Immune System Flashcards
What is a pathogen?
A disease-causing organism, such as a virus, bacteria, protozoa, or fungus
The scientific study of pathogens is called Pathology.
What are the characteristics of bacteria?
Prokaryotes, divide by binary fission, can cause diseases such as:
* Food poisoning (e.g. Salmonella)
* Ear and eye infections
* Strep throat
* Cholera
* Diarrhea
What is a virus?
Acellular, requires a host cell for life functions, can have DNA or RNA, cannot be killed by antibiotics, mutates quickly
Causes diseases such as flu, HIV, smallpox, measles, common cold, herpes, and ebola.
What are fungi?
Eukaryotes that reproduce with spores, cell walls contain chitin, can cause:
* Athlete’s foot
* Mould
* Ringworm
* Vaginal candidiasis
* Allergic reactions and respiratory problems
What is protozoa?
Unicellular eukaryotes that can be parasitic or symbiotic, causing diseases like:
* Malaria
* Leishmaniasis
* Toxoplasmosis
* Giardia
* Lyme’s disease
What are helminthic parasites?
Multicellular eukaryotic parasites that can cause:
* Elephantiasis
* Schistosomiasis
* Toxocariasis
* Pinworm
* Roundworm or tapeworm infections
How can pathogens be transmitted?
Through:
* Inhaled droplets
* Direct contact
* Bodily fluids
* Animal vectors
* Blood contact
* Ingestion
What is innate immunity?
Nonspecific defense mechanisms that come into play immediately or within hours of an antigen’s appearance
Includes physical barriers and macrophages attacking pathogens.
What is adaptive immunity?
Specific defense mechanisms using antibodies
Includes active immunity (produced by the organism) and passive immunity (acquired from another organism).
What are the two layers of skin?
The dermis (underneath layer) and the epidermis (outer layer)
The epidermis mainly consists of dead cells that provide a barrier against pathogens.
What role does stomach acid play in pathogen defense?
Kills pathogens that enter the body through food and water due to its acidic environment.
What is the process of blood clotting?
Involves:
* Platelets and damaged tissue release clotting factors
* Conversion of prothrombin into thrombin
* Thrombin catalyzes conversion of fibrinogen into fibrin
What are the two types of lymphocytes?
B cells and T cells
B cells produce antibodies, while T cells mediate B cell activity and destroy virus-infected cells.
What is phagocytosis?
The process by which macrophages engulf and digest invading pathogens.
What is a primary immune response?
The initial response to a novel pathogen, involving non-specific immune response and antibody production.
What triggers antibody production?
Antigens, which are substances or molecules found on cell or virus surfaces.
What is clonal selection?
The process by which activated B cells divide to produce clones of plasma cells that secrete the same antibody type.
How do memory B-cells function?
Remain inactive until the same pathogen infects the body again, allowing for a rapid immune response.
What is humoral immunity?
The pathway by which antibodies are produced by B lymphocytes to target exogenous antigens.
What is cell-mediated immunity?
Targets endogenous antigens, involving cytotoxic T cells that bind to and kill infected or cancerous cells.
What is antigen presentation?
The process where a macrophage engulfs a pathogen and presents its antigen to a Helper T-cell via MHC proteins.
What are plasma cells?
Mature B lymphocytes that secrete a large number of antibodies during an immune response.
Plasma cells are crucial for the adaptive immune response, producing antibodies that target specific pathogens.
What is the primary immune response?
The initial response to a novel pathogen, involving non-specific immune response and antibody creation.
Symptoms of disease typically develop during this response due to the time it takes for the body to produce antibodies.
What is the secondary immune response?
The response to a second or subsequent exposure to a pathogen, characterized by rapid antibody production from memory B cells.
This response is usually faster and produces more antibodies than the primary response.