Immunology Flashcards
What is immunity?
Resistance to a disease, specifically infectious disease
What is the immune system?
The collection of cells, tissues, and molecules that mediate resistance to infections
What is an immune response?
The coordinated reaction of the cells and molecules to infectious microbes
What is the physiologic function of the immune system?
To prevent infections and eradicate established infections
How many lines of defense fir the immune system are there ?
3 lines of defense
Differentiate the first 2 lines of defense of the immune system from the 3 rd line of defense
First 2 lines of defense are nonspecific or innate
3rd line of defense, the immune response, is very specific or adaptive
-In the 3rd line of defense, special proteins called antibodies are produced in response to foreign substances called antigens
What line(s) of defense are innate/intrinsic ?
First and second line
What lines of defense use acquired/adaptive immunity?
3rd line of defense
Describe an innate response
First and second response is immediate to “new” and “repeat” invaders (non-specific)
Describe an adaptive response
Third response is delayed and highly specific in response to “new” invaders. Memory cells can respond to “repeat offender” rapidly
Describe the first line of defense?
-Skin and Mucous membranes as MAJOR physical barriers
- Cellular and Chemical factors
- pH, temperature, perspiration, cilia, and secreted enzymes
- Microbial Antagonism
- When indigenous microflora prevent colonization of “new arrivals” as a result of competition for sites and nutrients and production of lethal substances
What 8s microbial antagonism?
-When indigenous microflora prevent colonization of “new arrivals” as a result of competition for sites and nutrients and production of lethal substances
Part of the first line of defense
What is the second line of defense?
The compliment system
A group of about 30 different proteins found in normal blood plasma including C3-“complementary” to the immune system
Complement components interact with each other in a stepwise manner known as the complement cascade, including cleavage of C3 to C3b (bound version)
-Opsonization is a process by which phagocytosis is facilitated by the deposition of antibodies or C3b onto microbes
What is opsonization ?
-When indigenous microflora prevent colonization of “new arrivals” as a result of competition for sites and nutrients and production of lethal substances
What is the second line of defense ?
Complement system(comeback to 9/65)
Cytokines
What are cytokines?
Chemical mediators released from manu different types of cells in the body; enable cells to communicate with each other- within the immune system and other systems of the body
-second line of defense
What are interferons?
Type of cytokines
-small, antiviral proteins produced by virus-infected cells; they prevent viruses from multiplying
Interferons are virus specific, but they are species specific
-interferons can cause nonspecific “flu-like” symptoms
What are the types of interferons?
- Alpha
- beta
- Gamma
Produced by 3 different types of cells
What are phagocytes?
Phagocytic white blood cells and use a process by which they surround and engulf (ingest) foreign material is called phagocytosis
What are the types of white blood cells (leukocytes)?
The 3 major categories of leukocytes (white blood cells) found in blood are monocytes, lymphocytes and granulocytes
The 3 types of granulocytes are: eosinophils, basophils and neutrophils
The most important groups of phagocytes in the human body are macrophages, neutrophils and dendritic cells
What are the functions of Macrophages?
They are resident in the tissues and are the first responders to infection
- recognize pathogens via Toll-like receptors
- Phagocytosis
- Cytokine production
- Antigen presentation of intracellular bacteria to CD4+ T cells
- Tissue repair
What are the functions of Neutrophils?
- Recognize pathogens via receptors
- Phagocytose microbes and destroy them with the toxic contents of the neutrophil granules, especially extracellular bacteria and fungi
- Kill microbes with enzyme-rich granules and Reactive Oxygen Species (ROS)
- Die within hours, responsible for pus formation (pyogenic infection)
What are the Natural Killer cells (NK)?
- NK cells are in a sub population of lymphocytes
- They resemble lymphocytes, but lack typical T or B cell surface markers
- Do not proliferate in response to antigen and appear not to be involved in antigen-specific recognition
What are the functions of NK cells?
NK cells kill target cells, including foreign cells, host cells infected with viruses or bacteria, and tumor cells