Collins uses simple, relatable imagerylike sipping coffeewhile inviting us to reflect on the world beyond our sight, a theme common in his work
(1) A $1.5 billion expansion pipeline reshaping the interstate map Buc-ee's is in the most aggressive expansion phase in its history
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Preparation of CSE CSE was prepared as previously described 39
Effects of Tobacco Smoke (Cambridge (CIE) O Level Biology): Revision Note Exam code: 5090 Written by: Phil Reviewed by: Lra Marie McIvor Updated on Effects of Tobacco Smoke Chemicals in tobacco smoke Smoking causes chronic obstructive lung disease, coronary heart disease and increased risks of several different types of cancer, including lung cancer Chemicals in cigarettes include: Tar - a carcinogen (a substance that causes cancer)) Nicotine - an addictive substance which also narrows blood vessels Carbon monoxide - reduces the oxygen-carrying capacity of the blood Tar Tar is a carcinogen and is linked to increased chances of cancerous cells developing in the lungs Tar also contributes to COPD, which occurs when chronic bronchitis and emphysema , two different diseases which are frequently linked to smoking, occur together Chronic bronchitis is caused by tar which stimulates goblet cells and mucus glands to enlarge, producing more mucus Tar destroys cilia , inhibiting the cleaning of the airways, and mucus (containing dirt, bacteria and viruses) builds up blocking the smallest bronchioles A smoker's cough is an attempt to move the mucus but it damages the epithelia resulting in scar tissue The scar tissue narrows the airways and makes breathing difficult Emphysema Emphysema develops as a result of frequent infection , meaning phagocytes are attracted to the lungs where they release elastase - an enzyme that breaks down the elastin in the alveoli walls , to enable them to reach the surface where the bacteria are Without adequate elastin, the alveoli cannot stretch , so they recoil and many burst The breakdown of alveoli results in the appearance of large air spaces, reducing the surface area for gas exchange and making sufferers breathe more rapidly As it progresses, patients become breathless and wheezy - they may need a constant supply of oxygen to stay alive The breakdown of alveoli in emphysema diagram The breakdown of alveoli in emphysema reduces the surface area for gas exchange Carbon monoxide Carbon monoxide binds irreversibly to haemoglobin , reducing the capacity of blood to carry oxygen This puts more strain on the breathing system as breathing frequency and depth need to increase in order to get the same amount of oxygen into the blood It also puts more strain on the circulatory system to pump the blood faster around the body and increases the risk of coronary heart disease and strokes Nicotine Nicotine narrows blood vessels so puts more strain on the circulatory system and increases blood pressure Narrow blood vessels are more likely to become clogged with fat, including cholesterol - if this happens in the coronary artery, this causes coronary heart disease This means the heart muscle cells do not get sufficient oxygen and so less aerobic respiration takes place To compensate the cells respire anaerobically , producing lactic acid which cannot be removed (due to lack of blood supply) This creates a low pH environment in the cells causing enzymes to denature and eventually, heart muscle cells will die If enough die this can cause a heart attack Another effect of nicotine is low birth weight in babies born to mothers who smoke during their pregnancy Nicotine narrows the blood vessels in the umbilical cord , which reduces the supply of oxygen and important food molecules to the fetus The placenta can also separate from the uterus, causing bleeding, premature birth and sometimes, miscarriage or stillbirth Smoking & Lung Cancer: Is There a Link The majority of cases of lung cancer are caused by smoking Graph showing correlation between numbers of adults who smoke and lung cancer rates over time Note that as the general trend shows that as the numbers of adults who smoke decreases, so does the lung cancer rates a few years later (as cancer takes some time to develop) The trend in the rate of developing lung cancer for women has been increasing, while in men it is decreasing This is because numbers of female smokers unlike men continued to increase in the 1950s and 1960s before starting to fall As cancer takes some years to develop, a fall in female rates of lung cancer is likely to occur later Unlock more, it's free
