Immunology & Immunizations Flashcards
Describe the lines of defense of the immune system
First: (innate) external skin/mucosal membranes
Second: (innate) antimicrobial proteins, phagocytes, other cells that inhibit spread of invaders & trigger inflammation
Third: adaptive immune system
Describe how the surface barriers protect us against microorganisms
- protective chemicals that inhibit/destroy
- mucus-coated cilia in the respiratory tract sweep microorganisms from lower respiratory passages
- organ surfaces participate
Describe the internal defenses of the immune system
cells and chemicals
- phagocytes
- NK cells
- inflammatory response (macrophages, mast cells, WBCs, chemicals)
- antimicrobial proteins (interferons)
- fever
Describe phagocytes
type of cell that engulfs and absorbs bacteria, small cells, particles
Describe macrophages
- develop from monocytes
- chief phagocytic cells of the immune system
- free macrophages wander through tissue space
- fixed macrophages are permanent residents of some organs
Describe neutrophils
become phagocytic upon encountering infectious material in tissues
Describe Natural Killer cells
- large granular lymphocytes
- 2 types of receptors (inhibitory recognize self, activating recognize stressed/infected cells)
what are the cardinal signs of acute inflammation
redness, heat, swelling, pain (sometimes impairment of function)
What are the inflammatory mediators
- histamine
- blood proteins
- kinins
- prostaglandins
- leukotrienes
- complement cells
(released by injured tissue, phagocytes, lymphocytes, basophils, mast cells)
Describe the vascular permeability step of the inflammatory process
inflammatory chemicals cause vasodilation resulting in hyperemia & increased permeability & edema of local capillaries that produces exudates (proteins, clotting factors, antibodies)
Describe how edema works in the inflammatory response
- results from surge of exudates
- moves foreign materials into lymphatic vessels
- delivers clotting proteins to form a scaffold for repair and isolate the area
Describe the main points of th einflammatory response
- triggered when body tissues are injured/infected
- prevents spread of damaging/infectious agents
- disposes of cell debris & pathogens
What are the 5 leukocytes
Granulocytes (PMNs)
- eosinophils
- neutrophils
- basophils
- lymphocytes
- monocytes
What are the 4 steps of phagocyte mobilization
- leukocytosis: release of neutrophils
- margination: neutrophils cling to capillary walls
- diapedesis: neutrophils pass through
- chemotaxis: inflammatory chemicals promote positive chemotaxis of neutrophils
What do complement proteins do
major mechanism for destroying foreign substances (viral infection)
- consist of 30+ blood proteins that circulate in an inactive form
describe an interferon
Function
- antiviral
- reduce inflammation
- activate macrophages & mobilize NK cells
Describe a fever
- systemic response to invading microorganisms
- leukocytes & macrophages exposed to foreign substances secrete pyrogens
- pyrogens increase the body’s thermostat
- high fevers can denature enzymes
- moderate fevers can increase metabolic rate/repair & sequester iron & zinc in the liver
Describe adaptive immunity
- specific, systemic, memory
- Humoral immunity: antibody mediated (B cells)
- cellular immunity: cell mediated (T cells)
Define an antigen
- toxin or foreign substance that induces an immune response & production of antibodies
- most are large, complex molecules not normally found in the body
Describe B and T lymphocytes
cells of the adaptive immune system
- B (humoral): responsible for creation of antibodies once an antigen provokes a humoral response, mature in red bone marrow
- T (cell-mediated): proliferate & differentiate into effector cells of immunity & helper cells for antibody response by secreting cytokines, mature in thymus, mature = immunocompetence & self-tolerance
recognize and bind to antigens, communicate with each other to mount a specific immune response to destroy non-self substances
Describe a primary immune response
- occurs on first exposure to an antigen
- lag period of 3-6 days
- peak levels of plasma Ab reached in 10 days
- Ab levels slowly decline
Describe a secondary immune response
- occurs on re-exposure to an Ag
- sensitized memory cells respond within hours
- Ab levels peak in 2-3 days at much higher levels than primary response
- Abs bind with greater affinity
- Ab level can remain high for weeks/months
Describe active humoral immunity
When B cells encounter Ags & produce specific Abs against them
Two types
- Naturally acquired: response to bacterial/viral infection
- Artificially acquired: response to a vaccine of dead/attenuated pathogens