Chapter 3, inflammation and Repair Flashcards
Define inflammation?
a response of vascularized tissues to infections and tissue damage that brings cells and molecules of host defense from the circulation to the sites where they are needed, to eliminate the offending agents.
damaged cells secrete mediators such as (cytokines).
acute and chronic inflammation, differences.
- acute inflammation: develops within hours and is of short duration. Edema results
- Chronic inflammation: longer duration and is associated with more tissue destruction, lymphocytes and macrophages, the proliferation of blood vessels and fibrosis.
what are the external manifestations of inflammation (cardinal signs)?
-Heat (calor in latin)
-redness (rubor)
-swelling (tumor)
-pain (dolor)
-loss of function (functio laesa)
both excessive and defective inflammation can be harmful.
define scarring?
the residual defects with connective tissue due to missing cells that had been eliminated due to an inflammation
when is inflammation terminated?
it is terminated when the offending agent is eliminated. the cytokines are degraded and anti-inflammatory substances are released.
stimuli that will trigger inflammation?
-Infections (bacterial, viral, fungal, parasitic)
the morphologic pattern of the response can be useful in identifying its etiology.
-tissue necrosis
-foreign bodies (dirt, splinters, sutures)
-immune reactions
what type of receptor is used to detect infectious pathogens?
toll like receptors (TLR)
what do Toll like receptors recognize?
pathogen-associated molecular patterns (PAMP). once recognized the cell secrete:
cytokines that induce inflammation, anti-viral cytokines and cytokines and membrane proteins that promote lymphocyte activation.
what are the sensors of cell damage?
cytosolic receptors that recognize molecules that are liberated or altered as a consequence of cell damage.
they are called DAMPS, (Damage associate molecular patterns)
-uric acid (product of DNA breakdown)
-ATP (released from damaged mitochondria)
-reduced cytosolic (K+) due to membrane damage.
-DNA (when is leaves the nucleus into the cytosol)
the 5 steps of inflammation?
“the 5 R’s”
- recognition of the injurious agent
- recruitment of leukocytes
- removal of the agent
- regulation (control) of the response
- resolution (repair).
Acute inflammation 3 components?
1-dilation of small vessels increasing blood flow
2-increased permeability of vessels, enabling proteins and leukocytes to leave circulation
3-emigration of the leukocytes from the microcirculation their accumulation as the site of injury.
phagocytes and other sentinel cells in thee tissues recognize the presence of the foreign or abnormal substance and release mediators to initiate the above processes.
what is exudation?
the increased permeability of the vessels in response to inflammation resulting in fluid and proteins and blood cells from the vessel.
what is exudate?
an extravascular fluid that has a high protein concentration and contains cellular debris indicating an inflammatory reaction.
what is Transudate?
a fluid with low protein content, little or no cellular material, and low specific gravity. Ultrafilatrate of blood do to osmotic imbalance.
Define edema?
an excess of fluid in the intersitial tissue or serous cavities; it can be either an exudate or a transudate
Define Pus (purulent exudate)
an inflammatory exudate rich in leukocytes (mostly neurtophils) the debris of dead cells, and in many cases microbes.
what causes the redness and heat at the site of inflammation?
Histamine causing vasodilation.
what is the result of the loss of fluid during inflammation.
slower blood flood, high RBC concentration in small vessels, increased viscosity.
RESULT: engorgement of small vessels jammed with slowly moving RBC (vascular congestion)
ERYTHEMA: localized redness of the involved tissue.
what increases vascular permeability?
- Retraction of endothelial cells (histamine, bradykinin, leukotrienes
- Endothelial injury (leakage can last hours until vessel is repaired).
- increased transcytosis in endothelial cells.
What is lymphangitis
-secondary inflammation of the lymphatics
What is lymphadenitis?
inflammation of the lymph nodes that enlarge.
red streaks near a skin wound is a telltale sign of an infection as the streaking follows the course of the lymphatic channels (indicating lymphangitis)
most important leukocytes for inflammation?
the ones capable of phagocytosis; neutrophils and macrophages.
Neutrophils respond faster.
Macrophages respond slower but longer action. Macrophages aid repair by secreting growth factors.
How does strong activation of leukocytes can cause “collateral damage”
leukocytes emit substances that help destroy the microbes and clean up necrotic tissues can affect healthy ones as well.
what are the 3 things that happen when leukocytes encounter and infection?
- adhesion to endothelium
- leukocyte migration through endothelium
- chemotaxis of leukocytes