Immunity Flashcards
What is the lymphatic system comprised of?
Lymph
Lymph nodes
Lymph vessels
Define lymph fluid
Travels through a system of vessels and baths all body cells allowing them to drain into the vessels
What special feature do lymph vessels have?
They have valves which control a one way motion of fluid
Why does the lymph rely on for movement
Muscle contraction
What is the relationship between the circulatory system and the lymphatic system?
Joins up at the neck and drains into the blood stream
What is blood composed of
- Red blood cells
- White blood cells
- Platelets
What is another name for white blood cells?
Leukocytes
What is the red of the red blood cell
To transport oxygen around the body
What is the role of the leukocytes
Cells that have specific roles in 2nd and third line of defence
Explain all three lines of defence
- Barrier to prevent the entry of the pathogens into the body
- Non-specific immune response: try to destroy every pathogen that is encountered
- Specific immune response only attack specific pathogens
What can the specific and non-specific also be known as?
Adapative and Inate
Explain the first line of defence
The first round of defence mechanism that they meet is a non-specific response which is a range of chemical and physical barriers.
NO MEMORY of the pathogen is formed after the invasion
List the chemical barriers for the first line of defence
-Acids
-Enzymes
-Mucous Membrane: traps microorganisms
-Tears
Sebum
List the physical barriers for the first line of defence
- intact skin: waterproof layer
- cilia: filter air
- nasal hairs: filter air
- hair
- ear wax: traps pathogens
- eyelashses
What are “non-self” molecules
Foregin cells or particles
What are self molecules
Molecules that belong to that particular organism
Define Antigen
A foreign substance that causes the immune system to make a specific immune response
Where are MHC markers founds?
proteins that are found on the surface of the cells membrane
Are all MHC markers the same
Determined by genes therefore each individual has their own MHC markers
What do MHC markers allow?
The body to recognise that the cell belongs to itself
What are the two classes of MHC markers and explain them
Class 1 MHC- Found on all body cells that have a nucleus
Class II MHC- Located on antigen presenting white blood cell: B and T lymphocytes
Where do all blood cells come from?
Bone marrow of the long bones in the body
What are all blood cells derived from?
Stem Cells
What is the one group of cells that do not mature in the bone marrow?
T cells leave the bone marrow and mature in the thymus
Is there any memory pathogen formed in the second line of defence?
NO
Define phagocytes
They are white blood cells that move to the point of pathogen entry and are formed in the bone marrow.
Where are phagocytes located?
Normally will move freely through the lymhatic and circulatory system, but will leave in order to track down pathogens
How do phagocytes get rid of the pathogen?
They engulf the pathogens via endocytosis and then will digest the pathogen
Explain a macrophage
They have a long life span and work on various agents
-They detect and destroy by following the chemical trail of the microbe
What if the pathogen is too large for the macrophage to destroy it?
Many phagocytes attach to the pathogen
What happens when a macrophage is injesting a pathogen?
Will display the antigens fragments on its own cell surface in order to activate other parts of the immune system
Explain neutrophils
Most common type of white blood cell, live a short live span and can squeeze in between cells
Explain eosinophils
Secrete enzymes to make holes
Explain Basophils
Secrete histamines causing inflammation
Explain Natural Killer Cells
They attack and kill viral-infected cells by attacking their cell membranes and causing them to lyse
Explain complement proteins
Group of proteins that assist phagocytes in recognising pathogens
Where are complement proteins found?
They continually circulate in the blood
Where are complement proteins secreted from?
Macrophages
When do complement proteins become activated?
When encountering a foreign body and activating one causes another to be activated (domino effect)
How do complement proteins function?
Attach to antibodies on the invading micro-organism and act as flags making the pathogen more identifiable and attracting more phagocytes to it
What do complement proteins do when they come in contact with bacteria and fungi?
They lyse the cell causing their substances to leak out.