Acute Inflammation Flashcards
What are the 5 cardinal signs of inflammation?
- Reddening from increased blood flow
- Swelling as exudation of fluid from dilated blood vessels into inflamed tissue occurs
- Heat as increased blood flow
- Pain as chemical mediators are released into damged tissue and by local pressure on nerve endings from the exudate
- Loss of function reluctance to sue inflamed portion
What are the causes of inflammation?
- Microorganims and parasites
- Trauma: mechanical, chemical and thermal insults
- Abberant immune responses - hypersensitivity and autoimmunity
- Malignant neoplasms
How do we classify types of inflammation?
Acute or Chronic
What does acute mean in terms of inflammation?
Sudden onset of inflammtion tha lasts for a few hours or days
What does acute inflammation lead to?
- Death
- Resolve by regeneration and immunity
- Fibrotic repair
- Become chronic
Grossly how can we tell acute and chronic inflammation apart?
Acute - Swollen and dark red in colour
Chronic - Shrunken and light brown/tan
What is Phase 1 of acute inflammation?
The Vascular Phase:
1. Within seconds arteriole constricition occurs as smooth muscle responds
2. Hyperaemia (within minutes - days) arteriole and capillary dilation caused by chemical mediators
What is Phase 2 of acute inflammation?
Fluid leaves the circulation and begins to accumulate in the tissues this occurs as mast cells release specific mediators into serum
Vascular permeability is increased due to endothelial cell contraction(caused by histamine release) - cell junctions of endothelial cells open and allows protein-rich fluid (exudate) to escape into the surrounding tissue
What are the components that make up exudate?
- Water and electrolytes
- Plasma proteins (albumin, globulin, fribrinogen)
- Red blood cells
- Platlets
What is Phase 3 of acute inflammation?
Migration of leukocytes:
a) Margination/Pavementing - Altered blood flow and loss of axial stream (white blood cells move to periphery of vessels and begin to adhere), expression of adhesion molecules
b) Chemotaxis - Neutrophilsd move along a chemotactic gradient macrophages are slightly sloer - chemotaxis attracts leukocytes and activates them
c) Emigration via intracellular junction - motile cells force an opening and the basement membrane is breached
What are neutrophils?
White blood cells formed in the bone marrow that contain multilobed nuclei and are indistinctly granulated:
They have a short half-life in the blood (6 hours) and are replaced twice a day
When they enter tissue they do not return to the blood
What are the functions of neutrophils?
- Phagocytosis of microorganisms or foreign material and fusion of phagosome with lysosomes to kill or degrade material
- Secretion and/or release of granuels into exudate to enhance acute inflammatory response
How are neutrophils recruited to the site of inflammation?
- Marginate in small veins (venules) and capillaries
- Loosely stick to wall of venule/capillary and roll along
- At junction between endothelial cells, neutrophils migrate out
- Migration continues to the site of damage
What are eosinophils?
White blood cells formed in the bone marrow contain multilobed nuclei and distinct granuels in the cytoplasm:
Similar half life to neutrophils they are prominent within parasitic infection and local allergic reactions
What are mast cells?
Heavily granulated mononuclear cells found in tissues they have a long life span (4-12 weeks) depending on their location and degranulate in tissue injury releasing histamine, heparin, and 5-hydroxytryptmine (serotonin) - chemical mediators responsible for vasodilation, chemotaxis and pain
