1st Line of Defence
What is the main physical barrier of the body that prevents pathogens from entering?
Skin
What is the name of the general, non-specific white blood cells that engulf pathogens?
Phagocytosis
What type of white blood cell is responsible for producing antibodies?
Plasma Cells
What is a pathogen?
Disease causing organism
What is a vaccine?
A substance that stimulates the immune system to produce memory cells without causing illness.
Which body fluid contains what that break down bacteria, and is found in tears and saliva?
Lysozome
Outline the process of inflammation
Swelling, redness, heat, vasodilation
What is the name of the molecules on the surface of pathogens that the immune system recognises?
Antigens
Name two types of pathogens.
Bacteria, Virus, Fungi, Parasites, Protozoa, Prion
What are antigens?
(Foreign protein molecules that trigger an immune response)
How does stomach acid contribute to the first line of defence?
It kills ingested pathogens due to low pH
What chemical do damaged cells release to trigger inflammation?
Histamine
What do antibodies do to help fight pathogens?
They bind to antigens to neutralise or mark them for destruction
Why are viruses not considered living organisms?
They cannot reproduce without a host cell.
Define antibodies.
(Proteins made by B cells that specifically bind to antigens)
What are cilia.
Tiny microscopic hairs that move trapped pathogens.
Explain the process of phagocytosis in the second line of defence.
Phagocytes engulf and digest foreign particles or pathogens using enzymes
How does a helper T cell contribute to the humoral response?
Activates B cells to produce specific antibodies
What is the difference between a bacteria and a protozon?
Bacteria is prokaryotic, protozoan is eukaryotic
What does “non-specific” mean in terms of immune defence?
It targets any pathogen, not just one specific type
Explain the process of apoptosis
When infected cells and neighbouring cells are marked for cell destruction.
Identify the physical and chemical changes that occur in the 2nd line of defence. (min 2 of each)
chemical - pryogen release, histamine release
physical - vasodilation, increased temp, increased WBC
Outline the link between the 2nd line of defence and the 3rd line of defence.
WBC from 2nd line present the antigens to the helper T cells in the lymph nodes to activate the B cells.
What is the difference between plasma B cells and memory B cells?
Plasma B cells produce antibodies immediately; memory B cells remain to provide long-term immunity
What is the purpose of memory cells in the immune system?
To “remember” a pathogen and trigger a faster response next time