Chapter 10 - Diseases and immunity Flashcards
What is a pathogen?
A pathogen is a disease-causing organism.
What is a transmissible disease?
A transmissible disease is a disease in which the pathogen can be passed from one host to another.
How can pathogens be transmitted?
Pathogens can be transmitted through direct contact of bodily fluids such as blood or semen (e.g. HIV, gonorrhoea, hepatitis B and hepatitis C). Pathogens can also be transmitted through indirect contact including contaminated surfaces, food, animals and air.
What are some examples of diseases spread by certain methods of transmission?
What are mechanical barriers?
Mechanical barriers are structures that make it difficult for pathogens to get past them and into the body. Skin and hairs in the nose are examples of mechanical barriers.
How does skin act as a mechanical barrier?
Skin covers almost all parts of your body to prevent infection from pathogens. If it is cut or grazed, it immediately begins to heal itself, often by forming a scab.
How do hairs in the nose act as a mechanical barrier?
Hairs in the nose make it difficult for pathogens to get past them further up the nose so they are not inhaled into the lungs.
What are chemical barriers?
Chemical barriers are substances produced by the body cells that trap or kill pathogens before they can get further into the body and cause disease. Mucus and stomach acid are examples of chemical barriers.
How does mucus act as a chemical barrier?
Mucus is made in various places in the body, pathogens get trapped in the mucus and can then be removed from the body (by coughing, blowing the nose or swallowing).
How does stomach acid act as a chemical barrier?
Stomach acid contains hydrochloric acid which is strong enough to kill any pathogens that have been caught in mucus in the airways and then swallowed or have been consumer in food or water.
How can different cells prevent pathogens from reaching the body?
Cells are different types of white blood cells that work to prevent pathogens reaching areas of the body they can replicate in. By phagocytosis which is when phagocytes engulf and digest pathogenic cells. By producing antibodies which clump pathogenic cells together so they can’t move as easily (known as agglutination) and releasing chemicals that signal to other cells that they must be destroyed.
How can people prevent the spread of disease?
The simplest way to prevent the spread of disease is to stop pathogens from spreading. This can be done by using a clean water supply, having hygienic food preparation, good personal hygiene, proper waste disposal or sewage treatment.
What are some examples of hygienic food preparation?
Keep food cold so bacteria and fungi can’t reproduce.
Prepare food hygienically to avoid contamination from pathogens by washing hands with soap and cleaning work surfaces with products such as bleach to kill pathogens.
Cook food well (long enough at high temperature to kill bacteria and fungi.
Cover food to prevent flies landing on it before eating.
Use separate chopping boards and utensils for cutting uncooked meat,
Wash hands after using the bathroom before handling food.
What are some examples of good personal hygiene?
Washing with soap removes substances which trap pathogens as well as pathogens themselves from the skin.
Use tissues to catch sneezes and coughs.
Dispose of used tissues as soon as possible as pathogens can still be alive.
Wash hands after using the bathroom.
What are some examples of waste disposal?
Waste food is a food source for flies that can act as vectors for transmissible diseases and so should be disposed of in a sealed container.
Rubbish bins should be covered and removed to landfill for disposal or burning regularly.
All rubbish should be stored before collection away from human habitation.
