Lecture 2 E1-Acute Inflammation/ Cardinal Manifestations Flashcards
What are the 7 etiologies that can cause inflammation?
Microorganisms, Hypoxia/Ischemia, Nutritional Deficiencies, Trauma/Surgery, Radiation, Caustic Chemicals, and Extreme Heat/Cold
what is the first line of defense
skin and mucus membrane
- tears, saliva, gut flora, gastric acid
- help rid our body of bacteria before it gets into the system
what is the second line of defense
inflammatory response
- non specific and rapid
- acute inflammation expected (this is normal but patients may think it is an infection if they see a bit of red swelling)
- can happen without a pathogen
what is the third line of defense
the immune response
what is etiology of acute inflammation and what are some types of etiologies
any damage or alteration to normal tissue ( cause of disease)
-microorganisms
- hypoxia/ischemia
-nutritional deficiencies(iron, B12)
- trauma/surgery
-radiation (sunburn, treatment)
- caustic chemicals
- extreme heat/cold (burns, frostbite)
2 Main Components of the Vascular Response in acute inflammation
Increased Blood Flow to injury site
Increased blood vessel permeability at in the injury site
what is the point of the cellular response of acute inflammation
removal of offending agent and damaged tissue
3 Major Components of Acute Inflammation
Vascular Response,
Cellular Response, and
Inflammatory Mediators
What are the 2 major anatomical changes that occur during the vascular response?
Increased blood vessel dilation
Increased blood vessel permeability
what does increased vessel permeability allow?
allowing WBC, other cells, and nutrients to get into our tissues easily
What are the steps of the vascular response?
- Transient vasoconstriction for possibility of blood loss ( initial step- doesn’t last long)
- Local blood vessels dilate (vasodilation) to increase blood flow to area and enhance the transport of blood and cells. (within seconds-minutes)
- Endothelial cells lining the vessels contract to open up gaps in the intracellular junctions, which is increased permeability. (allowing WBC and plasma to enter injured site)
- Increased vessel permeability allows for plasma and cells to travel to the injured tissue.
This results in dilution of the pathogen via exudation of fluid, stagnated blood flow in the vessel at that location, slowing the spread of the offending agent, and clotting elements can move into the injury site.
What are the 3 types of capillaries?
Continuous, Fenestrated, and Sinusoids (discontinuous)
Where do I find fenestrated capillaries?
Endocrine organs, small intestine, and the choroid plexus.
what is the most common type of cappilary
continuous capillaries
Where do I find continuous capillaries?
CNS (blood-brain barriers) and lungs.
Where do I find sinusoidal capillaries?
Bone marrow, spleen, and liver.
What are the 3 major patterns of vascular response?
Immediate Transient: post minor injury
- hitting in face makes you turn red due to vasodilation then goes away
Immediate Sustained: post major injury (most common)
- response lingers
Delayed Hemodynamic: 4-24 hrs post injury.
-exposure to chemicals, sunburn
What is the cellular response?
Movement of phagocytic WBCs into area of injury.
- granulocytes (neutrophils)
- monocytes
what are the 4 steps of the cellular response
- Margination/Adhesion
- Migration/Diapedesis
- Chemotaxis
- Phagocytosis
What are the steps of margination/adhesion (step 1)?
- An injury causes cytokine (chemical mediators) release (influence cells on vessels to release selectins) .
- Cytokines (IL-1 and TNF-alpha) cause an increased expression of adhesion molecules, specifically selectin.
- Leukocytes have slowed migration and begin marginating/pavementing along the periphery of vessels.
- Adhesion to the vessel walls(allows advancement to step 2).
what is selectin and what does it do
surface protein and adhesion molecule,
allows WBC to stick to vessel walls to stop them from moving
- think of velcro strips on the floor and rolling tennis ball on them
What is migration/diapedesis?
It is when WBCs extend their pseudopods and pass through the capillary wall via ameboid movement.
What is chemotaxis and the components of it?
Chemotaxis is when leukocytes travel throughout the tissue to the site of injury.
