Inflammation Flashcards
innate immune system
the unchanging immune system we’re born with. It has the same response every time it’s activated (non-specific)
adaptive immune system
the immune system we continually develop as we are exposed to different pathogens over our lifetime. It has memory and is unique to each person
3 lines of defense against pathogens
- Innate immune system - natural barriers
- Inflammation
- Immune system - adaptive immunity
natural barriers
our first line of defense that includes skin and mucous membranes. They can be mechanical or chemical barriers
mechanical barriers
cilia, sloughing, mucous, etc.
chemical barriers
acidic pH of stomach or vagina, saliva
humoral immunity
an immune response derived from body fluids such as the plasma. Inflammation uses the complement system and the immune system uses antibodies through B cells to tag the pathogen
cellular immunity
an immune response that occurs between cells. Inflammation recruits neutrophils and macrophages and lymphocytes (T and B cells) are recruited in the immune response involving an intracellular or processed antigen. Does not involve antibodies
inflammation
the protective response of vascularized tissue that involves eliminating the initial cause of injury, removing damaged tissue, and building new tissue
goals of inflammation
- movement of blood and cellular components to site of injury
- delivery of nutrients and blood cells to get rid of the offender
- injurious agents are diluted, confined, and eliminated
- stimulate and assist the immune system
- promote healing and generate new tissue
how goals of inflammation are accomplished
- Increased metabolic rate to increase production of cellular items needed for battle
- Vasodilation to speed up delivery of cellular components to site of injury
- Increased vascular permeability to allow leukocytes (namely neutrophils), proteins, and nutrients into affected tissue
causes of inflammation
- Microbes
- Immune reactions between antigen and antibody
- Trauma
- Burns
- Physical/chemical agents
- Tissue necrosis
- Temperature extremes
- Oxygen deprivation
- Nutrient deprivation
- Genetic/immune defects
- Ionizing radiation
Characteristics of acute inflammation:
- Response to injury/insult that occurs early and quick (mins to hours)
- Triggered by variety of stimuli
- Doesn’t last very long, self limiting
- Non-specific (ex. response for cutting finger/stubbing toe is exactly the same)
- 2 phases (vascular and cellular)
- Results in either healing or chronic inflammation
What cells are involved in inflammation? 7
- Endothelial cells
- Platelets
- Neutrophils
- Monocytes/macrophages
- Eosinophils
- Basophils
- Mast cells
Function of endothelial cells?
- Line blood vessel walls, tight space under normal conditions, limits movement
- Produce antiplatelet/antithrombotic agents to prevent clots
- Regulate leukocyte extravasation through use of adhesion molecules
- Regulate immune cell proliferation
- Participate in repair process
What are platelets also known as?
Thrombocytes
Function of platelets?
- Primary role = hemostasis
- Activated then produce inflammatory mediators leads to increased vascular permeability, chemotaxis, adhesive and proteolytic properties of the endothelium
Function of neutrophils?
- Chief phagocytic leukocytes
- Have lysosomal enzymes, called upon to destory invaders and remove debris
What are bands?
Immature neutrophils
What does it mean when the band count is elevated on a CBC?
Bone marrow is overworked
Function of monocytes/macrophages?
- Leukocytes derived from bone marrow
- Larger and fewer lysosomes than neutrophils
- Stimulate growth of granulocytes and monocytes in the bone marrow and substances that promote wound healing
- Replace neutrophils as they die off
When do macrophages appear?
Later than neutrophils (24-48 hours post injury)
What are macrophages associated with?
chronic inflammation
What do macrophages produce?
Potent vasoactive mediators
- Prostaglandins
- Leukotrienes
- Platelet activating fcator
- Inflammatory cytokines
- Growth factor
How long are macrophages lifespan?
3-4x longer than neutrophils
What happens to neutrophils when they die?
- Become exudate (pus)
- Release chemotactic factor to attract macrophages to injury
When do neutrophils appear?
- Early in inflammatory process (90 mins to 6-12 hrs post injury) cells attracted to site because of chemotactic factors
What causes an increased demand for neutrophils?
- Severe inflammation, bone marrow cannot keep up and releases bands
Function of eosinophils?
- Prominent in allergic response and hypersensitivity disorders
- Good at tackling parasitic infections
- Circulate in blood until needed,
- migrate to tissue where they modulate release of inflammatory mediators
- degrade vasoactive molecules,
- controlling vascular effects of histamine and serotonin
What are eosinophils?
Granulocytes with many lysosomes
What do eosinophils do?
- Circulate in blood until needed,
- migrate to tissue where they modulate release of inflammatory mediators
- degrade vasoactive molecules,
- controlling vascular effects of histamine and serotonin
Function of basophils?
- Produce lipid mediators and cytokines to induce inflammatory response
- Important in allergic and hypersensitivity reactions
- Trigger histamine and vasoactive agent release
Function of mast cells?
- Mast cell degranulation
- Activate the 3 plasma protein systems
- Release of cell derived mediators
- Important in response to hypersensitivity and allergic reactions
Where are mast cells located?
Connective tissue, close to blood vessel, prevalent along mucosa of lung, GI tract and dermis of skin
What do mast cells produce?
Lipid mediators and cytokines which induce inflammation
What is within neutrophils cytoplasm??
Pre-formed granules
What are the contents of these granules?
- Histamine
- Serotonin
- Chemotactic factors
- Enzymes
- Proteoglycans
- Proteases
- Cytokines
What are the three plasma protein systems
- Complement system
- Clotting system/coagulation cascade
- Kinin system
What do complement fragments cause?
Vasodilation, increase vascular permeability and enhance activity of phagocytes
What do C3 and C5 do?
Formation of opsonins, chemotactic factors and anaphylatoxins
C3b?
used in the opsonization and tagging
C5a?
Chemotactic and anaphylatoxic factors
C2b?
Increase vasodilation/permeability (smooth muscle relaxation)
C4a?
Anaphylatoxin inducing cell degranulation with histamine release
What is the endpoint of the complement cascade?
Formation of membrane attack complex (MAC) composed of C5-C9, creates holes in membranes of pathogens, allows water in and causes cells to explode
What are the three ways to activate the complement cascade?
- Classical pathway - activated by antibodies, immune system can take advantage of this for the destruction of bacteria
- Lectin pathway - activated by bacterial carbohydrates, no antibody required
- Alternative pathway - activated by gram negative bacteria, fungal cell wall polysacchardies (endotoxins) no antibody required