Immune System Flashcards
Define innate immunity
- organs, tissues, & cells of the immune system that you are born with
Define acquired immunity
- immunity that develops during your lifetime
Define active immunity
- develops in response to an infection (natural) or vaccination (artificial)
Define passive immunity
- develops after you receive antibodies from someone (natural through breast milk) or somewhere else (artificial from medicine)
Phases of an immune response
1) recognition (immune system recognizes an intruder)
2) amplification
3) effector phase (removal of antigens)
4) termination phase (immune system stands down)
5) memory (generation of long-lived T- & B-lymphocytes)
Characteristics of innate immunity
- 1st line of defense, managing most threats
- early defense to prevent spread, elimination of pathogens & imitate adaptive immunity
- includes internal & external defenses
External defense mechanisms
- anatomical/physical barriers (skin, mucus, cilia lining, & coughing/sneezing)
- chemical/biochemical barriers ( lysosomes, ear wax, stomach acid, & natural floria of organ systems)
Internal defense mechanisms
- soluble factors (cytokines & chemokines)
- cellular components (phagocytes, neutrophils, monocytes, & natural killer cells)
Describe soluble (inflammatory) mediators
- part of the complement system: biochemical network of more than 30 plasma proteins
- can coat the microorganisms with markers to allow the white blood cells to target them
Define phagocytes
- are white blood cells/leukocytes
- involved in nonspecific or innate immunity
- readily ingesting/killing pathogens
Define granulocytes
- have granular appearance
- short lifespan of 2-3 days
- neutrophils are a granulocyte
Define monocytes/macrophages
- have lifespan of months to years
Describe neutrophils
- derive from bone marrow
- short lived
- predominate leukocytes in the blood
- 1st to arrive at site of infection & significantly increase in number during a response
- attract monocytes
- dies following phagocytosis = pus
Describe monocytes
- large, long-lived cells
- originating from bone marrow
- migrate to tissues following immune response then mature into macrophages (large eaters)
- clean up debris & kill any remaining damaged or large bacteria
- rely on cell-surface receptors
What do eosinophils do
- they respond during allergic reactions
What is the importance of basophils & mast cells
- they are important in allergic response
Describe lymphocytes
- circulate in tissues, peripheral blood, & lymphatic system
- respond to viral infections
- include natural killer cells, B cells, & T cells
Describe natural killer cells
- large lymphocytes, found in blood stream & spleen
- kill viruses, intracellular microbe infected cells, & tumor cells
- function more effectively with helper T cells
- express activating/inhibitory receptors on surface which target cells
Describe dendritic cells (DCS)
- messenger between innate & adaptive immune system
- present in cells in contact with external environment, aka the skin (langerhans cell)
Characteristics of adaptive immunity
- recognizes threat, promotes effective response, destroys threat, & establishes memory
- initiates after innate immunity & develops over lifetime
- creates immunological memory of pathogen to enhance future reaction to the same pathogen
Define antigen
- any foreign material
- examples: bacteria, virus, & parasite
Describe B cells
- arise & mature from bone marrow
- fight bacteria & viruses by making Y-shaped proteins (aka antibodies)
- require support from T cells
Describe antibodies
- they are presented to T cells
- are pathogen specific
- mark cells for destruction
Define plasma B cells
- large cells, produce antibodies in response to a specific antigen attack - effector cell
Define memory B cells
- long-lived cell, rapid response to future attacks
Describe T cells
- originate in bone marrow, travel to thymus for maturation
- each has a specific receptor for a specific antigen and can differentiate into several effector T lymphocyte subsets
What are the 4 types of T cells and what do the do
Helper T cells: activate other immune cells, release cytokines & help B cells produce antibodies, shapes & regulates immune response
Killer T cells: releasing cytotoxic granulates into target cell to kill a specific target antigen
Memory T cells: long-lived, form following an infection, proliferate quickly upon re-exposure
Regulator/Suppressor T cells: shut off the immune response when no longer needed
Define humoral immunity
- also considered B cell immunity
- pathogen located in blood plasma & lymph, free floating & easily accessed
- bacteria & virus
- creates specific antibodies & immunoglobulins, B cells differentiate & proliferate into plasma cells & memory B cells
Define cell mediated immunity
- also considered T cell immunity
- pathogen located in cell, destroy microbes in cytoplasm or phagocytic vesicles of infected cells
- bacteria, virus, protozoa, parasite, or cancer
- can be harmful to the host, rejection & autoimmune disorders
Define primary immune response
- the first time an antigen is introduced to the body
- 10-17 day lag between initial exposure & an effect from the immune system
Define secondary immune response
- subsequent exposure to the same antigen
- the response is faster (2-7 days) with greater magnitude
- antibodies in the secondary response have a greater affinity for the antigens
Factors that alter the immune system
- age
- medications
- nutrition
- environmental pollution
- exposure to toxic chemicals
- trauma
- burns
- sleep disturbance/stress
- presence concurrent illness/disease
- splenectomy
Factors that increase exposure to pathogens
- urinary catheters
- nasogastric tubes
- endotracheal tubes
- chest tubes
- PICC line
- external fixation devices
- implanted prostheses
- social & sexual practices
What is the Wear & Tear Theory
- organs composed of cells that cannot regenerate will eventually “wear out”
What is the Genetics theory
- aging is genetically determined
What is the Oxidative (free radical) theory
- based on chemical nature & wide presence of free radicals causing DNA damage & cellular oxidative stress
What is the Telomere Aging Clock Theory
- telomere act to signal onset of cell senescence
Changes to innate immunity due to aging
- exterior defenses are affected by thinning if the skin
- phagocytes (neutrophils & monocytes/macrophages) show a decrease in function with aging
- eosinophils accumulate in fewer numbers at sites if infection with age
- basophils are characterized by reduced degranulation with aging
Changes in acquired immunity due to aging
- difficulty mounting protective immune responses to newly encountered antigens due to decreased production of T & B cells
Define psychoneuroimmunology
- study of interaction between psychological processes & nervous/immune systems of the body
How does stress alter your immune response
- when physically or emotionally stress, your body releases epinephrine & cortisol which increase the production of pro-inflammatory cytokines which are typically released in response to an infection or injury
How can exercise enhance the immune system
- immune system is enhanced during moderate exercise
- prevents neuroendocrine & detrimental immunologic effects of stress
How can exercise suppress the immune system
- with prolonged/intense exercise it suppresses lymphocytes which suppress natural killer cell activity & oxidative modifications of DNA impairment
What is important to know about exercise & infection
- exercise during the incubation period of the infection appears either to have no effect or to increase the severity of infection
-intense exercise in young subjects causes suppression of the immune system but not for aged populations
What is important to know about exercise & infection
- exercise during the incubation period of the infection appears either to have no effect or to increase the severity of infection
-intense exercise in young subjects causes suppression of the immune system but not for aged populations
How to determine whether to exercise during a viral/bacterial infection
- if symptoms (sx) are located above the neck, exercise cautiously at half speed & after 10 min if sx alleviate then resume usual exercise
- if symptoms (sx) are located below the neck, exercise should not be initiated for 7-14 days bc of risk of dehydration, prolonged illness, or more serious complications
