoms of lung cancer include

Answer 5

coughing up blood, a persistent cough, coughing an increased amount of mucus, back or shoulder pain, wheezing and breathing difficulties and sudden weight loss

Question 6

Carbon monoxide

Answer 6

Once inhaled, carbon monoxide in cigarettes binds to haemoglobin instead of oxygen

This is because chemically carbon monoxide has a much higher affinity for -Once inhaled, carbon monoxide in cigarettes binds to haemoglobin than oxygen

• When this happens, oxygen cannot bind to haemoglobin and carboxyhaemoglobin (COHb) is formed instead of oxyhaemoglobin
• This decreases the amount of oxygen delivered to cells for aerobic respiration and cells may have to respire anaerobically instead
• This forces the heart to work harder to pump and deliver adequate oxygen, increasing heart rate and causing breathlessness
• Carbon monoxide also promotes the release of free radicals
• Carbon monoxide can also cause platelets and neutrophils to stick together, affecting the ability of white blood cells to fight infection

Question 7

free radicals

Answer 7

peroxides and superoxides

Question 8

The drug nicotine has a similar structure to acetylcholine. Suggest the effects on brain neurons of inhaling nicotine from a cigarette.

Answer 8

Nicotine will fit into membrane receptors and is not broken down by enzymes. This means that action potentials are generated for a long period of time.

Question 9

Nicotine & Carbon Monoxide Effects

Answer 9

-Nicotine and carbon monoxide in cigarettes affect the ability of the cardiovascular system to function properly

-Nicotine is the addictive component of cigarettes. It causes vasoconstriction, which is the narrowing of blood vessels

• Vasoconstriction limits the flow of blood around the body, increases blood pressure and makes it harder for oxygen to reach all body cells
• This lack of oxygen can force cells to respire anaerobically, creating lactic acid
• Nicotine can also make platelets ‘sticky’ and they clump together, potentially forming a thrombosis (blood clot)