Flashcards in 3.1 Immune System Deck (32):
Why do humans have an immune system?
To attack and destroy invaders that enter the body.
Our immune system has 2 lines of defence. Name them.
1. First line of defence
2. Second line of defence
Describe the 2 parts that make up the first line of defence.
Skin and the linings of the body's internal systems.
mucus, cilia, stomach lining etc
Describe the 2 parts that make up the second line of defence.
The second line has 2 parts
1. Innate = built - in response. The innate response is a quick and general response. Inflammation, blood/fluid rushes to the area. Macrophages engulf invaders indiscriminately. Redness, swelling, fever.
2. Acquired = slow and specific response, antibody production targets specific invaders and then invaders are remembered. Main players are B cells and T-cells
What is a pathogen?
A pathogen is a disease-causing invader - makes you sick
What is an infectious disease?
A disease caused when an organism enters the body.
What are the 4 ways to transmit infectious diseases?
1. Direct contact
2. Indirect contact
3. Water and food
4. Animal bites
Give an example of each of the 4 ways to transmit an infectious disease.
1. Direct contact - shaking hands or sharing drinking containers or mixing body fluids with an infected person
2. Indirect contact - being near an infected person who sneezes without covering his or her mouth.
3. Water and food -eating foods or drinking water that are infected
4. Animal bites - being bitten by an animal carrying the rabies virus
Name parts of the body that belong to the first line of defence.
Skin, stomach acid, mucus, cilia tears, oil and sweat on skin
Describe the Innate Immune Response.
- quick and general
- responds in the same way to every invader
-first action is a flow of fluid, cells to site of infection
- this causes swelling and redness
-# and type of white blood cells increase in the area of inflammation
What is a phagocyte?
a type of white blood cells, the biggest and baddest is the macrophage which engulfs and kills invaders
What is the role of a phagocyte?
To fight infection by swallowing them
Describe the Acquired Immune Response in general.
This is a highly specific attack on a pathogen OR antigen. Your body can do this in 2 ways:
1. B cells in action
2. T cells in action
Describe the 2 ways your body can mount an attack on an invader (Acquired Immune Response)
1. B cells - they recognize antigens and then they make antibodies, specific to antigens.
- Antibodies can either prevent pathogen from infecting cells OR the mark pathogen for destruction. At the same time, similar B cells are made to fight other antigens in body.
2. T cells - starts when pathogen or antigen is inside body. White blood cell recognizes invader and signals for T cells.
- One type of T cell = helper T cell - it recognizes invader and activates the B cells.
- B cells make antibodies which destroy
- when the attack is over, some antibodies
remain in body to protect in the future.
- Another T cell = killer T cell - can work by themselves to destroy invaders or with the other cells.
What is an antigen?
A substance your body cannot recognize. Antigens are NON-LIVING particles or substance.
Anything your body recognizes as foreign.
Example: virus, splinter
What is an antibody?
Specific proteins that fight specific invaders.
Tags for invaders so they can be destroyed.
What is active immunity?
When your body remembers which antibodies should be used to attack a pathogen that has infected it before.
The antibodies are stored on B cells called memory cells that can be reactivated if the antigen or pathogen reappears.
What did Joseph Lister do?
Learned about washing hands and sterilize their tools - aseptic surgery
What did Mary Montagu do?
Put pus in a cut and created immunity to sell pox (in India)
What did Edward Jenner do?
Infected an 8 year old with cow pox to give him immunity to small pox
what is a leukocytes?
a white blood cell
what are the two types of leukocytes?
phagocytes and lymphocytes
what are lymphocytes?
T cells and B cells which kill pathogens with the help of helper T cells and produce antibodies against pathogens
What are memory B cells?
help remember specific antigens for later
What are helper T cells?
Help B cells to kill pathogens
What is a cytotoxic/killer T cell?
kills pathogens after it has infected a body cell by destroying the whole cell
what is an allergy?
over-sensitive reaction to something -releases histamine which leads to allergy symptoms
what is an allergen?
foreign substance that causes an allergy
what is an anaphylactic reaction?
a severe allergic reaction
what is immunity?
resistance to a pathogen
What are the four ways a pathogen can be transmitted?
1. direct contact
2. indirect contact
3. ingestion - food or water
4. animal or insect bite