Overview Immuniology Flashcards
Immunology is the study of what?
The study of the ways the body resists infection
Innate Immunity
(Non-specific Immunity)
“you are born with it”
First Line Defense:
1.1 Skin – unbroken skin prevents microbes from entering the body
1.2 Mucous membrane with cilia in the respiratory tract – traps inhaled dust, dirt and pathogens
1.3 Digestive secretions of the stomach and intestines
1.4 Phagocytosis – neutrophils, eosinophils, macrophages, histocytes 1.5 Inflammatory Response – swelling, redness, heat and pain - prevents the spread of the pathogen - localize and contain the infection - contain and neutralize the toxins - to aid in the repair of damaged tissues 1.6 Peristaltic movement of the GI Tract 1.7 Flushing action of urination 1.8 Vaginal mucosal secretions
Second Line Defense
2.1 Complement – a group of plasma proteins that aid in the lysis of bacterial cells
2.2 Interferon – proteins produced by leukocytes, inhibits the spread of viral infection
- “interfere” withviral replicationwithin host cells
Acquired Immunity
(Specific Immunity) – “you acquire it” - immunity brought about by production of specific antibodies/cells that protect against pathogens
Antibodies
protective proteins produced by white blood cells as a reaction to the presence of an antigen
Natural Active Immunity
production of antibodies by the host after natural/non-deliberate exposure to the disease
Example: immunity against German measles after
having one
Artificial Active Immunity
antibody production by the host stimulated by deliberate exposure to the antigen (as in vaccination)
Natural Passive Immunity
naturally produced antibodies of one individual are passed on to another susceptible individual
Example: antibodies from the mother to the offspring through the placenta or through breast milk
Artificial Passive Immunity
antibodies from animals or human beings prepared in the laboratory (artificially produced) are injected to a susceptible individual
Example: commercially prepared anti-rabies antibodies injected to a patient after a bite from a potentially rabid animal
Types of Vaccines
- Live Attenuated Vaccine – contains live but weakened or less virulent forms of the pathogen
Example: measles vaccine * - Killed Inactivated Vaccine - contains non-living or inactivated pathogens
Example: Flu vaccine - Toxoids – contain toxins of the pathogen
Example: Tetanus vaccine - Extracts of pathogens (such as bacterial capsule of pathogens)
Example: Pneumococcal vaccine
attenuate
to weaken, to lessen the effect
Humoral Immunity an immune response
production of antibodies upon exposure to an antigen
Antibodies = Y-shaped protective proteins produced by white blood cells (B-Lymphocytes) as a reaction to the presence of an antigen
B-Lymphocytes or B cells – formed in the bone marrow and moves directly to the lymph nodes and spleen where they survey for invading pathogens
Cell-mediated Immunity an immune response
production of T- lymphocytes, macrophages and natural killer cells that directly attack pathogens and cancer cells.
T-lymphocytes or T-cells – formed in the bone marrow then migrate and mature in the thymus.
Process of Infection
*Generally do not cause disease
Resident Flora (Normal Flora)*– organisms that normally live in and on the bodies of healthy persons without causing harm when located in specific sites
Example: Staphylococcus – skin
Transient Flora* – organisms that take up residence in or on the body temporarily in a location where they are not normally found
Example: Escherichia coli – skin
Opportunistic organism – a resident organism that has multiplied way beyond its normal number and has caused disease
Opportunistic infections are likely to occur when host resistance is lowered
Example: Staphylococcal infection in a surgical site
Infection
An invasion of the body by organisms and the reaction of the body to the presence of those organisms and to the toxins they produce
The presence of and multiplication of an organism that results in harm or disease to a host
Disease - a specific illness or disorder characterized by a recognizable set of signs and symptoms
- attributable to infection, heredity, diet or environment
Host - an organism that serves as a permanent or temporary home for another organism
Example: Human host of a bacterial infection
Toxin - a substance that is harmful to host cells
Example: toxins from syphilis, tuberculosis, staphylococcus
Portals of Entry total 6
Specific pathways by which a microorganism enters the body that result in an infection
May be a natural opening (such as the mouth), or an injury (such as a cut, surgical incision)
- Skin – must be broken to act as a portal of entry
Examples: opportunistic staphylococcus, streptococcus, tetanus - Respiratory Tract – the most common route of infection
Examples: tuberculosis, pneumonia, common cold - Alimentary Tract – through the mouth by contaminated food or water
Examples: typhoid fever, hepatitis A, amoebic dysentery, cholera - Genito-urinary Tract – through the urethra and/or the reproductive tract
Examples: organisms causing UTI, STDs (gonorrhea, genital herpes, genital warts, HIV)
Urinary infections are usually the result of migration of microorganisms from the rectal area - Placenta – from mother to fetus
Examples: syphilis, HIV - Circulatory System – through the bloodstream by contaminated blood transfusion, needle pricks, cuts from contaminated objects, insect bites
Examples: Hepatitis B, HIV- insect bites: malaria, dengue fever
Portals of Exit
. Pathway by which microorganisms leave the body
. All body secretions and excretions (except for sweat) may be portals of exit
. Infections spread to others through portals of exit
- Respiratory secretions (sputum) – tuberculosis, pneumonia, common cold
- Saliva – streptococcal sore throat
Saliva from animals can be transmitted to humans
Example: rabies
- Blood - Hepatitis B, HIV
- a major concern for health care workers
- Feces - Hepatitis A, typhoid fever, amoebic dysentery
- Urine - typhoid fever, organisms causing UTI
- Semen and vaginal secretions – STDs
- Other portals of exit: tears, amniotic fluid, cerebrospinal fluid, vomitus, synovial fluid
Carriers
hosts who have recovered from a disease (or who are incubating the disease), who are asymptomatic, may still transmit the disease to others
Zoonosis
diseases that are communicable from animals to man