disease Flashcards
(17 cards)
what may disease be caused by?
disease may be caused by pathogenic microorganisms or may reflect the effects of lifestyle
what are three examples of infections pathogens?
infectious pathogens include bacteria, viruses and fungi
when does an infection occur?
an infection occurs if a pathogen gets into the host and colonises its tissue
when does disease occur?
disease occurs when an infection leads to recognisable symptoms in the host
what is transmission?
when a pathogen is transferred from one individual to another
how do microorganisms enter the body and how are they prevented from reaching further?
microbes enter the body by penetrating one of the organism’s interfaces with the environment. these interfaces include the digestive and gas exchange systems.
food and water may carry pathogens into the stomach and intestines via the mouth. however, the stomach produces acid which kills microorganisms.
pathogens may enter the gas-exchange system through the nasal passage and mouth and travel towards the lungs. normally the sticky mucus produced by the epithelial cells lining the respiratory passages trap pathogens and they are removed by wafting movements of the cilia. this prevents most pathogens reaching the gas exchange surface.
how do microorganisms cause disease?
pathogens cause disease in two main ways:
- by damaging host tissues. pathogens entering and reproducing inside cells causes damage.
- by producing toxins.
what can lifestyle effect?
lifestyle can affect human health
what is a risk factor?
a risk factor is anything that increases the chance of getting a disease
what are risk factors associated with coronary heart disease?
smoking, high blood pressure, high blood cholesterol levels, prolonged stress, lack of exercise
what are risk factors associated with lung disease?
smoking, air pollution (eg sulfur dioxide), infections, genetic makeup, occupation (eg working with harmful chemicals/gases, radiation)
how can you reduce the risk of contracting these diseases?
changes in lifestyle are often linked to a reduced risk of contracting these diseases
what are risk factors associated with cancer?
smoking, diet, obesity, sunlight (linked to skin cancer)
what is correlation?
correlation is where a change in one of two variables is reflected by a change in the other variable
what is causation?
causation is a factor which is directly a cause of a disease. this can only be established when scientists have produced compelling experimental evidence to show a particular factor is causing a disease.
what is relative risk?
relative risk is measured by comparing the likelihood of harm occurring in those exposed to a hazard with those who are not exposed to it (eg smokers may be n times more likely to develop lung cancer than non smokers)
key phrase to remember
correlation does not imply causation
