Health and Disease Flashcards
What is health?
A state of mental, physical and social well-being
What is a communicable disease?
A disease that can be passed on from one person to another
What is a non-communicable disease?
A disease that can’t be passed on from one person to another
What is a pathogen?
An organism that causes an infectious disease
What are the different types of pathogen?
- Bacteria
- Protists
- Fungi
- Viruses
What type of pathogen causes cholera, what are the symptoms and how is it spread?
Cholera is caused by bacteria, the symptoms are watery, pale coloured diarrhoea often in large amounts, cholera is spread when people intake food or water containing the cholera bacterium
What type of pathogen causes malaria, what are the symptoms and how is it spread?
Malaria is caused by protists, the symptoms are fever, weakness, chills and sweating, it is spread via an animal vector
What type of pathogen causes HIV, what are the symptoms and how is it spread?
HIV is caused by a virus, the symptoms are flu-like symptoms when first infected, eventually repeated infections of other disease (often no symptoms are shown for a long time, it is spread by bodily fluids
What type of pathogen causes TB, what are the symptoms and how is it spread?
TB is caused by bacteria, the symptoms are lung damage, weight loss, fever, sweats, it’s spread by airborne mucus
What type of pathogen causes ebola, what are the symptoms and how is it spread?
Ebola is caused by a virus, the symptoms are internal bleeding and fever, headaches, muscle pain, vomiting and diarrhoea, it is spread by bodily fluids
What causes stomach ulcers and what are the symptoms?
Caused by bacteria, the symptoms are inflammation in the stomach and bleeding in the stomach
What causes ash die-back and what are the symptoms?
Caused by a fungus, the symptoms are leaf loss, bark damage and dieback on top of the tree
Describe the stages of a virus’ lifecycle (lytic cycle)
- Virus attaches to host cell
- Virus injects its DNA or RNA into the cell
- Virus RNA or DNA copies itself and causes new virus proteins to be made, using the organelles in the host cell
- The DNA or RNA and the virus proteins are packaged together to make new viruses, these are released from the cell, destroying the cell in the process
Describe the stages of a virus’ lifecycle (lysogenic cycle)
- Virus attaches to host cell
- Virus injects its DNA or RNA into the chromosomes of the host cell
- It is now called a provirus
- The provirus replicates with the rest of the host cell DNA every time the host cell divides
- The provirus can stay dormant for a long time like this
- At some stage the provirus will become active and make new viruses that are released from cells, destroying the cell in the in the process (this stage is the same as in the lytic cycle)
What are the common methods of STI transmission?
- Unprotected sex
- Sharing needles
- Transmission from mother to foetus
- Infection from blood products
How can STIs be prevented?
- Condoms
- Sterile needles
- Screening tests on people and blood transfusions
What do physical barriers do against pathogens?
Make it hard for pathogens to enter the body
What do chemical defences do against pathogens?
Kill or make pathogens inactive
What are some examples of chemical defences?
- Lysozyme enzyme found in tears saliva and mucus, digests bacteria cell walls
- HCl found in stomach kills pathogens in food and drink
What are some examples of physical barriers?
- Unbroken skin is too thick for most pathogens to get through
- Sticky mucus in the breathing passages and lungs traps pathogens and cilia moves trapped mucus and pathogens out of the lungs towards the back of the throat where it’s swallowed
What is a lymphocyte?
A type of WBC used to help protect the body against pathogens
How does the immune system work?
- Each pathogen has unique antigens on its surface
- A lymphocyte with the antibody that is specific to that antigen is activated
- The lymphocyte divides many times to produce more identical lymphocytes
- Some of the lymphocytes produce lots of antibodies which stick to the pathogen and destroy it
- Other lymphocytes stay in the blood as memory lymphocytes, they’re ready to respond immediately if the same pathogen returns