Diseases and Immunity Flashcards
Give 5 examples of sicknesses and that type they are
Bacteria, Virus or Fungus
- Common cold - Virus
- Chicken pox - Virus
- Athletes foot - Fungus
- Gum disease - Bacteria
- The plague - Bacteria
Def. Pathogen
A disease causing microbe/microorganism (bacteria, virus or fungi)
Def. Transmissable/Infectuous disease
A disease in which the pathogen can be passed from one host to another
What protections does the human body have?
- Eyelids
- Tears (which break down pathogens)
- Skin layer
- Blood clotting
- Stomach acid
- Mucus in lungs and nose
- Cilia in lungs and nose
- White blood cells
What do pathogens do when they get into a host?
They reproduce
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What internal defences does the human body have?
- White blood cells
- Phagocytes to carry out phagocytosis
- Lymphocytes to produce antibodies
Def. Direct contact
Pathogen is passed directly from one host to another by transfer of body fluids such as blood or semen
Def. Indirect Contact
The pathogen leaves the host and is carried some way to another uninfected individual
Def. Vector
An organism that transports a pathogen from one host to another
What are the 3 methods of disease transfer?
- Direct contact
- Indirect contact
- Vectors
What are the bodies mechanical defences?
- Skin
- Eyelids
- Ciliated epithelial cells
- Mucus
What are the bodies chemical defences?
- Acid in stomach
- Tears
- Blood clots
- Phagocytes and Lymphocytes
What are some methods of disease prevetion?
- Hygienic food preperation
- Waste disposal
- Sanitation and personal hygiene
- Quarantine
- Vaccinations
How are air-borne diseases prevented?
Quarantine, personal hygiene, masks
How are water-borne diseases prevented?
Boiling of water, drinking bottled water, hygienic food preperation
How are direct diseases prevented?
- Contraception
- Mosquito nets
- Mosquito spray
How are viruses treated?
- Vaccinations have to be done beforehand
- Only resting will help
How are bacterias treated?
Anti-biotics
How are fungi treated?
Anti-fungal cream
What are the 2 types of white blood cell?
Lymphocytes and Phagocytes
What are the characteristics of Phagocytes?
- Much bigger than the average cell
- Lobed nucleus
- Non-specific (treat all pathogens equally)
How do Phagocytes function?
They Destroy invading pathogens by engulfing them (endocytosis) and then carriyng them in a vacuole, which gets stuck to lysosomes, releasing digestive enzymes. The waste is then disposed out of the cell.
What are the characteristics of lymphocytes?
- Smaller that phagocytes
- Full nucleus
- Specific (Both anti-bodies and anti-toxins are specific to the antigen on a pathogen)
How do lymphocytes function?
- They produce anti-toxins to mitigate the effects of the toxins released by pathogens which make you feel ill
- They produce anti-bodies to agglutinate pathogens together
What is an antigen?
Proteins (which vary in shape) on the surface of microorganisms
Why can the human body not fight an infection immediately effectively if a never encountered before pathogen starts to multiply?
The lymphocytes will not recognise the antigens of the pathogens and will release different anti-bodies until it finds one that works
What are memory cells?
Cells that remain after stopping a pathogen and know the right antibody to release straight away in case it returns.
If a pathogen has mutated, the memory cells will not recognise them
Describe the procedure that the body uses to counter an infection
- A pathogen e.g Bacteria enters the blood and begins to multiply
- Organisms feel ill as the number of bacteria increases and release toxins
- Specific lymphcytes become activated and start to release antibodies
- Lymphocytes clone themselves when they have found the right antibody and produce more of it
- Millions of antibodies are released into the bloodstream
- Antibodies attach to antigens causing them to agglutinate, and destroy them
- Clumps of pathogens are ingested by phagocytes
- Lysosomes the release enzymes to break down the pathogens
Def. Active Immunity
When a person makes their own antibodies after exposure to pathogen (long term)
Def. Passive Immunity
When a person is given ready made antibodies (short term) but no memory cells are made
Give examples of:
- Natural active immunity
- Artificial active immunity
- Natural passive immunity
- Artificial passive immunity
- Natural recovery from a sickness
- Vaccines
- Breastfeeding
- Antivenom injection
What is the difference between active and passive immunity
In passive immunity, antibodies are put into an individual’s body, rather than the body producing them itself like in active immunity so it only lasts a short while.
In which cases is passive immunity more useful than active immunity?
When a quick response to the pathogen is needed or the individuals immune system is too weak
What is the downside of passive immunity compared to active immunity?
The individual won’t have long term protection to the pathogen, as their white blood cells didn’t produce the antibodies themselves. On the other hand, active immunity is long lasting as white blood cells keep producing antibodies.
What is the first stage of vaccination?
Small amounts of a weakened or dead microbe is injected into your body.
It cannot hurt you, but your body thinks it is dangerous.
In some cases, only antigens of the pathogen can be injected
What is the second stage of vaccination?
Your body is tricked into making antibodies. The white blood cells make the correct antibodies for the antigens on the microorganism.
What is the third stage of vaccination?
Antibodies are stored in your body (memory cells) in case you are attacked by the same microorganism again.
Your body responds far more quickly next time, before the pathogen can reproduce.
What are the 3 problems with immune response?
- Autoimmune response
- Allergies
- Transplant rejection
Describe how autoimmune response can be a problem with the immune system
The body produces antibodies that destroy its own cells
e.g. Type I diabetes means the cells that produce insulin are destroyed
Describe how allergies can be a problem with the immune system
and how are they treated?
The body over reacts to certain substances causing swelling and tissue damage e.g. hay fever.
Antihistamines are drugs to reduce the immune response
Describe how transplant rejection can be a problem with the immune system
and how is this problem overcome?
Lymphocytes recognise antigens on donor organs and slowly produce antibodies against it.
Immunosuppressant drugs used to slow down immune response.
How is Cholera transmitted?
- Waste matter
- Vectors e.g. flies
- Water
- Food
- People
How is Cholera spread prevented?
- Washing hands
- Cooking of food (Hygeinic food preparation)
- Boiling water/Chlorinating water
- Building latrines (far inland to not contaminate the water supply) (i.e Waste disposal)
- Sewage treatment
What are the treatments to Cholera?
- Oral hydration (salt, suger & safe water, the substances lost to Cholera in the first place)
- Antibiotics
Where does Vibrio Cholerae thrive and reproduce?
The small intestine
a.k.a The gut
What is the aim of the cholera bacterium?
To thrive and reproduce safely
THEY DO NOT INTENTIONALLY CAUSE HARM TO THE BODY OF THE HOST
How does Cholera make you sick?
- The Cholera bacterium produces the Cholera toxin
- The toxin attaches itself to receptors on the cells of the epithelium (microvilli)
- This causes Ions such as Chloride to exit the villi and go back into the small intestine, so the concentration of chloride ions in the small intestine increases
- The water potential decreases in the small intestine
- This causes osmosis to occur, where water goes down the water potential gradient into the small intestine from the microvilli
- The water and the ions are lost via vomit and diarrhoea
What type of ion is principally released into the bloodstream due to the Cholera toxin?
Chloride Ion
