Patho- Understanding the Immune System Flashcards
Protection of the body depends on three major lines of defense:
Skin and mucous membranes
The inflammatory response
Immune response
-Our bodies are made to be strong, survive, and be healthy
Body has natural defense systems to fight back
Three most important
First line of defense
Skin Mucous membranes Blink reflex Lashes Tears
-Skin- intact, protects against environment-skin has bacteria on it but it is intact so it doesn’t harm us
Mucous membranes- chemical substances present that fight off bacteria
-blink reflex- -lashes-protect-keep things out -nasal hair- -acid in stomach-protects us and kills off what isn't supposed to be there -cilia-cough reflex -tears-chemical that kills whatever gets in eye, eye washes away what's in there- chemical neutralizes Healthier person is better defense mechanisms work
Second line of defense
Inflammatory mechanisms are activated
Vasodilation and increased capillary permeability cause erythema (redness) and edema (swelling)
Phagocytes move in to engulf and destroy harmful substances.
Inflammatory-comes into play if first line of defense doesn’t work
Isolates and rids bacteria or problem
How effective, depends on how healthy you are
Blood vessels dilate, to get blood to effected area, erythema (redness), edema-swelling-happens because of the permeability of weakened vessel, phagocytes move in (pac-man) clear all of the bacteria (if not heathy then a doctor has to act as a phagocyte and clear the dead tissue)
Third line of defense
Immune Response is activated
Immune cells recognize and destroy harmful substances. adequate response-resolution inadequate response-disease spreads.
Immune response comes into play when 2nd line of defense doesn’t work.
Last effort- cells recognize bad guys and destroy it—if it works person will get better—if it doesn’t work disease spreads or person dies
inflammatory response
Activated when the first line of defense is inadequate
Nonspecific
Process of the response is identical regardless of the cause of injury
Universal-nonspecific-same in everyone regardless injury-how persons body responds, whether it is effective or not
Acute inflammation
Triggered by tissue injury and is essential to healing
Injury is defined as any form of damage or alteration to cells or tissues
Injury can include:
Invasion by microorganisms
Cellular mutations
Hypoxia or anoxia
Nutritional deficiencies
Physical or chemical damage.
ACUTE-rapid onset-time limited-max 2 weeks
Symptoms are worse
Cells become mutated
Hypoxia-lack of oxygen to tissues and cells
Anoxia-absent of oxygen
Eschemia- reversable oxygen
Necroses-complete cell death
Nutrition deficiencies can cause inflamation
Acute inflammation process
The ability to recognize injury
Activate a response
Appropriately shut down the response when the injury has passed
Result is either tissue repair or regeneration or formation of scar tissue.
System has to recognize injury
- activates a response
- if cells in body made to recognize injury don’t work then the first thing doesn’t happen and it makes it harder
- cells-lets go fight
- time limited-once problem is resolved inflammation stops-complete tissue repair-or regeneration occurs-scar tissue develops
Goals of acute inflammation
3 major goals:
To increase blood flow to the site of injury, referred to as the vascular response
To alert the products of healing to attend to the site of injury, which is referred to as the cellular response
To remove the injured tissue and prepare the site for healing
vascular response
Tissue injury requires a response at the level of the blood vessel near the site of the injury
Clotting and healing must occur to prevent infection
Structure of the blood vessels must change:
Dilate (widen) to accommodate increased blood flow to the site of injury
Lining of the blood vessel becomes more permeable (loosens to allow cells to easily move from the vessel into the injured tissue).
VASCULAR RESPONSSE
Blood vessels dilate-to get blood to area-to give it oxygen
Blood has got to go to injury site
Alert all cells involved in healing
Cells-closes to site are first to respond
Clotting
Cellular response
PHAGOCYTOSIS HAS TO OCCUR
Get rid of old (dead) get ready for new
Vascular response-blood and fluid needed
- Blood is composed of cells active in phagocytosis
- Increased fluid dilutes harmful substances at the site of the injury
Exudate (watery fluid) that accumulates at the site of injury: high in protein and leukocyte concentration: sign that the vessels are more permeable and cells active in phagocytosis are present
Inflammatory mediators: facilitate the process of widening and loosening of the blood vessels at the site of injury; located in the blood plasma, platelets, mast cells, basophils, neutrophils, endothelial cells, monocytes and macrophages
Blood is composed of oxygen-but blood also brings cells involved of phagocytosis
Fluid comes to site from blood vessels dilating and becoming PERMIBLE
If you pop a blister-it will get rid of protein the body needs-so it bad
inflammatory mediators within cells
Most mediators are formed within the cell
Within cells, most of these are generated in the cell plasma membrane or are made up of proteins within the cell
Most commonly, it is the white blood cells that produce and release the mediators
Platelets, endothelial cells and injured tissue cells are also potential sources.
