smoking and disease

Smoking and Disease

1. Tar:-
Settles on the lining of the airways.
Stimulates goblet cells and mucous glands to enlarge and secrete excessive mucus.
Inhibits the cleaning action of cilia by destroying most of it or paralysing it.
Contains carcinogens which stimulate mutation to cause Lung Cancer.
EFFECT- Mucus accumulates in which bacteria, dirt and viruses are collected. Scar tissues and smooth muscles thickening cause the airway to become narrower. Infections develop in the mucus causing inflammation (Bronchitis/Chronic Bronchitis).
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Symptoms—severe cough, breathlessness.
Continuous inflammation stimulates phagocytes to leave the blood and line the airways. To do so, they release an enzyme, elastase, which destroys elastin in the walls of the alveoli. With reduced amount of elastin, the alveolar walls do not stretch and recoil much during breathing. This causes the bronchioles to collapse trapping air in the alveolus, making them burst (Emphysema). It reduces the surface area for gas exchange. Heavy coughing from bronchitis can also physically damage the alveolar walls.

2. Carbon monoxide:-
Diffuses into blood and binds with Hb more readily. Hb has a higher affinity towards carbon monoxide.
EFFECT- Reduces the carrying capacity of oxygen of Hb causing deficiency in oxygen for cells. As a result blood pressure increases. Increased blood flow can damage the linings of the coronary and carotid arteries which can lead to the build up of Atheroma (cholesterol, fibres, dead muscle cells and platelets), causing Atherosclerosis. Atherosclerosis in coronary arteries causes Coronary Heart Disease (Angina, Heart attack, Heart failure). Atherosclerosis in the carotid arteries cause them to burst. As a result blood leaks out and spread over the brain in a particular area. The brain tissue in that area is starved of oxygen supply and dies (Stroke).
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Symptoms—unable to control body parts(paralysis), dizziness, slurred speech, confusion, blurred vision, loss of vision.

3. Nicotine:-
Drug which is readily absorbed by blood and travels to brain.
EFFECT- Stimulates nervous system to reduce the diameter of arterioles and increase the secretion of adrenaline. This increases the heart rate and blood pressure. There is a decrease in blood supply to the extremities of body. It also increases the stickiness of platelets increasing the risk of blood clot.
Causes Cardiovascular diseases (Stroke, Atherosclerosis, Coronary Heart Disease).

The process of atherosclerosis restricts the flow of blood increasing the risk of blood to clot and form a thrombus.

Formation of Atheroma – Atherosclerosis

Formation of Thrombus – Thrombosis

Low Density Lipoproteins tend to deposit its cholesterol in tissues.
High Density Lipoproteins tend to remove cholesterol from tissues.