I91121 3I4I5I 6 3. TOPIC: Etiology (cause of the disease) Common causes of human
ID: 3520134 • Letter: I
Question
I91121 3I4I5I 6 3. TOPIC: Etiology (cause of the disease) Common causes of human disease include: infection (by viruses or bacteria), trauma, mutated genes, age-related degeneration. Sometimes the causes of a disease not yet known; physicians may propose possible causes for certain diseases based on scientific evidence collected from patients. For lung cancer, provide a paragraph describing what is currently known about the cause(s) lung cancer. Include a discussion of HOW the causative agent(s) impairs respiratory system anatomy and physiology.Explanation / Answer
Lung cancer or lung carcinoma: It is one type of cancer, in which the cells of lungs can grown in uncontrolled manner. Sometimes this growth can spread beyond the lungs (nearby tissues) called metastasis. Smoking is the biggest risk factor causing around 9 out of 10 lung cancer cases.
Causes of lung cancer:
1. Smoking: Smoking has been directly linked to lung cancer. Smoking damages the cells that line lungs. The length of smoking is more important than the number of cigarettes smoked.
2. Air pollution: The level of air pollution that the lungs are exposed to also increases the risk of causing lung cancer.
3. Radon gas exposure: Radon gas is a radioactive gas which can build up in buildings and homes. High indoor levels of radon cause lung cancer.
4. Exposure to some chemicals: Substances like asbestos and silica which are commonly found at workplace in chemical industry can cause lung cancer.
5. Family history of disease: Having a family history of the disease can also increase the risk of having lung cancer.
6. Lowered immunity: People with organ transplants take drugs which tend to lower immunity. Also HIV and AIDS also lower immunity. This can cause lung cancer as the ability to fight with diseases is reduced.
Smoking (Causative agent) impairs respiratory system:
The smoking can incorporate nicotine in blood and this chemical substance can interact and kill the neutrophils (white blood cells). Generally in body neutrophils (white blood cells) can fight against infections. Another substance present in the tobacco is tar and it can impair the cilia. The main work of the cilia is to collect dust and foreign particles. Germs are trapped by the mucus and sweep it out via coughing. Smoking also tends to destroy the cilia (fine hairs that line the respiratory tract). Damaged cilia causes formation of extra mucus accumulation leading to smoker’s cough. Smoking also tends to damage air sacs present in the lungs. It also affects the elasticity of lungs causing problems during breathing. A study in mice has shown that chronic exposure of mice to smoking reduced the number of dendritic cells in the lungs thereby decreasing the ability of lungs to mount adaptive response via virus specific antibodies. Therefore, smoking causes increased susceptibility to colds, chronic and respiratory infections.