why is nicotine bad for the body
The acute hemodynamic effects of cigarette smoking or smokeless tobacco are mediated primarily by the sympathomimetic action. The intensity of its hemodynamic effect is greater with rapid nicotine delivery. [
] Nicotine causes catecholamine release both locally and systemically leading to an increase in heart rate, blood pressure and cardiac contractility. It reduces blood flow in cutaneous and coronary vessels; and increases blood flow in the skeletal muscles. Due to restricted myocardial oxygen delivery there is reduced cardiac work. In a study, chewing a low dose (4 mg) of nicotine gum by healthy nonsmokers blunted the increase in coronary blood flow that occurs with increased heart rate produced by cardiac pacing. [ ] Thus, persistent stimulation by nicotine can contribute to Coronary Vascular Disease by producing acute myocardial ischemia. In the presence of coronary disease, myocardial dysfunction can be worsened. In a placebo-controlled experiment that produced transient ischemia in anesthetized dogs myocardial dysfunction was produced at doses, that did not alter heart rate, blood pressure, or blood flow or myocyte necrosis. [ Nicotine alters the structural and functional characteristics of vascular smooth muscle and endothelial cells. [ ] It enhances release of the basic fibroblast growth factor and inhibits production of transforming growth factor- 1. [ ] These effects lead to increased DNA synthesis, mitogenic activity, endothelial proliferation and increases atherosclerotic plaque formation. [ ] Neovascularization stimulated by nicotine can help progression of atherosclerotic plaques. [ ] These effects lead to myointimal thickening and atherogenic and ischemic changes, increasing the incidence of hypertension and cardiovascular disorders.
A study on dogs demonstrated the deleterious effects of nicotine on the heart. [ Nicotinic acetylcholine receptor's actions on vascular smooth muscle proliferation and plaque neovascularization increases the risk of peripheral arterial disorders. In a murine model of hind limb ischemia, short-term exposure to nicotine paradoxically increased capillary density and improved regional blood flow in the ischemic hind limb. [ ] However, long-term exposure to nicotine for 16 weeks (about one-third of the life span of a mouse) before induction of ischemia obliterated angiogenic response to nicotine. [ Health effects of nicotine are substantial.
Smoking cigarettes, cigars or pipes leads to development of health problems like cancer, emphysema, heart disease. Pregnant women who smoke put their child at risk. Since 1964, 28 Surgeon General's reports on smoking and health have concluded that nicotine health risks are real and tobacco use is the single most avoidable cause of disease, disability, and death in the United States. Yet, some people still ignore the dangers of nicotine. In 1988, the Surgeon General concluded that cigarettes and other forms of tobacco, such as cigars, pipe tobacco, and chewing tobacco, are addictive and that nicotine is the drug in tobacco that causes addiction (read about: ). Nicotine provides an almost immediate "kick" because it causes a discharge of epinephrine from the adrenal cortex. This stimulates the central nervous system and endocrine glands, which causes a sudden release of glucose. Stimulation is then followed by depression and fatigue, leading the user to seek more nicotine. Read more comprehensive information on. Nicotine is absorbed readily from tobacco smoke in the lungs, and it does not matter whether the tobacco smoke is from cigarettes, cigars, or pipes.
Nicotine also is absorbed readily when tobacco is chewed. With regular use of tobacco, levels of nicotine accumulate in the body during the day and persist overnight. One of the dangers of nicotine is that daily smokers or chewers are exposed to the effects of nicotine for 24 hours each day. Adolescents who chew tobacco are more likely than nonusers to eventually become cigarette smokers. Addiction to nicotine results in when a person tries to. For example, a study found that when chronic smokers were deprived of cigarettes for 24 hours, they had increased anger, hostility, and aggression, and loss of social cooperation. Persons suffering from nicotine withdrawal also take longer to regain emotional equilibrium following stress. During periods of abstinence and/or craving, smokers have shown impairment across a wide range of psychomotor and cognitive functions, such as language comprehension. Women who smoke generally have earlier menopause. Pregnant women who smoke cigarettes run an increased risk of having stillborn or premature infants or infants with low birth weight.
Children of women who smoked while pregnant have an increased risk for developing conduct disorders. National studies of nicotine health risks in mothers and daughters have also found that maternal smoking during pregnancy increased the probability that female children would smoke and would persist in smoking. In addition to nicotine, cigarette smoke is primarily composed of a dozen gases (mainly carbon monoxide) and tar. The tar in a cigarette, which varies from about 15 mg for a regular cigarette to 7 mg in a low-tar cigarette, exposes the user to an increased risk of lung cancer, emphysema, and bronchial disorders. The carbon monoxide in tobacco smoke increases the chance of cardiovascular diseases. The Environmental Protection Agency has concluded that secondhand smoke causes lung cancer in adults and greatly increases the risk of respiratory illnesses in children and sudden infant death. Sources: NSDUH (formerly known as the National Household Survey on Drug Abuse) is an annual survey of Americans age 12 and older conducted by the Substance Abuse and Mental Health Services Administration.
- Views: 70
why does cigarette smoke give me a headache
why does chewing tobacco make you sick
why does heart beat faster during exercise
why do we breathe more deeply when we exercise
why is there st elevation in myocardial infarction
why do we breathe more when we exercise
why e cigs are bad for you