Week 1(1) Acute Inflammation Flashcards
What are some examples that can potentially cause the body injury?
*Trauma *Infection *Heat/Cold *Chemical *Radiation *Infarction
How does the body protect itself from injury BEFORE it occurs?
*neural reflexes *fear/fight flight responses *protection against infection - skin barrier -enzymes in saliva - acid in stomach - bacteria in gut - mucus and cilia in gut - marophages in airway
How does the body protect itself from injury AFTER it happens?
= INFLAMJMATIOn
What should be happening in the histology slides at the following stages
a. Inflammation
b. Demolition
c. Repair
a. Many NEUTROPHILS are present
b. Many MACROPHAGES are present
c. Many BLOOD VESSELS are developing
Note- See Page 4 Lecture 1
What is Inflammation?
- The protective response of living vascularised tissues to injury
- to eradicate cause and consequences of injury
- repair or healing (repair=cell regeneration or scars)
Name the IMPORTANT FEATURES of Inflammation
- blood components: cells, proteins
- blood vessels
- chemical mediators
- cellular and extracellular components of CT
What are the two main types of Inflammation?
Chronic
OR
Acute
Name the main two types of inflammation and the differeces between each type
Acute
- earliest response
- lasts days
- FEATURES = neutrophils, oedematous, exudate, vasodilation, NON-specific
Chronic
- later response
- lasts weeks –> months
-FEATURES = macrophages, lymphocytes, plasma cells, often leads to fibrosis (scarring), specific OR non-specific
What causes ACUTE inflammation?
* Certain infections
* Trauma
*Burns
*Infaction
What does ACUTE inflammation aim to do?
* deliver nutrients, defence cells
*destroy infective agents
*remove debris
Features of ACUTE inflammation
1. Vascular response
2. Exudate
3. Variable tissue necrosis
What are the vascular and cellular responses of acute inflammation?
* Initial dialation of focal blood vessels increasing blood flow, then blood flow SLOWS
* Vessels become LEAKY and PERMEABLE, permitting the passage of water, salts adn small proteins = EXUDATION
*Circulating NEUTROPHILS are attached to damaged areas and adhere to swollen endothelial cells (MARGINATION) and migrate through BM (EMIGRATION) into damaged areas
* Later, macrophages and lymphocytes migrate to damaged areas.
What is Exudate?
Definition - Protein rih fluid and cells that have escaped from blood vessels due to an increase in vascular permeability.
NB - VERY different from transudate
What is the COMPOSITION of exudate?
FLUID: nutrients, immunoglobulins. Circulates through vessels and extracellular space
FIBRIN: a network of fibrin prevents migration of micro-organisms and assists migration of neutrophils and macrophages to damaged areas
NEUTROPHILS: MANY OF THESE
MACROPHAGES: Phagocytic and kill bacteria, assist in repair. Have a more important role in chronic inflammation.
LYMPHOCYTES: more frequently found in CHRONIC inflammation
What are the FUNCTIONS of acute inflammatory exudate?
* Carries proteins, fluid and cells from local blood vessels into the damaged area
* The compenents of teh exudate are able to destroy the infective causative agent
* Break down and remove damaged material
Chemical mediators of inflammation
* may be produced locally by cells at the site of inflammation
* cell-derived mediators
*plasma-dervived mediators
What are the cell-derived mediators of inflammation?
- circulating NEUTROPHILS,
MONOCYTES,
PLATELETS and TISSUE
MAST CELLS
MACROPHAGE
and ENDOTHELIAL cells
are all cellular sources of inflammatory mediators
What are the plasma-dervived mediators of inflammation?
3 Proteins circulating - complement, kinin and coagulation
Complement pathway - once activate complement proteins opsonize patricles e.g. microbes which enhances phagocytosis and destruction
Kinin and coagulation system - Hageman Factor
What are NEUTROPHILS and their role?
* prodcued in bone marrow
* short life span
*chemical mediators attracts them to the area
*actively phagocytose and destroy bacteria
*release free radicals
*release lusosomal enzymes to break down extracellular matrix
How does a neutrophil work?
- Moves along the endothelium (margination)
- Then into tissues (emigration)
- Attracted to damaged area (chemotaxis)
What stimulates the release of Neutrophilia?
Cytokines released from macrophages and neutrophils in an acute inflammatory response circulate in the blood and stimulate increased neutrophil release and increased production of neutrophils in the bone marrow
Macrophages - what are they?
- dervived from blood monoytes
- phagocytic
- assist in repair
- important in chronic inflammation and immunity
What are the physical signs of acute inflammation?
* redness
*heat
*pain
*swelling
Why do we have each of the 4 physical (clinical) effects of acute inflammation?
Redness: due to vessel dilatation and increased blood flow
Heat: due to vessel dilatation adn increased blood flow
Pain: due to pressure effects on nerve endings and chemical factos
Swelloing: due to accumulation of exudate
