B7 Non-Communicable Diseases

• the link between risk factors and diseases is called a correlation. it is useful for doctors to find correlations between lifestyle choices and diseases but this is the first step. doctors and scientists need to do lots of research to discover if there is a causal mechanism. a causal mechanism explains how one factor influences another through a biological process
• cells in our body divide on a regular basis in a sequence called the cell cycle. a tumour forms when control of this sequence is lost and cells grow in an abnormal, uncontrolled way
• benign tumours are growths of abnormal cells contained in one place, usually within a membrane. they do not invade other parts of the body but can grow very large very quickly. if this growth causes pressure to an organ, this growth can be life threatening.
• malignant tumour cells can spread around the body, invading neighbouring healthy tissue. a malignant tumour is often referred to as cancer. the initial tumour may split up, releasing small clumps of cells into the blood stream. they circulate and are carried to different parts of the body where they may lodge into another organ. then they continue dividing uncontrollably and form secondary tumours.
• the causes of cancer include genetics, a result of mutations (changes in the genetic material), exposure to ionising radiation like UV light and X-rays
• • radiotherapy- when the cancer cells are destroyed by targeted doses of radiation, this stops mitosis in cancer cells but can also damage healthy tissue.
• cancer can be treated in 2 main ways:

  • radiotherapy- when cancer cells are destroyed by targeted doses of radiation. this stops mitosis in the cancer cells but also can damage healthy tissue
  • chemotherapy- where chemicals are used to either stop the cancer cells dividing or make them 'self-destruct'
• after smoking a cigarette about 10% of the blood will be carrying carbon monoxide rather than oxygen, this can lead to a shortage of oxygen. this is why smokers often have difficulty breathing, especially when exercising, they get breathless quickly
• the cilia in the trachea and bronchi are anaesthetised by some of the chemicals in tobacco smoke. they stop working for a while and allow dirt and pathogens down into the lungs. tobacco smoke also contains tar which is a sticky black chemical that accumulates in the lungs, turning them from pink to grey. tar is also a carcinogen
• if you eat more food than you need, the excess is stored as fat. this over a long period of time can lead to obesity
• cardiovascular diseases are diseases of the heart and blood vessels, they are non-communicable so cannot be passed from person to person.
• coronary arteries branch out of the aorta and spread out into the heart muscle, they provide oxygen to the muscle cells of the heart. the oxygen is used in respiration to provide energy for contraction
• in coronary heart disease, layers of fatty material build up inside the artery, causing it to narrow. this reduces blood flow so leads to a lack of oxygen for the heart muscle. in extreme cases, this can lead to a heart attack when the heart is starved of oxygen
• statins are drugs that reduce the level of cholesterol in the blood, slowing down the rate that fatty material builds up in the arteries. although they can have unwanted side effects like liver disease.
• when coronary heart disease becomes too bad, it can cause almost a total blockage of a coronary artery. to treat this, we use a stent. a stent is a tube that is inserted into the artery to keep it open so blood can flow normally. although it doesn't prevent other regions from narrowing and doesn't treat the underlying causes of the disease
• national policies that help people lose weight

  reducing amount of sugar added to foods and drinks, adding a tax on high sugar/ fat foods, education on health, showing nutritional information on labels and menus in restaurants