Health Issues (AQA GCSE Biology)

Health & Disease

• Health is the state of physical and mental well-being; lots of factors affect the health of an individual

• Diseases, both communicable and non-communicable, are major causes of ill health; ill-health affects not only the sufferer but their family members and the contribution that individual can make to society

  • Ill health can lead to a poorer quality of life or reduced lifespan

  • The cost of an individual being ill - individuals who are sick may not be able to work and may require expensive healthcare (with the cost being attributed to the individual or a healthcare provider such as the NHS in the UK)

• Communicable diseases are caused by microorganisms called pathogens which can spread between individuals or individuals and animals

  • eg. chickenpox, a common childhood disease, is caused by a viral pathogen called the varicella-zoster virus whereas Covid-19 is caused by the SARS-CoV-2 virus

• Non-communicable diseases are not caused by pathogens and their effects on health tend to be longer-lasting; examples are asthma, CHD and most cancers

• Factors including diet, stress and life situations may have a profound effect on both physical and mental health

  • Eating a balanced diet that provides the right amount of energy and nutrients helps maintain good health whereas a poor diet can lead to deficiencies, obesity, diabetes and poor mental health

  • Constantly being under stress can lead to cardiovascular issues (such as high blood pressure, increasing the risk of CHD) and poor mental health

  • Where a person lives and their income can have a profound impact on health - this affects the standard of healthcare that is accessible to them (and what they can afford), what food they buy etc.

Interactions & Disease

• Different types of disease may interact in ways that negatively affect the health of the individual

• Defects in the immune system mean that an individual is more likely to suffer from infectious diseases; individuals infected with HIV eventually end up with reduced numbers of lymphocytes circulating around the body which reduces the ability of the immune system to fight opportunistic infections like pneumonia

• Viruses living in cells can be the trigger for cancers; the HPV virus can infect cells of the cervix in women resulting in cervical cancer developing in some cases, whereas some strains of the hepatitis virus can cause liver cancer

• Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma - these often develop as a result of an overactive immune response

• Severe physical ill health can lead to depression and other mental illness

Disease Incidence: Representing & Calculating