First Line of Defence
What is the function of the first line of defence?
To keep pathogens out of the body
What is the function of the second line of defence?
To destroy pathogens in the body
Identify the 2 main types of lymphocytes
B cells and T cells
Name 3 types of pathogens
Any 3 of viruses, bacteria, protozoa, fungi, prions, macroparasites
The first line of defence is non-specific - true or false?
True
What happens when the second line of defence fails to destroy the pathogen?
White blood cells that recognize specific invaders
What is an antigen?
An antigen is any substance recognised by the body as ‘not self’ that triggers the production of antibodies
White blood cells are made in the liver - true or false?
False - they are made in the bone marrow To protect the body from disease by recognising and destroying pathogens
What happens if the first line of defence fails to keep pathogens out?
Second line of defence is activated
The second line is an example of 'specific' defence - true or false?
False
What is the role of B cells in the third line of defence?
Produce antibodies
What is the function of the immune system?
To protect the body from disease by recognising and destroying pathogens
Give 2 examples of physical barriers
Intact Skin, eyelashes, nails, nose hairs
What are the 3 parts of the immune response?
1. Phagocytes swallow pathogens
2. Fever
3. Inflammation
How do memory cells help provide immunity to disease?
They remember the antigen (pathogen) and recognise it if it returns, providing a faster stronger response
What is vasodilation?
This is when your blood vessels widen increasing blood flow to the affect areas and allows phagocytes to enter the site of inflammation/injury
Give 2 examples of chemical barriers
sweat, urine, tears, saliva, stomach acid
What are the steps in a fever immune response and how does it help with the body returning back to homeostasis?
Fever is a rise in the body's core temperature above the normal range. (1 mark)
Fever protects against pathogens because some pathogens can't function well at high temperatures. The increased temperature slows or kills the pathogens and makes it easier for the patient's immune system to fight them. (1 mark)
Give an example of a T cell and describe their role in the defence of the body
Helper T cells: give instructions to other cells by producing signals. Each T helper cell only looks out for one type of pathogen.
Killer T cells: These are killer cells. They punch holes in the walls of the pathogen cell so that the contents ooze out.
What the 4 steps when an individual is vaccinated?
1. Vaccine (with inactivated antigen) enters the body
2. B cells produce antibodies (act as weapons) and memory cells (remain in the body as a ‘memory’ of the pathogen)
3. B cells with matching antibodies bind to these antigens
4. If/when the pathogen shows up again, the body already has memory and can produce weapons (antibodies) to attack the virus/disease without showing symptoms