UNIT 4 7B: Second Line of defence Flashcards
Inflammatory response
heat, pain, redness, swelling and loss of function as part of the innate immune response to harmful stimuli
Mast Cell
White blood cell involved in inflammatory response, releasing histamine, triggering inflammation
Histamine
Compound released by cells to start an inflammatory response
Macrophage
White blood cell that carries out phagocytosis and may act as an antigen-presenting cell,
releases cytokines to attract more immune cells to the area of infection
Cytokines
Compounds released by cells as chemical signals to other cells
Neutrophil
White blood cell that carries out phagocytosis and kills pathogens with defensins
Dendritic cell
White blood cell with many folds in its membrane, carries out phagocytosis and acts as antigen-presenting cell to the adaptive immune system
Natural Killer Cell
Part of the innate/non specific response (2nd line of defence), that recognises damaged or missing MHC 1 markers on a eukaryotic (host) cell
Releases perforin
Perforin
A protein that kills cells by making holes in their plasma membranes
Eosinophil
White blood cell that targets parasites
Phagocytosis
A type of endocytosis in which a solid substance enters a cell via vesicle mediated transport
Phagosome
A vesicle that engulfs a pathogen during phagocytosis
Antigen-presenting cell
A specific type of white blood cell that uses phagocytosis to engulf a pathogen
Apoptosis
Death and disintegration of a cell through a controlled process
Lysis
Breakdown of the cell membrane
Description/function of complement proteins
-Circulate in the blood
-Can cause lysis by puncturing the pathogen’s plasma membrane
-Coat pathogens to make them more identifiable for phagocytes and to reduce the pathogen’s mobility
Description of Cytokines
Signalling molecule of the immune system
Released by immune cells and acts on other specific immune cells (lymphocytes)
to activate further adaptive immune responses
Examples of Cytokines
Interleukins and interferons
Interferon
A type of cytokine released by an infected host cell that defends against further viral infections
Attracts NK cells to assist in killing virus-infected host cells
Histamine
A signalling molecules released by mast cells that initiates the inflammatory response
Vasodilation
The widening of a blood vessel (especially capilalries), to increase blood flow
Key components of the inflammatory response (CCMMVN)
-Cytokines
-Complement proteins
-Mast cells
-Macrophages
-Vasodilation
-Neutrophils
Fever
A rise in body temperature caused by infection, can be caused by cytokines from the inflammatory response
How is an increase in body temperature during vasodilation beneficial to the immune response
Most bacteria and viruses prefer a lower body temperature in order to replicate more efficiently, while the immune cells perform better at slightly higher temperatures
Key steps of the inflammatory response
- Mast cells release histamine
- Histamine induces vasodilation, resulting in an increase in blood vessel permeability, blood flow, heat, redness and swelling
3.Phagocytes(such as neutrophils, macrophages) leave the blood and enter the infected tissue - phagocytes are attracted by histamines and engulf and destroy the pathogen
- Macrophages secrete interleukins, which leads to fever
Key steps of phagocytosis
- Phagocyte engulfs a pathogen via endocytosis
- Vesicle surrounding the pathogen forms a phagosome
3.Lysosomes containing lysozyme attach to the phagosome and release their content to digest the pathogen - Debris is released via exocytosis and antigens may be presented on an MHC 2 markerif the phagocyte is acting as an APC
Which phagocyte is first to the site of infection
Neutrophils
Aims of the inflammatory response
to destroy the cause and products of an infection
to confine the infection to a small area
To increase the rate at which damaged cells are repaired or replaced
What is pus composed of
living and dead white blood cells and pathogens
Similarities between natural killer cells and cytotoxic T cells
Both target:
Virus infected host cells
transplanted tissue/organs
both release perforin which punctures holes in infected cell, lysing the cell
