Causes of death

Old Age 

The second law of thermodynamics explains that systems tend towards greater entropy, or disorder. While initially successful, the body starts to lose the battle against disorder as the general metabolism alters, and the body degenerates (catabolizes) at a faster rate than it regenerates (anabolizes). Brain and muscle cells decrease, and some newly created cells may not be as viable, due, for example, to transcription errors in the DNA that forms the code for the makeup of an individual. Proteins that constitute cells can also change with age, which is what causes wrinkles. Others believe that a natural clock tells the body via hormones to shut down and cease operating, a belief supported by the existence of such systems at the cellular level in the form of programmed cell death. Yet another theory suggests that collagen cross-linking of proteins inhibits passage of materials and causes aging. Additional information about aging is being found in many souces. For example, the Associated Press reported on June 2, 1998 on an article in Nature Genetics. Gabrielle Boulianne of the University of Toronto discovered that fly life spans could be increased up to 40 percent by inserting a gene in motor neurons to make them produce more superoxide dismutase. This enzyme prevents the alteration of excess oxygen in cells into harmful substances, a sort of "cellular rusting." Clearly the search for the fountain of youth has not ended.

Thrombi and Emboli 

Thrombi (singular thrombus) are clots that form in the blood vessels of and leading to the heart; emboli (singluar embolus) are air bubbles, blood clots or foreign bodies travelling through the body. Both can lead to a condition known as ischemia, when the blood flow to an organ is cut off, thus preventing the critical waste removal and oxygen and glucose supply integral to the functioning of all cells.

Ischemic heart disease 

Thrombi or emboli that lodge in heart vessels will both cause a heart attack. When the tissue is not actually dying, the condition is called angina and will cause pain in the shoulders or elsewhere. However, often times, the deprival of nutrients will cause actual death of tissue, and a prolonged heart attack will cause death. As the American Heritage Dictionary explains, a heart attack is "Acute myocardial infarction typically resulting from an occlusion or obstruction of a coronary artery and characterized by sudden, severe pain in the chest that often radiates to the shoulder, arm, or jaw." For more information, visit the American Heart Association.

Cerebro-vascular disease

Cerebro, referring to the brain, and vascular, referring to vessels, essentially means stroke. Strokes can be caused by both emboli lodging in vessels leading to the brain and the rupturing of blood vessels in the brain caused by hypertension. The brain is a very sensitive organ that requires a constant blood flow or else irreversible damage will result. Additional information can be found at Washington University in St. Louis.

Cancer 

Cancer is the uncontrolled growth of cells resulting in tumors that then spread and harm others parts of the body. A variety of treatments have been found and are being sought for the various types of cancer, but still it is often fatal. The ever-helpful American Heritage Dictionary explains here that we are talking about "Any of various malignant neoplasms characterized by the proliferation of anaplastic cells that tend to invade surrounding tissue and metastasize to new body sites."

Cancer of lung, trachea, bronchus

Lung cancer is now the leading cause of death from cancer, having more than tripled in death rate from 1950 to 1985. It is most often the result of cigarette smoking. Cigarettes are loaded with carcinogens (chemicals that causes cancer). The cancerous tissue grows rapidly so that it is essentially destroyed for the passage of air, and the area around it fails to take in air. The cilia that remove particles that arrive in the lungs along with air are also hurt by elements in cigarette smoke and are not even present in cancerous cells.

Cancer of stomach

Although deaths from stomach cancer have decreased, it is still a serious issue. Symptoms are very vague, including indigestion, bleeding, nausea and loss of appetite. Risk factors include being over 55, male, Black, outside the United States and having stomach bacteria, pernicious anemia, acholrydia and gastric atrophy, exposure to certain dust and fumes.

Cancer of female breast

Breast cancer is the second leading cause of cancer death (behind lung cancer) in women, developing in one in nine American women. It is detected by mammography (x-rays) or physical exam. Although the cause is not known, it occurs predominantly in older women.

Disease

The American Heritage Dictionary explains that a disease is "A pathological condition of a part, an organ, or a system of an organism resulting from various causes, such as infection, genetic defect, or environmental stress, and characterized by an identifiable group of signs or symptoms." Some, of course, lead to death more frequently than others, a condition varying according to societal factors, genetic composition and medical development. For more information about diseases, try here or Yahoo.

Bronchitis, emphysema, asthma

Emphysema, the abnormal increase in air space size in the lungs that can be the result of preventing alveoli constriction that makes breathing harder, is also often a result of smoking, though it can also be the result of air pollution, and it is the fourth largest cause of death in the United States. Bronchitis, the chronic inflammation of the bronchial tube's mucous membrane, and asthma, a constriction of passages causing labored breathing, are a related respiratory illnesses.

Chronic liver disease and cirrhosis

Cirrhosis is caused by alcohol abuse, poor nutrition or infections such as hepatitis. It occurs when functional liver cells are replaced by fibrous, nonfunctional ones. Drinking alcohol is ethanol, CH₃CH₂OH, which is broken down in the liver by enzymes to acetaldehyde (which in turn causes intoxication by release of adrenalinelike agents), CH₃CHO, which removes two hydrogens and reduces NAD⁺. These extra energy-carrying molecules reduce the need to break down sugars, amino acids and fatty acids, instead making them fat in the liver. The mitochondria, where energy is coverted in cells, also are swollen because the electron transport chain works to process NADH but does not engage in the Krebs cycle. The endoplasmic reticulum of liver cells must coat fats before they are released into the blood, but the fat still builds up, killing cells and impairing function until scar tissue forms, in turn impairing and killing further. The liver can no longer break down nitrogenous wastes, thus resulting in death.

Motor Vehicle Traffic Accidents

According to How we Die, 35 percent of trauma in the United States is caused by automobiles and 7 percent by motorcycles. (10% of trauma is from gunshots and another 10% is from stabbings. Pedestrians suffer 7-8% of the major injuries, and 17% occurs as the result of falls. The other 15% is from industrial accidents, bike accidents, and suicide injuries.)

Explains the book, "On a late summer day in 1899, a sixty-eight-year-old real estate broker, ironically bearing the name Henry Bliss, stepped off a trolley car in New York City and was killed by a passing automobile, thereby acquiring the dubious distinction of becoming our country's first automotive traffic fatality. Since then, almost 3 million people have died of motor vehicle injuries."

The cause of automobile accidents varies, of course, with everything from recklessness to fatigue being a factor. However, the single largest factor is alcohol, playing a role in about half of motor vehicle deaths in the United States.

Deaths from trauma are described as trimodal, that is they are either immediate, early or late. Half of all deaths occur immediately (within a few minutes) as a result of injury to a major blood vessel, the heart or the central nervous system (brain damage and bleeding are each responsible for a third of trauma deaths). Others occur within a few hours as a result of harm to the head, lung, or abdomen or bleeding wihin. Late death occurs days or weeks after the injury, often from complication of infection or lung, kidney or liver failure.