It is signaled by cytokines and complements (C3a and C5a)
- cytokines move to move the concentrated area of the leukocytes to where injury is “leaves a trail to the injury”
What is phagocytosis and opsonization?
Phagocytosis is the engulfment of cells.
what is opsonization
the recognition and attachment of a cell, done usually by C3b.
- tagging ( coat with antibodies) harmful cells so WBC can recognize it is harmful and engulf then kill it
What is a Neutrophil?
AKA a polymorphonuclear neutrophil (PMNs) or segmented neutrophil (segs)
It is the primary phagocyte to arrive early to the injury site (first responder) and arrives in ~90 minutes with a duration of 10 hrs.
- patrol the body when there is no injury present then bump up speed when there is one
how are neutrophils maintained
need to be constantly replaced to maintain their numbers
- causes increase in circulating WBC -leukocytosis
- due to the increased demand, immature forms may be released and these forms are called “bands/left shift/bandinia”
immature forms released if there is intense infection requiring more neutrophils
What is leukocytosis?
The increased production/presence of WBCs in serum. Usually neutrophils.
can be caused by inflammation or infection (or medications, bone marrow disease)- intereferes with margination (steroids inhibit)
Eosinophils
For allergic and primarily parasitic infections.
Basophils
For inflammation and allergic reactions
Can release histamine
Bonds with IgE
Mast Cells
Similar to basophils but reside in portals of entry and act as sentinel position cells. Also commonly seen in allergic and parasitic infections with IgE.
-first responders that degranulate cells
Monocyte (8)
- Largest WBC
- Arrives ~24 hrs post injury,
- way longer life span than PMNs
-majority cell type after 48 hrs(now is the main cell in injury site). - NOT a granulocyte
- engulf larger and greater quantities of foreign material than neutrophils
- more efficient, and give an ADAPTIVE immune response when recognized specific pathogens
- called a macrophage when it is inside tissue
Platelets/Thrombocytes
Helps mediate vascular response
Involved in hemostasis and thrombosis
Releases inflammatory mediators
erythrocytes
red blood cells, transport oxygen to tissues
Endothelial cells
-Involved in vascular response
-Synthesizes and releases inflammatory mediators
- help get WBC to target with selectins
What are the general effects of an inflammatory mediator?(6)
Affects vasodilation, chemotaxis, platelet aggregation, endothelial cell stickiness, pain, and vascular permeability.
What are the inflammatory mediators?
Plasma proteins (3), Histamine, Cytokines, Platelet Activating Factor, Prostaglandins, and Leukotrienes
What are the 3 Plasma Proteins?
Kinins, Complements, and the clotting system
What are Kinins?
A plasma protein that causes
-vasodilation,
- increased vascular permeability,
- smooth muscle contraction ( nonvascular- kicks out or restricts pathogens)
-involved in the pain response.
Most common is bradykinin (most important in inflammatory response).
They are broken down by Kininases and ACEs.(angiotensin converting enzyme)
float around in blood stream
What is the clotting system?
Plasma proteins involved in clotting. Generally, fibrinopeptides are formed along with a thrombus.
Thrombin is the key protease enzyme.
Functions include expression of endothelial adhesion molecules (selectin) and production of prostaglandins, PAF, and chemokines (inflammatory mediators).
since inflammation is not specific, clots can form in CASE needed
What is the complement system?
-present in inactivated forms in plasma
(activated to become proteolytic enzymes)
(degrade other complement proteins in a cascade)
major function of the complement system (5)
- vasodilation and increased vascular permeability
- smooth muscle contraction
- leukocyte activation, adhesion, chemotaxis
- augmentation of phagocytosis
- mast cell degranulation (release what is in granules
what effector molecules are present during complement system
C3a and C5a (help with immune repsosne)
Histamine
An inflammatory mediator released by mast cells, basophils, and platelets.
Plays a major role in vascular response via H1 receptor, causing vasodilation and increased vascular permeability.
It is one of the first mediators of inflammation.
stuffy nose- blood vessels open