Acute Inflammation Flashcards
What are the 3 aims of inflammation?
To get rid of damaged/ necrotic tissue
To remove microorganisms or foreign material
To set the scene for regeneration or repair of tissues
What are the five cardinal rules of inflammation
Redness, Swelling, Heat Pain and Loss of Function
What are the three components of a rapid response to stimuli?
- Increased blood flow
- Increased vascular permeability
- Leukocyte emigration
What is the stimuli for acute inflammation?
Microorganisms, Necrosis, Hypoxia, Foreign bodies, Hypersensitivity reactions
What is the release of excess fluid into tissue for body cavities called?
oedema
What are some microorganisms that cause acute inflammation?
Parasites, fungi, bacteria, viruses, microbial toxins
What is the release of fluid and cells from circulation called?
exudation
What is exudate rich in?
Proteins, it has a high specific gravity
What is purulent exudate otherwise known as?
Pus, it is rich in leukocytes and debris of dead cells
What does ultraflitration of plasma create?
a transudate with low protein content and little to no cellular material/ low specific gravity
Why does vasocnstriction occur immediately after insult to the tissue occurs?
To limit the blood loss
What two things does vasodilation do during inflammation?
Allows increased blood flow to the tissue
Causes Erythema (heat and redness) at the site
What two substances induce vasodilation in the smooth muscle of the vessels
Histamine and nitric oxide
What three mechanisms promote the increase in vascular permeability
Contraction of endothelial cells (increasing interendothelial spaces)
Endothelial injury (necrosis and detachment)
Increased transport through the endothelial cells (transcytosis)
What is the most common mechanism of increasing vascular permeability?
Contraction of endothelial cells
When does the contraction of endothelial cells occur?
It occurs immeditaely after exposure to the mediator and is short lived (around 15-30 minutes)
What are some examples of chemical mediators?
histamine. bradykinin, leukotrienes, neuropeptide P
What are some examples of situations that would delay contraction of endothelial cells
forms of mild injury, e.g burns/ ultraviolet radition and exposure to bacterial toxins
vascular leakage can then begin after a delay of 2 to 12 hours and last for several hours or even days
What is endothelial damage?
Direct damage leads to necrosis and detachment from the basement membrane
this occurs in severe injuries such as burns or by the action of microbes that target endothelial cells (endotheliotropic)
What is transyctosis?
Where fluids and proteins are transported through endothelial cells
What is a vesiculovacuolar organelle?
a channel created by vesicles and vacuoles
What effect do mediators have on transyctosis?
They promote transport by increasing the number and size of the channels
What is the effect of plasma leaving the vessel?
acts to dilute the stimulus of acute inflammation
What occurs to fibrinogen during increased vascular permeability?
Its one of the proteins that leaves vessels in exudates
What does fibrinogen polymerise to become?
It polymerises to become fibrin
What are the functions of fibrin?
It stops the stimulus spreading to another tissue
Allows the leukocytes to target the inciting cause of inflammation
Assists in blood clotting
Acts as a scaffold for endothelial migration during wound healing
What is stasis?
vascular congestion (slower blood loss and increased viscosity)
What is the purpose of stasis?
allows leukocytes to accumulate on the vascular endothelium
endothelial cells are activated by mediators of inflammation so they express increased levels of adhesion molecules
Leukocytes can then adhere to the endothelium and migrate through the vessel wall
What is the role of lymphocytes?
Lymphatics normally drain the extravascular fluid (lymph) and take it to the lymph nodes
What is lymphangitis?
Secondary inflammation of the lymphatic vessels can occur
What is it called when a drained lymph node becomes inflamed?
lymphadenitis
What is it called when lymph nodes increase in size due to hyperplasia of lymphoid follicles/
reactive/inflammatory lymphadenitis
How are leukocytes recruited?
- Adhesion to the endothelium
- Migration across the vessel wall
- Migration to the stimulus
How does adhesion between the leukocyte and endothelial cell occur?
Via complimentary adhesion molecules