Biology 1 causes of disease

1.1 - Pathogens

1.2 - Data And Disease

1.3 - Lifestyle And Health

Micro organism is a single celled organism (bacteria, Virus)

Pathogens are disease causing micro organisms (bacteria, Virus, fungi)

Disease is a descriptor for symptoms either physical, mental or both

To be considered a pathogen must:    -gain entry to the host

                                                            -colonise the tissue

                                                            -Resist defences

                                                            -cause damage to host tissue

If pathogen is in host and colonises tissue = Infection, If symptoms are visible = Disease

Pathogen transferred from one person to another= transmission

Get into body by body’s interfaces with environment:-breaks in skin

                                                                                    -gas exchange system

                                                                                    -digestive system

There are a number of defences:        -mucous layer in gas exchange surfaces

                                                            -production of enzymes to break down

                                                              pathogens

                                                            -production of stomach acid which kills 

                                                             Microorganisms

Pathogens affect the body by: -damaging host tissues by inhibiting D/RNA synthesis

                                              breaking down cell membrane    

                                            -produce toxins

Correlation = change in one of two variables is reflected in the other variable

Causal relationship = the change in one factor is certainly due to the change in another Factor

 Is it a coincidence or is there a link

 Looking critically

•  Has the right factor been measured and have the correct questions been asked
• How was the data gathered, were the methods reliable, was the right apparatus used?
• Do those collecting the data have a vested interest in the outcome of the research
• Has the study been repeated with the same results and conclusions by other people?
• Are there still unanswered questions?

Risk = “A measure of probability that damage will occur to health as a result of a given hazard”

Aspects of risk are: The probability that a hazardous event will occur

                                The consequences of that hazardous event

Risk measured as percentage (0-100)

Risk needs a timescale

There can be multiple factors that influence risk level

 Cancer risk factors:

• Smoking
• Diet
• Obesity
• Physical activity
• UV exposure

 CHD risk factors:

• Smoking
• High blood pressure
• Blood cholesterol levels
• BMI
• Diet
• Physical activity