Lecture 14: Transudates and Exudates Flashcards
True or False: Inflammation is a sign of autolysis?
- True
- False
True or False: Inflammation is a sign of autolysis?
- True
- False
When there’s autolysis, the body is dead and inflammation can’t happen. Inflammation is an active process, and won’t happen in an animal that’s deceased.
Which of these in an appropriate morphologic diagnosis?
- Caseous necrosis
- Lymph node, necrosis, chronic
- Caseous lymphadenitis, diffuse, chronic
- Lymphadenitis, diffuse
Which of these in an appropriate morphologic diagnosis?
- Caseous necrosis
- Lymph node, necrosis, chronic
- Caseous lymphadenitis, diffuse, chronic
- Lymphadenitis, diffuse
It has a location, duration, organ and process
Pancreatitis is to pancreas as typhlitis is to:
- Cecum
- Ear
- Toe nail
- Trachea
Pancreatitis is to pancreas as typhlitis is to:
- Cecum
- Ear
- Toe nail
- Trachea
In normal microvascular flow, __________ __________ is high on the arteriole side of the capillary, and __________ __________ is high on the venule side of the capillary.
In normal microvascular flow, hydrostatic pressure is high on the arteriole side of the capillary, and oncotic pressure is high on the venule side of the capillary.
During acute inflammation, what forces or factors promote the accumulation of fluid exudate in the interstitium?
- Increased hydrostatic pressure in the arteriole capillary beds
- Increased vascular pressure
- Increased oncotic pressure outside the vascular space
How does increased arteriole hydrostatic pressure lead to the formation of thrombus, at a site?
If you have increased arteriole hydrostatic pressure, that will cause protein loss through the interendothelial junctions. That increases the oncotic pressure outside of the vascular space, which the body tries to correct by fluid loss from the vasculature. Decreased fluid on the arteriole side of the capillary means that you could have stasis, because there’s decreased fluid. That can meet the criteria for the formation of a thrombus at that site.
What is the first reflex to hemostasis?
Vasoconstriction
How does vasodilation play a role in acute inflammation?
Vasodilation increases the flow in arterioles. The meta-arteriolar sphincter opens, the hydrostatic pressure increases, and the venules dilate.
What compound is a major player in the expansion of interendothelial junctions?
Histamine
Where two endothelial cells would usually meet and form a barrier, under the influence of histamine they will retract, and open up that space.
What are some mechanisms of increased vascular permeability?
- Retraction of endothelial cells
- Endothelial injury
- Leukocyte-mediated vascular injury
- Increased trancytosis (when cells cross an intact endothelial cell)
Side note: We won’t talk about increased transcytosis much. Just be aware that it happens.
Tell me more about the retraction of endothelial cells, as a mechanism of increased vascular permeability.
- Occurs mainly in venules
- Induced by histamine, NO, other mediators
- Rapid and short-lived (minutes)
Tell me more about endothelial injury, as a mechanism of increased vascular permeability.
- Occurs in arterioles, capillaries, venules
- Caused by burns, some microbial toxins, nearby thrombus, crushed in a traumatic event
- Rapid: may be long-lived (hours to days)
Perhaps they’ve been overstimulated, they’ve been over activated by the presence of LPS
These cells simply cannot cover that vascular space anymore
Tell me more about leukocyte-mediated vascular injury, as a mechanism of increased vascular permeability.
- Occurs in venules, pulmonary capillaries
- Associated with late stages of inflammation
- Long-lived (hours)
What are the characteristics of a transudate?
Low Specific Gravity (1.012 or less)
Low protein concentration
Low cellularity
Typically a clear fluid
What are the characteristics of an exudate?
Increased Specific gravity (~1.020)
Increased protein concentration (>4g/dl)
Increased cellularity (accumulates over time)
Typically a cloudy, opaque fluid
What is a modified transudate?
Somewhere in between a transudate and an exudate.
May have high protein concentration, but low cellularity, or vice versa
We’ll cover this more in clin path, just know it exists for now.
In the fluidic phase of inflammation (increased vascular permeability), what happens:
- Increased viscosity of blood
- Margination of leukocytes and platelets
- Proteins (fibrinogen and globulins) move into the interstitium
- Possible thrombosis of small vessels and lymphatics
- Increased lymphatic flow early, may or may not lead to later thrombosis
What are the steps of the leukocyte adhesion cascade?
- Rolling
- Adhesion
- Transendothelial migration
What are the steps of cellular exudation?
- Margination (rolling: selectins)
- Stable adherence (upregulation of selectins)
- Emigration/Transmigration (actual movement of cells out of the vasculature)
- Chemotaxis (directed locomotion via chemical stimulus)
What are the proteins that play a role in stable adherence and emigration/transmigration?
Stable adherence: Chemokine upregulation of ICAM-1
Emigration/Transmigration: PECAM
More info on them (from wikipedia):
ICAM-1 - This protein is a type of intercellular adhesion molecule continuously present in low concentrations in the membranes of leukocytes and endothelial cells. Upon cytokine stimulation, the concentrations greatly increase. ICAM-1 can be induced by interleukin-1 (IL-1) and tumor necrosis factor (TNF) and is expressed by the vascular endothelium, macrophages, and lymphocytes.
PECAM-1 is found on the surface of platelets, monocytes, neutrophils, and some types of T-cells, and makes up a large portion of endothelial cell intercellular junctions. The encoded protein is a member of the immunoglobulin superfamily and is likely involved in leukocyte transmigration, angiogenesis, and integrin activation.
Walk me through what happens when you have an acute inflammatory stimulus, like a cut or a foreign body under the skin,
Acute inflammatory stimulus: Sliver, maybe a cut, maybe a foreign body gets driven under the skin
Now you have antigens, maybe bacteria, maybe plant fibers. This will serve as a stimulus for neutrophil recruitment. This takes place through a variety of Inflammatory mediators: cytokines, chemokines. L-selectin is then expressed on neutrophils. When the endothelial cells are in the presences of certain cyto/chemokines, the receptor will be more strongly expressed on the endothelial cells.
This tethers the neutrophil to the endothelial cell, which allows for the expression of additional mediators. This results in the pulling of these cells through the vascular wall, towards the initial stimulation.
What are some chemotaxins for PMNs?
PMNs = polymorphonuclear leukocytes = neutrophils, mainly
C5a, Bacterial products, FDPs, Chemokines (like IL-1), LTB4 (Leukotriene B4), PAF (platelet activating factor), Dead cells (necrotaxis)
What are some chemotaxins for macrophages?
C’, Bacteria, Cationic proteins from PMNs, Chemokines (IL-8)