Mediator-helps you fix a situation-sent in to help a process
Most are in plasma membrane(made of protein within the cells)
Have to have a good source of protein-for good healing
Most important ones come from white blood cell
Blood cells
Mast cell: important inflammatory mediator
Are leukocytes in the connective tissues; near blood vessels
Location allows for rapid response directly at the site of injury
Responsible for the production and immediate release of inflammatory mediators
Basophil: white blood cell; contains granules; functions similar to the mast cell
Signals to trigger, enhance and discontinue the inflammatory response are generated within other white blood cells (lymphocytes, monocytes/macrophages
important to remember
Mast cell- inflammatory mediator-goes straight to site of injury-produces and releases other inflammatory mediators needed to be present/first responder/like (EMS)/closest to site will respond-
leucocytes-term for white blood cell-our protectors-respond to injury
Basophil-contains granulum-get inflamatory process going
Have to have sufficient amount of platelets to clot/needed to heal/forms a scab
inflammatory mediators within platelets
Active in generating and releasing mediators to promote vasodilation, clotting, attraction of white blood cells, ad healing of injured tissues
Histamine, found in white blood cells, housed in platelets
Serotin: causes vasodilation
Histamine-substance found in white blood cells-same as taking (allergy)-anti-histamine-HISTAMINE is present when injury takes place
Serotin: causes vasodilation-comes fast
inflammatory mediators within endothelial or injured tissue
Mediators can be released from these sources
Platelet-activating factor: key role in promoting vessel vasodilation, clotting and attracting infection-fighting white blood cells to the site of injury
Corticosteroids: anti-inflammatory drugs that decrease the inflammatory process and inhibiting the immune response
inflammatory mediators within plasma
Mediators circulate continuously within blood plasma
Pathways responsible for the activation and deactivation of inflammatory mediators that circulate in the plasma – summary on next slide
IMPORTANT
Proteins are triggered in liver -start process of mediating inflamation -clotting-starts clotting cascade Vasoactive inflammatory mediators -summary
important info
Leukocyte
When you have an inflammatory process you have leukocytosis-elevated white blood cells
White blood cells-body’s protector
Too many white blood cells- infection or even strenuous exersice
Decreased white blood cell count-means something serious! You will not be able to fight infection
Neutrophil-first white blood cell on scene-short lived! If present injury happened recently
White blood cell differential-breaks down type of WBC
Macrophage-bigger cell-lives longer-seen mostly in chronic infection-live longer-
Eryhtrocyte-carried in blood, carried oxygen, someone who doesn’t do well in surgery would be an anemic person… person has problems delivering oxygen to areas in blood
Platelets-BLEEDING-low platelet counts patient will bleed to death, needed for healing
three steps for successful cellular response
Chemotaxis: process of moving certain cells to the site of injury
Cellular adherence: blood cells constantly moving through the vascular system, attraction and binding is essential for effective phagocytosis
Cellular migration: the cellular response depends on the ability of cells, primarily leukocytes, erythrocytes and platelets, to migrate to the exact site of injury
-Chemotaxis-process of moving certain site
Cellular adherence- essentail for phagocytosis
Cellular migration-if cells have ability to move
B lymphocytes
Matured in the bone marrow
Essential in mediating adaptive humoral immunity
Production of antibodies/immunoglobins
Account for 10-20% of blood lymphocytes
Lymphocytes-form into two separate categories-T cells and B cells
Start in bone marrow- B cells are very important in HUMORAL IMMUNITY-important in forming anitbodies
cytokinesis
More than a hundred distinct cell proteins
Proteins found within the white blood cell
Vital role in regulating in regulating inflammation
Active from the onset of vasodilation and increased permeability to the resolution of the inflammatory response
Each released from a specific cell and serves a specific purpose
-Proteins found in WBC-vital role in inflammation
CYTO-active in process to beginning to resolution
EACH CELL RESPONDS IN A CERTAIN WAY TO A CERTAIN INJURY
inflammation summary
Tissue injury Blood vessel vasodilation Increased vascular permeability Activation of the clotting cascade Continued release of vasoactive inflammatory mediators -Vascular inflammatory-dilation and permeable REMEMBER Purpose of inflammatory mediators And how many are there
Leukocyte
Different types of white blood cells (WBCs):
Neutrophils
Monocytes
Macrophages
Mast cells
Basophils
Eosinophils
T and B lymphocytes
Neutrophil-first to arrive-initiates phagocytosis-cleans up area-short lived
Monocytes-come with neutrophil-matures into macrophage-if present process has started maybe a week old
Basophils-acts like mast cell but releases histamine into blood- if Present-possible allergy
Eosinophils-effective in parasites and possibly an allergy
two types of leukocytes
Granulocytes
nongranular