Body defence Flashcards
Aims of inflammation (3)
- C
- D
- H
- Contain and isolate the injurious stimulus
- Destroy, dilute or wall off the agents and neutralise toxins
- Heal and repair damage caused
Acute inflammation: 5 cardinal signs
- H
- R
- S
- P
- L
- Heat: hyperthermia
- Redness: Hyperaemia
- Swelling: exudate
- Pain: neural damage, chemical mediators
- Loss of function: pain
Acute inflammation: pathogenesis (3)
- Vascular changes
- Cellular events
- Chemical mediators
Vascular changes due to acute inflammation: vascular calibre
(What happens)
- Rapid transient vasoconstriction of arterioles followed by vasodilation
Vascular changes due to acute inflammation: blood flow
- Initial reduction followed by increased blood flow to capillaries
Vascular changes due to acute inflammation: vascular permeability
- Increased permeability of microvasculature
Inflammatory swelling cause:
Oedema due to accumulation of exudate in the interstitium
Exudate properties:
- origin
- Protein content
- Sp.gravity
- Inflammatory extravascular fluid
- Protein rich
- Sp. Gravity > 1.020
Non-inflammatory swelling cause:
Oedema due to accumulation of transudate in the interstitium
Transudate properties:
- Origin
- Protein content
- Sp.Gravity < 1.020
- Ultra filtrate of blood
- Low protein contents
- Sp. Gravity < 1.020
Cellular events due to acute inflammation: transmigration and degranulation of leukocytes
- General mission of leucocytes
- Leucocytes need to move from the circulation to the site injury
Cellular events due to acute inflammation: transmigration and degranulation of leucocytes
- Extravasation
- Endothelial cells and leucocytes express mutually recognising adhesion molecules
Cellular events due to acute inflammation: transmigration and degranulation of leucocytes\
- Migration
- Leucocytes move following concentration gradients of chemicals and infl mediators (chemotaxis)
Cellular events due to acute inflammation: phagocytosis
- General mission of phagocytes
- Phagocytes bind the material to ingest in a multistep process
Cellular events due to acute inflammation: phagocytosis
- Recognition and attachment
- Using its own receptors or to molecules that have been marked by other cells
Cellular events due to acute inflammation: phagocytosis
- Engulfment
- pseudopodia surround the agent producing a vacuole, phagosome
Cellular events due to acute inflammation: phagocytosis
- Killing/degradation
- lysosomal granules fuse with the phagosome activating the destruction by releasing lysozyme, proteases, hydrolase (O2 independent) and toxic superoxides (oxygen dependant)
Chemical mediators of acute inflammation: Plasma mediators
- Form
- System examples (3)
- Need to be activated from precursor form
- Coagulation system
- Kinin system
- Complement system
Plasma mediators: Coagulation system
- Activated by
- Produces (3)
- Tissue damage
- Fibrin
- Thrombin
- Factor Xa
Plasma mediators: coagulation system
- Fibrin role
- Helps contain infections
- Cross links platelets at site of wound
Plasma mediators: coagulation system
- Thrombin role
- increases leukocyte adhesion and fibroblast proliferation
Plasma mediators: coagulation system
- Factor Xa role
- Increases vascular permeability and leucocyte exudation
Plasma mediators: kinin system
- Activation
- End product
- End product role
- Activated by coagulation factor XII
- Produces bradykinin
- Causes vasodilation and triggering pain
Plasma mediators: complement system
- 20 components
- Foreign expression of adhesion molecules on leucocytes