Innate Immunity Flashcards
What is innate immunity?
Non-specific response to pathogens that don’t distinguish one pathogen from the other; rather attempts to block them all
What are the three different types of innate immunity?
Physical barriers, chemical barriers, and cellular defenses
What are types of physical barriers?
Skin
Mucus membranes
Chemical secretions
Micro biome
Mechanical actions
How does the top layer of skin prevent viral infection?
The top layer of the skin is dead and viruses need living cells in order to reproduce
What pH level do sebaceous glands keep the skin at?
3-5 (acidic)
What does the dryness of the skin do?
The waterproof barrier of the skin inhibits growth of many types of bacteria
What do skin’s tight junctions do?
Adhere to the cells tightly and densely so pathogens can’t squeeze through the body
Where can mucous membranes be found?
Eyes, ears, inside the nose and mouth, lips, vagina, urethral opening, and the anus
How does the mucous membrane help the immune system?
Cells create a sticky mucous that traps particles before they can go deeper into the body
What are types of mechanical actions that remove pathogens from the body?
Shedding of skin cells
Mucociliary sweeping
Coughing
Vomiting and Diarrhea
Flushing of Bodily fluids (urine, tears)
What are internal defenses of the innate immune system?
Phagocytic white blood cells
Blood clotting
Fever
Inflammation
What is the 1st line of defense of the innate immune system?
Physical barriers (skin and mucous membranes)
What is the 2nd line of defense of the innate immune system?
Internal defenses
What are the functions of phagocytic leukocytes?
Engulf and digest non-human material
Display molecules from the antigens on their cell surface
Release chemicals that summon more leukocytes to the scene
What is extravasation?
When phagocytic leukocytes circulate into the blood and move into the body tissue in response to infection
What is an example of a chemical damaged tissue releases in order to draw white blood cells to the site of infection?
Histamine
What is the migration of white blood cells to the site of an infection called?
Chemotaxis
What are psuedopodia?
Pseudopodia are temporary cytoplasm-filled projections found in white blood cells that help capture pathogens by phagocytosis
What is the internal vesicle pf a phagocyte called?
Phagosome
What happens when a phagosome is fused to a lysosome?
Forms a phagolysosome that digests the pathogen
What are pathogenic fragments called?
Antigens
What stimulates the third line of defense?
Antigens that may be present on the surface of the phagocyte
What are the 6 steps of Leukocyte Phagocytosis?
Chemotaxis
Recognition and Attachment
Endocytosis
Bacteria within a phagocytic vacuole
Fusion of lysosomes and phagocytic vacuole
Killing and digestion
What is the function of a fever?
To accelerate tissue metabolism and immune defense activity
What are the benefits of a fever?
Increase the production of T-cells
Speed up rate of tissue repair
Increase in heart rate-> faster chemotaxis
What are mast cells?
Localized white blood cells that can be activated to release a wide variety of inflammatory mediators
What are basophils?
a type of white blood cell that circulates throughout the body to defend your body from allergens, pathogens and parasites
What chemical is released by mast cells and basophils when tissue damage occurs?
Histamine
How does histamine help leukocytes get to a certain region?
Causes local vasodilation and increased capillary permeability
What are chemotactic factors?
mediators released by damaged cells that induce unidirectional leukocyte movement by establishing a concentration gradient of the chemotactic factor that increases toward an area of inflammation
What causes fluid release into tissues?
Increased permeability
How are histamines produced?
B lymphocyte comes into contact with the allergen
B cell differentiates into plasma cells and makes antibodies
Antibodies attach and activate mast cells
Histamine is released, which triggers inflammatory response
Why does one get allergy symptoms?
Histamine binds to other receptors in the body causing allergy symptoms
What are the two key components of a blood clot?
Platelets and insoluble fibrin strands
What is the function of clotting factors?
To trigger a chemical cascade which results in blood clotting
What are the steps of blood clotting?
Clotting factors stimulate thrombin release
Thrombin catalyses the conversion of fibrinogen into fibrin
Fibrin forms a mech trap to prevent bleeding
The initial stimulus is amplified to make more thrombin
Exposure to air creates a scab
What changes soluble fibrinogen to insoluble fibrin?
An enzyme named thrombin
What is coronary thrombosis?
The formation of a clot within the coronary arteries
What is atherosclerosis?
Atheromas develop in the arteries and significantly reduce the the diameter of the lumen
Restricted blood flow increases pressure leading to damage
Repaired with fibrous tissue, making the wall lose elasticity
Lesions form called atherosclerotic plaques
Plaque ruptures causing blood clotting
Thrombus dislodges and creates a coronary thrombosis
