Ch. 26 - Innate Immunity: Broadly Specific Host Defenses Flashcards
(22 cards)
What are the human body’s 3 lines of defense?
First line of defense keeps pathogens outside or neutralize them before infections begin. (Skin, mucous membranes, antimicrobial agents)
Second line of defense slows or contains infections when the first line fails (inflammation, fever, phagocytes, NK cells)
Third line of defense are WBCs that target specific pathogens for destruction (memory component that remembers pathogen. Humoral and cellular immunity)
What are the 3 innate WBCs?
Basophil
Eosinophil
Mast cells
Basophil
Granulocyte that releases histamines that causes inflammation.
Eosinophil
Granulocyte that kills parasites with oxidative burst.
Mast cells
Agranulocyte that kills infected cells (often virus-infected) via cytolysis or apoptosis)
What are 4 WBCs that are part of innate and adaptive immunity?
Neutrophil
Monocyte
Dendritic cell
Natural killer (NK) cell
Neutrophil
A granulocyte that phagocytizes bacteria and fungi.
Monocyte
Agranulocyte that is a precursor to macrophages. Some macrophages are fixed in certain organs while other wander tissues causing inflammation. All perform phagocytosis.
Dendritic cell
Many surface projectiles in the skin, respiratory, and intestinal mucosa that phagocytizes bacteria and presents antigens to T cells.
Natural killer (NK) cell
Agranulocyte (LYMPHOCYTE) that kills cancer cells and virus-infected cells.
What are the 3 adaptive WBCs?
Natural killer cells
Plasma cell, B cells
T cells (T helper cell, Cytotoxic T lymphocytes, T regulatory cell)
Plasma cell, B cell
Agranulocyte (LYMPHOCYTE) that recognizes antigens and produces antibodies.
T cells
T helper cell, Cytotoxic T lymphocyte, T regulatory cell
Agranulocyte:
T helper cells secrete cytokines. They are CD4+ cells that bind MHC class II molecules on antigen-presenting cells.
CTLs recognize and kill specific “non self.” They are CD8+ cells that bind to MHC class I molecules.
T regulatory cells that do not correctly recognize “self” cells.
Immunity (resistance)
Immunity or resistance is the ability to ward off disease.
Immunity (susceptibility)
Lack of resistance to a disease
Innate immunity
Innate immunity is present at birth. It is a rapid dense mechanism against ANY pathogen.
Adaptive immunity
Immunity or resistance to a specific pathogen. It is slow to respond and has a memory component. It is acquired throughout our lifetime.
Innate immunity
An immune system that you’re born with. It includes physical barriers, phagocytosis cells, inflammation and fever. It is non-specific (defined pathogens are not targeted). It represents the first and second lines of defense.
Adaptive immunity
It is acquired throughout life. It targets specific pathogens resulting from prior exposure and memory. It represents the third line of defense when the innate immune system fails to stop the pathogen.
List the differences between innate immunity and adaptive immunity.
Innate immunity: immediate non-specific response. The response is the same regardless of the pathogen. It does NOT require previous exposure and has a noninducible ability to recognize and destroy an individual pathogen.
Adaptive immunity: slow to develop, but a very specific response. It depends on previous exposure to the pathogen and is directed toward an individual molecular component of the pathogen (antigen).
What is natural host resistance?
It is normal microbiota that helps the host resist pathogens (particularly on the skin & gut d/t COMPETITIVE EXCLUSION). However, the ability of microbes to cause disease varies between species.
Note: competitive exclusion states that 2 species cannot coexist in the same ecological niche for long d/t competition for limited resources.
Why is the infection site considered a barrier to pathogenic invasion?
The infection site is crucial in determining the routes of infection. Also, different pathogens invade different tissues.
