Untitled

<aside> 💡 KEY TERM - for revision

</aside>

can help fight an infection by slowing down or killing pathogens | | first line of defence | barriers that prevent pathogens from entering the body skin, saliva, urine and tears are barriers in the first line of defence | | fungus | an organism with complex cells that feeds off a living host | | herd immunity | the protection from infection provided when most of a population is immune

• protects vulnerable and unvaccinated people because of the less likelihood being exposed to infection | | immune system | the body system that prevents and fights disease includes skin, fever and specialised white blood cells | | immunity | the body’s ability to protect itself from infection
• build up immunity to pathogens by fighting of an infection or by being vaccinated | | infection rate | the percentage of unvaccinated people who become infected with a disease | | infectious disease | a medical condition that is caused by a pathogen | | inflammation | painful redness or swelling of part of the body
• occurs when increase blood flow brings white blood cells to fight invading pathogens | | memory cell | a B cell that remains in the bloodstream to recognise pathogens
• provide long-term immunity by responding to infections | | microbe | an organism that is too small to be seen with the naked eye
• include bacteria and some types of fungi | | mucus | a sticky liquid that lines the nose, throat, lungs and intestines | | non-contagious disease | a medical condition that can’t be spread from person to person | | pathogen | a microscopic organism | | phagocyte | a white blood cell that engulfs and destroys pathogens | | physical barrier | a defence that blocks or traps pathogens before they can enter the body skin, mucus and cilia | | second line of defence | general responses to pathogens inside the body fever, inflammation and phagocytes | | third line of defence | responses to specific pathogens inside the body that builds immunity B cells, memory cells and antibodies | | vaccination | a treatment that helps build immunity to an infectious disease
• most are given by injection, some are given by mouth or as a nasal spray | | vaccination rate | percentage of population that is vaccinated against disease | | vaccine | substance that boosts body’s immunity to a specific pathogen
• made of dead or weakened pathogens and cause the body to make new antibodies | | virus | microscopic infectious agent made of genetic material and proteins | | white blood cell | component of blood that fights infections phagocytes, B cells and memory cells |

Pathogens

• three different types of diseases:
  • infectious diseases
    • some are contagious
  • contagious diseases
    • all are infectious
  • non-infectious diseases
    • none are infectious or contagious

pathogenic diseases: caused by organism or agent

pathogen: disease causing agent or organism

• types of pathogens:
  • bacteria
  • virus
  • fungi
  • protozoa
  • prion

Transmission of infectious diseases

person to person

• passing through physical contact, blood, saliva or other body fluids

food-borne

• pathogens live on or in food and enter a host when food is eaten
• poor food-handling, hygiene and cooking increases risk of infection

water-borne

• spread through contaminated water

airborne

• spread through the air, usually in tiny droplets from coughing or sneezing

insect-borne

• spread through insects like mozzies and fleas

Bacteria

characteristics

bacteria: single-celled organisms found in almost every possible environment

• cells reproduce very quickly
• some are helpful, line intestines and skin to prevent bad bacteria to cause infection
• some are pathogens → can cause infection or disease

examples

tetanus

• Clostridium tetani is found in soil
• can’t live in oxygen presence
• passed on by puncture wounds from rusty, dirty objects
• bacteria multiplies deep within wounds
• toxins can causes disease → binds with nerve cells causing the contraction of muscles

typhoid fever

• Salmonella typhi
• passed on by contaminated water supplies or person to person
• prolonged high fever, diarrhoea, headache and pain
• intestinal perforation, kidney failure and peritonitis (type of inflammation in abdominal cavity)