Neutrophils. Flashcards
What are the 2 major phagocytic cells of the innate immune system?
Neutrophils.
Macrophages.
What are monocytes?
Macrophages found in the blood.
What is the most powerful phagocytic cell?
Neutrophils.
How do neutrophils destroy foreign microbes?
They are filled with granules which they use to destroy foreign microbes.
What are the 2 kinds of granules that are found in neutrophils?
Primary granules.
Secondary granules.
What 3 things are found in the primary granules that are released by neutrophils?
Enzymes such as myeloperoxidase.
Lysozyme.
Hydrolases.
What is the function of the myeloperoxidase enzymes that are found in the primary granules of neutrophils?
They are responsible for the oxidative burst which kill microbes.
What is the function of the lysozyme that is found in the primary granules of neutrophils?
It attacks carbohydrates in the cell walls of gram + bacteria.
What is the function of the hydrolases that are found in the primary granules of neutrophils?
They degrade bacteria.
What is the function of defensins?
Peptides designed for killing bacteria.
What 3 things found in the secondary granules of neutrophils?
Lysozyme.
Lactoferrin.
Collagenases.
What is the role of lactoferrin?
It binds to iron as iron is essential for bacterial growth.
If the body restricts the amount of iron available then bacteria cannot grow.
What are the collagenases that are found in the secondary granules of neutrophils?
Specialised enzymes that digest the basement membrane between endothelial cells.
What is usually the first immune cell to turn up at a site of inflammation?
Neutrophils.
Where in the body are neutrophils found?
In the blood.
What determines how many neutrophils are found in the blood?
It is species dependent.
What name is given to all of the neutrophils in the blood?
The circulating pool.
What is neutrophilia?
When the circulating pool is larger than normal, this can be a sign of infection.
What is the marginating pool of neutrophils?
Neutrophils that sit on the endothelium and are ready to invade the tissues should there be a problem.
Where in the body are neutrophils made?
In the bone marrow.
What are the 3 pools of neutrophils that are found in the bone marrow?
The proliferation pool.
The maturation pool.
The storage pool.
What is the lifespan of neutrophils?
Around 5-10 days.
What happens to a neutrophil after they have performed phagocytosis?
They die.
What happens when neutrophils die?
They release PAMPs and DAMPs to attract macrophages which will carry on cleaning up the infection.
Are neutrophils capable of proliferating?
No, all new neutrophils are always made in the bone marrow.
What must happen to the neutrophil population if we have a long term infection?
We must keep producing neutrophils as they do not regenerate.
How many pathogens is a neutrophil capable of killing?
Only 1.
