Flashcards in Immunity Deck (50)
What is an antigen?
Any foreign molecule leading to the production of antibodies.
What is an antibiotic?
A type of antibacterial compound.
Bacteria-specific drug that slows or prevents bacterial reproduction.
What is the lymphatic system?
Composed of lymph nodes and lymphatics.
Drains tissue fluid back into normal circulation.
Liquid that drains away from the tissue fluid cells into lymph vessels.
Contains a high number of lymphocytes.
What are leukocytes?
White blood cells.
Capable of amoeboid movement.
Includes phagocytes and lymphocytes.
What are antibodies?
Protein molecules produced by B cells in response to an antigen
What are lymphocytes?
A type of white blood cell.
Involved in adaptive immunity.
Produced in the bone marrow and mature as either B cells or T cells.
What is lysozyme?
Enzyme produced in body secretions.
Digests peptidoglycan in bacterial cell walls.
What is phagocytosis?
A form of endocytosis carried out by some white blood cells.
What is a lysosome?
Vesicle containing hydrolytic enzymes
When is a phagosome formed?
During phagocytosis through the fusion of a lysosome and foreign matter
What is epidemiology?
The study of how often diseases occur in different groups of people and why.
Protection from pathogens/disease.
Presence of, or the ability to produce, large numbers of specific antibodies in the blood.
What is a vaccine?
Sample of antigen that increases immunity.
Gives the ability to produce, or increases the amount of, specific antibodies in the blood.
Define "herd immunity"
Protection of vulnerable non-immune individuals in a population due to a high level of immunity in the population as a whole.
What is the specific immune system?
Kills invading pathogens, but also remembers the pathogen's features so that it can be killed quickly on subsequent infections
Only vertebrates have specific immunity.
What is self/non-self recognition?
The ability to detect and produce antibodies against foreign antigens and not against the organism's own cells.
Define "antibody mediated"
A type of specific immunity conducted by B cell produced antibodies against antigens identified as non-self.
Commonly used against bacteria/fungi/free virions.
Define "cell mediated"
A type of specific immunity coordinated by T cells.
Commonly used against invaders present in cells.
Define "clonal selection"
Lymphocytes sensitive to antigen reproduce much more rapidly than others, leading to a build up of antigen specific cells large enough to mount an immune response. (PLASMA cells)
Define "antigen presentation"
Consists of ingestion and partial digestion of the antigen by an antigen presenting cell - followed by presentation of fragments on the cell surface to lymphocytes.
What is MHC?
Major histocompatibility complex.
Extrinsic cell proteins that present fragments of proteins on the surface for self/non-self recognition.
Many features of the immune system reflect...
The evolutionary struggle ("arms race") between microbes and hosts as each tries to overcome the other.
How many lines of protection do humans have against invading pathogens?
What is the first line of defense that humans have against invading pathogens?
The skin and associated chemicals stop microbes from entering the body.
What is the second line of defense that humans have against invading pathogens?
The non-specific immune system
Phagocytes quickly destroy microbes that pass the first line of defense.
What is the third line of defense that humans have against invading pathogens?
The specific immune system
Lymphocytes kill any microbes that pass the second line of defense and remain on guard for future attacks.
Define "innate immunity"
Refers to non-specific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body.
Define "adaptive immunity"
More complex than innate. Antigen is processed and recognized leading to the creation of an "army" of immune cells.