Topic 6 (Unit 4) Flashcards
Define antigen.
“Antibody generating.”
Any foreign molecule leading to the production of antibodies.
Define antibiotic
A type of antibacterial compound.
Bacteria specific drug that slows or prevents bacterial reproduction.
Define lymphatic system
Composed of lymph nodes and lymphatics.
Drains tissue fluid back into normal circulation.
Define lymph
Liquid that drains away from the tissue fluid cells into lymph vessels.
Contains a high number of lymphocytes.
Define leukocyte.
White blood cell.
Cells capable of amoeboid movement.
Includes phagocytes and lymphocytes.
Define lymphocyte.
Type of white blood cell involved in adaptive immunity. Produced in the bone marrow and matures either as a B cell or T cell.
Define lysozyme.
Enzyme produced in body secretions that digest peptidoglycan in bacterial cell walls.
Define phagocytosis
A form of endocytosis carried out by some white blood cells.
Define lysosome.
Vesicle containing hydrolytic enzymes.
Define phagosome
Formed during phagocytosis through the fusion of a lysosome and foreign matter
Define epidemiology
The study of how often diseases occur in different groups of people and why.
Define immune
Protection from a pathogen or disease.
Presence of or the ability to produce large numbers of specific antibodies in the blood.
Define 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.
Define specific immune system
Kills invading pathogens, but also remembers the pathogens feature’s so that it can be killed quickly on subsequent infections.
Only vertebrates have specific immunity.
Define self/non-self recognition
Ability to detect and produce antibodies against foreign antigens and not against own cells.
Define antibody mediated
A.K.A. Humoral
Type of specific immunity conducted by B cell produced antibodies against antigens identified as non-self.
Commonly used against bacteria, fungi and free virions.
Define cell mediated
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, this 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 the presentation of fragments on the cell surface to lymphocytes.
Define MHC
Major histocompatibility complex.
Extrinsic cell proteins that present fragments of proteins on the surface for self/non self recognition.
What is the first line of protection humans have against invading pathogens?
Barriers.
The skin and associated chemicals stop microbes entering the body.
What is the second line of protection 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 protection 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
A.K.A. Non specific.
Refers to non specific defense mechanisms that come into play immediately or within hours of an antigens appearance in the body.
Define adaptive
A.K.A. Specific
More complex than innate.
Antigen is processed and recognised leading to the creation of an army of immune cells.
Has memory.
Define active immunity
Immunity provided by the organism’s own cells
Define passive immunity
Immunity acquired from the cells of another organism
What are the two main functions of the lymphatic system?
- Return tissue fluid to circulation.
2. Fights infection (both specific eg B cells and non-specific resistance eg complement)
Primary lymphatic organs are involved in…
The production and/or maturation of leukocytes and lymphocytes.
Eg red bone marrow, thymus
What is the function of secondary lymphatic organs?
Store lymphocytes and help to filter lymph of dead cells or debris before returning it to circulation.
Eg lymph nodes, spleen
Where are leukocytes manufactured?
Bone marrow tissue
Is the greater population of leukocytes found in blood only lymph?
Lymph
What are the leukocytes involved in phagocytosis called?
Macrophages / monocytes
Neutrophils
What is the distinguishing feature of monocytes / macrophages
Ability to engulf and destroy debris and pathogens by phagocytosis.
The action of macrophages is regulated by…
The presence of receptors that can interact with T lymphocyte cells.
How do macrophages move?
By amoeboid movement using pseudopods.
The presence of a CD4 receptor protein means that macrophages are…
Susceptible to HIV infection
The characteristic appearance of a neutrophil is due to…
A multilobed nucleus
How are neutrophils attracted into a tissue?
The release of proteins called cytokines (the most famous of which is interferon).
These molecules are detected by receptors in the membrane.
T cell derived chemicals affect the migration of neutrophils. This is an example of….
Chemotaxis.
What is the neutrophils main role?
Inflammation.
They are the first cells to arrive at the site of inflammation by leaving the blood through the capillary walls - a process known as diapedesis.
Define antibody.
Protein molecule produced by B cells in response to antigen.
