ICS - PATHOLOGY Flashcards
Define inflammation
TEst
It’s hard to define, but its a reaction to a tissue injury or infection.
Involves cells such as neutrophils and macrophages
It is not a disease but instead usually a manifestation of the disease
How is inflammation classified?
Acute or chronic.
Outline qualities of acute inflammation. give an example
Sudden onset
Short duration
Usually resolves
It is the intial and short lived tissue reactions that occur due to injury
Appendicitis is an example
Outline qualities of chronic inflammation.
Slow onset or comes after acute inflammation
Long duration
May never resolve
When is inflammation good?
It is able to destroy invading microorganisms
Walling off of an abscess cavity can prevent the spread of infection.
When is inflammation bad?
Bad in autoimmunity
Also bad when it over-reacts to the stimulus.
Can cause diesase - eg an abscess in the brain will act as a space pccupying lesion and COMPRESS VITAL STRUCTURES
Fibrosis from chronic inflammation may disort tissues and permanently alter function
Name some cells that are involved in inflammation.
Neurtophils Polymorphs
Macrophages
Endothelial Cells
Lymphocytes
Fibrolasts
Outline what Neutrophils Polymorphs are.
THEY ARE GRANUOLCYTES!!!!
Short lived cells, that are FIRST ON THE SCENE OF ACUTE INFLAMMATION
They contain cytoplasmic granules that are full of enzymes that kill bacteria
They normally die at the scene of inflammation
They RELEASE CHEMICALS that attract other inflammatory cells eg Macrophages.
Outline what Macrophages are
LONG LIVED CELLS, (weeks to months)
They have PHAGOCYTIC PROPERITES
They INGEST bacteria and debris, and may carry them away
present antigen to lymphocytes
How long to Lymphocytes live for? What do they do? What is special about them?
They are long lived cells (YEARS)
They produce chemicals which attract in other inflammatory cells
They have an IMMUNOLOGICAL MEMORY for past infections and anitgens
What are endothelial cells?
They line the capillary blood vessels in areas of inflammation
What do endothelial cells do in inflammation? How do they help inflammatory cells? 3
They BECOME STICKY in areas of inflammation so inflammatory cells can adhere to them
They BECOME POROUS to allow for inflammatory cells to pass into tissues
The GROW into areas of damage to form new capillary vessels
Are fibrobalsts long or short lived? What do they do?
They are long lived. They form collagen in areas of chronic inflammation
What are the 5 main features of Acute Inflammation?
- Rubor (Redness)
- Tumour (Swelling
- Calor (Heat)
- Dolar (Pain)
- Functio Laesa (Loss of function)
What happens to vessel walls in acute inflammation?
Precapillary sphincters open (which are regulated by arteriolar walls)
thereby increasing the blood flow
thorough the capillaries contributing to redness and heat
Endothelial cell walls separate, as a response to mediators.
Inflammation can be triggered by internal or external factors- give examples of external factors
External are either
Non microbial (eg Allergens, Irritants, Toxic Compounds)
Or Microbial Factors
Outline two main microbial factors
What are PAMPs?
Virulence Factors - Help pathogens colonise tissues and cause infections
Pathogenic associated molecular Patterns (PAMPs) = General molecular features common to many types of pathogen - the body recognises to trigger inflammaroty response
Outline what DAMPs Are
DAMPs are Damage Associated Molecular Patterns, and are INTRACELLULAR PROTEINS that get released when a cells plasma membrane is injured, or when the cell dies - THEY TRIGGER INFLAMMATION, AN INTERNAL FACTOR
the inflammatory process: Name 3 things Macrophages and Mast Cells release, and what does it do to blood vessels?
1 Macrophage and Mast cells release inflammatory mediators like Histamine, Serotonin, Cytokines, and Eicosanoids like prostaglandins.
- These mediators act on the endothelial cell wall, causing the cells to separate.
- These mediators cause the capillaries to swell/dilate, and the separation of the cells lead to INCREASED VASCULAR PERMEABILITY
Nitric oxide also makes the capillaries more permeable.
Macrophages will start to eat pathogens
What happens to the hydrostatic pressure in capillaries during acute inflammation? why is this? What happens as a consequence?
Capillary hydrostatic pressure increased. As mediators cause blood vessels to SWELL/VASODILATE and the cells in the capillary endothelium separate, increasing VASCULAR PERMEABILITY
As a consequence, plasma proteins leave the capillary.
Define Exudation. What is fluid exudate
The net escape of protein rich fluid into the exravascular space.
This protein rich fluid is called Fluid exudate.
What are the 5 main causes of acute inflammation?
Microbial Infections
Irritant and corrosive chemicals
Physical agents
Tissue necrosis
Hypersensitivity reactions
MIPTH
Briefly outline how microbial infections cause acute inflammation
Bacteria release exotoxins, which are chemicals that specifically iniate inflammation,
or ENDOTOXINS, associated with their cell walls
What are the 3 key things that accumulate in extracellular spaces in acute inflammation?
oedema fluid (exudate), fibrin and neutrophil polymorphs
accumulate in the extracellular spaces
Fibrin is deposited on the extravascular tissues, hence they are said to be covered in fibrinous exudate