3.1 Immune System Flashcards
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.
- 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
- 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.
- 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?
- Direct contact
- Indirect contact
- Water and food
- Animal bites
Give an example of each of the 4 ways to transmit an infectious disease.
- Direct contact - shaking hands or sharing drinking containers or mixing body fluids with an infected person
- Indirect contact - being near an infected person who sneezes without covering his or her mouth.
- Water and food -eating foods or drinking water that are infected
- 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
(inflammation)
-# 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:
- B cells in action
- T cells in action
Describe the 2 ways your body can mount an attack on an invader (Acquired Immune Response)
- 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. - 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
invader.
- 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
