Disease

• White blood cells are part of the immune response that helps fight off pathogens such as bacteria and viruses.
• Inflammation occurs when white blood cells move to an area where there has been tissue damage or injury.
• The immune system is the body's defense against infection, disease, and foreign substances.
• Immunurology memory- our body remembers the last time we were sick and helps us recover faster due to the antibodies and b cells that were left in our body after the first time our cells encountered the pathogen
• Immunosuppressed-immune system is weakened
• Phagocyte-type of white blood cell that destroys pathogens (macrophages and neutrophils)
• Infection- when a pathogen enters our body and causes damage to our cells.
• Our body has three lines of defence. The 1st acts as a barrier to prevent pathogens from entering. The 2nd is our body’s general response to pathogens when they enter. The 3rd is our body’s specific response to pathogens when they enter.
• Barrier defences include skin, mucous membranes, cilia, stomach acid, and tears.
• Physical barriers- stop pathogens from entering by blocking or trapping them.

  Chemical barriers- kill pathogens before they can enter the body
• The second line of defense includes phagocytosis, inflammation, fever, and complement proteins.
• Phagocytosis- engulfing and destroying foreign particles such as bacteria and viruses. Phagocytes are specialised white blood cells that patrol the body looking for invaders. They have receptors on their surfaces that recognise antigens on the surface of pathogens. When they find an invader, they surround it with pseudopodia and form a vacuole around it. This process is called endocytosis. Inside the vacuole, lysosomes fuse with the vacuole releasing digestive enzymes into it. These break down the contents of the vacuole killing the pathogen.
• Phagocytosis - engulfing and destroying pathogens
• Fever – increase in temperature which makes it harder for bacteria to survive and reproduce.
• Types of pathogen include viruses, bacteria, fungi and parasites
• Infectious: when a type of pathogen enters your body and causes disease.

  contagious: when a disease can spread from one person to another
• Examples of bacterial diseases include whooping cough (chronic cough with congestion), Tetanus (fever,high blood pressure,muscle spasms, lock jaw), Typhoid fever (fever, headache, stomach pain, rash and diarrhea)
• Clostridium tetani-causes Tetanus

  -found in low oxygen environment (soil)

  -enter body through puncture wounds

  -once bacteria enters body, bacteria multiplies then releases toxins inside your body

  -preventable with vaccines however require 5 year boosters
• Salmonella enteritis- causes gastroenteritis

  -symptoms include fever, headaches and stomach pain

  -expelled via vomiting and diarrhea

  -cause dehydration

  -can be prevented with good hygiene (washing hands,santizing food preparation surface, using different utensils for raw and cooked food)
• Antibiotics-used to treat bacterial infections

  -kill/prevent growth for bacteria by targeting cell wall or metabolic pathways

  -not effective against other pathogens
• Penicillium-first antibiotic discovered

  -discovered in 1928 by Alexander Fleming
• Bacteria can become resistant to antibiotics usually due to a course of antibiotics not being completed
• Vaccines-allow us to pass on immunity artificially

  -made by dead/inactive pathogens and their proteins which trigger the third line of defence with ought making us too sick

  -because they are injecting some of the disease into our body, this helps our body to react so that when we are actually sick, our body can respond better and quicker
• Viruses- must hijack host cell in order to reproduce

  -non living

  -examples include cold,flu,measles,chicken pox etc

  -have surface cells which are perceived as harmless which leads to cells being tricked into accepting the virus. Once inside, virus hijacks host cell into producing bad parts which make up more viruses
• Rhinovirus-causes colds

  -sneeze contains thousands of viral particles which could cause an infection
• Ways to reduce a cold

  -cover mouth when sneezing and coughing

  -frequent hand washing

  -not sharing items

  -avoid close contact with sick individuals

  -quarantine when sick
• influenza-causes cold

  -symptoms include high fever and body aches
• Measles- red rash and in some cases hearing and brain damage
• Chicken pox-begins with runny nose and fever

  -other symptoms include ruitchy red blusters which can cause permanent scaring and secondary bacterial infections

  -can resurface to shingles (painful rashes which last a couple weeks)

  -other sicknesses can trigger shingles
• Antibiotics are ineffective against viruses as they don’t have a cell wall
• Fighting viruses 


  -Getting flu shots

  -letting our body fight it of

  -antiviral drugs (prevent viruses from reproducing inside host cell)

  -nano medicine (disguise as a host cell so that the virus gets tricked into hijacking nano medicine. Once virus is inside cell, nano medicine can then disrupt its production and kill it
• Flu-because it is always mutating, new vaccines must be used every year in order to treat these new strains
• Parasite: an organism that lives in or on an organism of another species (its host) and benefits by deriving nutrients at the other's expense
• Plasmodium-single celled protist organism which causes the disease malaria (mosquitos which transfer malaria are located near equator and malaria was eradicated from Australia in 1981)

  -found in some mosquitos saliva

  -when biting human, parasite enters hosts blood stream resulting in infection
• Vectors-an organism which carries and transmits a pathogen from one host to another
• Malaria symptoms include fever, chills, headache, muscle pain, fatigue, vomiting, diarrhea, jaundice, seizures, coma, death
• Preventing Malaria


  -wearing protective clothing

  -wearing insect repellent

  -using mosquito netting

  -removing any free-standing water

  -anti malarial drugs
• Amoebic dysentey-disease causes by water contaminated with pathogenic amoebae

  -when ingested, parasite infects host

  -symptoms include bloody stool, diarrhea, fever

  -rare cases include death (50,000-100,000) per year

  -treated with antibiotics
• Fungi-reproduce by producing spores which then disperse into the environment and can attach to human skin causing infections

  -only small number of them are pathogenic

  -require warm moist environment to grow

  -commonly found in armpits, groin and feet

  -spread by skin to skin contact, sharing towels/clothing/gym equipment ,walking barefooted on contaminated floors
• Tinea-can grow on hair and nails and feeds on dead skin

  -attacks living cells which cause inflammation and itching (turns skin red and forms a red ring around)

  -red rings have also been called ring worm

  -treated with fungicide