Pathology Flashcards
What is the definition of inflammation?
a well organized cascade of fluid and cellular changes within vascularized tissue; host response to remove damaged/necrotic tissue or foreign invaders
What are the 5 cardinal signs of inflammation?
Heat
Redness
Swelling
Pain
Loss of function
How is inflammation part of the process of repair and healing?
destroys, dilutes or wall off injurious agents
initiates healing and tissue repair
How is inflammation a protective response?
It gets rid of pathogens
Removed nectrotic debris (phagocytosis
Repair the damage= return to normal structure/function
What are the types of inflammation?
Acute and Chronic
What are the characteristics of acute inflammation?
short duration (minutes to days)
exudation of fluid & plasma protein (edema)
emigration of leukocytes (mostly neutrophils)
What are the characteristics of chronic inflammation?
Longer duration (days to years)
Macrophages & lymphocytes
Proliferation of blood vessels & connective tissue
What are the 3 main components of acute inflammation?
1) vascular alteration leading to increased blood flow (hyperemia)
2) Changes in microvasculature permeability that allow plasma proteins & leukocytes to leave the circulation
3) Emigration of leukocytes into the perivascular area
What are the stimuli for acute inflammation?
Infections
Trauma
Physical & chemical agents
Tissue necrosis
Foreign body
Immune reactions
What is exudate and when does it form?
inflammatory extravascular fluid with:
high protein concentration (> 5 g/dL)
high cell content (> 5000 leukocytes/mL)
specific gravity >1.020
Formed when there is significant alteration in small blood vessel permeability at the site of injury (increased interendothelial spaces)
What is transudate and when does it form?
extravascular fluid with:
low protein concentration (< 2 g/dL)
low cell content (< 1500 leukocytes/mL)
specific gravity <1.012
Formed due to an ultrafiltrate of blood from either increased hydrostatic pressure or decreased oncotic pressure
What is edema?
accumulation of fluid in interstitial or serous cavities
What are the 4 main mechanisms that result in edema?
1) increased vascular permeability
2) increased intravascular hydrostatic pressure
3) decreased intravascular osmotic pressure
4) decreased lymphatic drainage
What is pus?
a purulent exudate rich in leukocytes (mostly neutrophils) and cell debris
What are some vascular changes in acute inflammation?
Vasodilation involves arterioles first, then results in opening new capillary beds
Increased permeability of microvasculature
loss of fluid results in concentration of RBCs in small vessles, increased blood viscosity & blood stasis
What are the 4 mechanisms for vascular leakage?
1) endothelial contraction
2) direct endothelial injury
3) leukocyte-dependent injury
4) increased transcytosis
What are the endothelial changes involved in contraction?
It increases in interendothelial space
It is mediated by histamine, bradykinns, leukotrienes
Rapid and short-lived
Occurs mainly in venules
Induced by histamine and NO
What are the endothelial changes associated with direct injury?
Direct damage to endothelium causes necrosis & detachment
Starts immediately, lasts until thrombosis occurs or endothelium repaired
Rapid and may be long lived
Occurs in arterioles, capillaries, venules
Caused by burns, & some microbial toxins
What are the endothelial changes associated with leukocyte-mediated injury?
Activated leukocytes may secrete free radicals & proteolytic enzymes, leading to cell damage
Occurs in venules, pulmonary capillaries
Associated with late stages of inflammation
Long lived (hours)
What are the endothelial changes associated with transcytosis?
Increased transport of fluid & protein through endothelial cells occurs in venules
What are the vasoactive amines?
Histamine
Seratonin
What are the arachidonic acid metabolites?
Nitric oxide (NO)
Cytokines
What are the plasma derived mediators?
Complement system
How is histamine presented?
Is a performed state in mast cells, basophils & platelets in cytoplasmic granules
