IF2 Acute inflammation 2 Flashcards
(16 cards)
Name 6 types of exudates
Serous
Necrotising
Catarrhal
Haemorrhagic
Suppurative/purulent
Fibrinous
What is catarrhal exudate?
An exudate with a lot of mucus & desquamated ep. cells
What is fibrinous exudate?
An exudate with a yellow/white fibrous layer due to deposited fibrinogen.
What is suppurative/purulent exudate?
Opaque exudate of varied colour, viscosity & odour.
What is the role of exudate?
The fluid part of the exudate helps to dilute toxins & carry antigens from the site of infection to lymph nodes.
The proteins in the exudate can help with endothelial activation (to form clots), be antibodies for opsonisation of pathogens or make mucus to trap pathogens.
What is the leukocyte extravasation cascade?
1) Mediators induce the endothelium to move pre-formed P selectin/newly synthesised E selectin to the inside of b.v.
2) Leukocyte in the lumen of the b.v gets attracted & tethers to endothelium.
3) P selectin on the endothelium attaches to P selectin receptor on the neutrophil which allows the leukocyte to roll along until it gets activated by chemoattractants and gets stuck in a tight junction.
3) Leukocyte migrates across the endothelium (transmigration) and is chemically attracted to the site of inflammation.
What is neutrophil marginalisation?
When neutrophils that are circulating in the b.v get attracted to the endothelium and attach to it.
What allows neutrophils to adhere to the endothelium?
Mediators make the endothelium sticky
What is the difference between E selectin and P selectin?
If P selectin is used, neutrophil migration is immediate, but if E selectin is used, migration is delayed.
State the functions of neutrophil in acute inflammation.
Phagocytosis of foreign substances
Liquefaction of tissues
Amplification of inflammation
How do neutrophils help to phagocytose foreign substances?
They have scavenger receptors, Fc receptors and complement receptors to recognise opsonins and then engulf the opsonised particle.
How do neutrophils liquefy tissues?
They have granules that contain lysosomal enzymes.
How do neutrophils amplify inflammation?
They can recruit more neutrophils & macrophages by synthesising & releasing leukotrienes, prostaglandins and platelet-activating factor.
State the functions of monocytes & other macrophages in inflammation.
Phagocytosis of foreign substances
Secretion of cytokines
Secretion of toxic factors
Secretion of colony-stimulating factors
Why are monocytes helpful in phagocytosis?
They can phagocytose foreign substances that neutrophils can’t phagocytose because they have more lysosomal enzymes
What is the role of colony-stimulating factors?
They promote the differentiation of newly-recruited immature granulocytes & monocytes
