The Immune System and Innate Defenses Study Guide Flashcards
Pathogen
a potentially harmful microbe-bacteria, viruses, fungi etc
organs or tissues borrowed from other systems and used for their immune functions
Skin, spleen, tonsils, bone marrow, thymus, lymph nodes, mucous membranes
1st line of defense
a surface barrier
- skin
- mucous membranes
- secretions of skin and mucous membranes
2nd line of defense
internal defenses that act when the 1st line is broken
- phagocytic cells
- natural killer cells
- antimicrobial cells
- inflammatory response
- fever
3rd line of defense
slower to mount but acts with more precision and efficacy
- lymphocytes
- antibodies
- macrophages and other antigen-presenting cells
protective chemicals from the 1st line of defense
- Acid to inhibit bacterial growth
- Enzymes (Example: Lysozyme) to destroy bacteria
- Mucin to trap microbes
- Defensins to control bacterial growth in exposed areas
4 cardinal signs of inflammation
Redness, heat, swelling, and pain
What types of leukocytes are phagocytes
Neutrophils are the most abundant phagocytes
What purposes does inflammation serve?
- Prevent the spread of damaging agents to the nearby tissue
- Dispose of cell debris and pathogens
- Alert the adaptive immune system
- Set the stage for tissue repair
what types of leukocytes are Natural Killer Cells?
NK cells are a type of lymphocyte that are less picky than the ones of the adaptive immune system – they can kill cancerous/virus infected cells before adaptive immune system is activated
type of leukocyte that can differentiate into a macrophage when activated
monocytes
opsonization and why it’s useful
- “To make tasty” – accelerates phagocytosis
- The immune system coats a pathogen with opsonins – complement proteins or antibodies – to obtain a place to bind – the opsonins allow the phagocyte and the pathogens to bind
cell organelle that plays a key role in phagocytosis
Lysosomes and phagosomes (form lyso-phagosomes)
steps of phagocytosis
- Phagocyte adheres to pathogens
- Phagocyte engulfs the particles, forming a phagosome
- Lysosome fuses with the phagocytic vesicle, forming a phagolysosome
- Lysosomal enzymes digest the pathogens or debris, leaving a residual body
- Exocytosis of the vesicle removes indigestible and residual material
When pathogens cannot be killed with lysosomal enzymes ….
Helper T Cells trigger macrophages to produce “respiratory burst” - cell-killing free radicals, oxidizing chemicals, pH/osmolarity changes
two functions of a fever
They sequester iron and zinc – minerals needed to support bacterial growth – and increasing the metabolic rate of tissue cells completing repair processes
3 inflammatory mediators
Histamine, kinins, prostaglandins (like nitric oxide), complement proteins
phagocyte margination
Phagocytes cling to the inner walls of capillaries and postcapillary venules to indicate the place of injury
type of antimicrobial protein most effective against viruses
Interferons are most effective against viruses – they are secreted by virus infected cells and protect nearby uninfected cells by slowing down protein synthesis
type of antimicrobial protein most effective against bacteria
Complement proteins are most effective against bacteria – they are a group of about 20 plasma proteins circulating the blood, when activated they will amplify nearly all aspects of the inflammatory process, and they can lyse (kill) certain cells and bacteria
What is the body’s internal thermostat and the substance that is involved in the body’s temperature?
The hypothalamus is the body’s thermostat – pyrogens act on it to raise the body’s temperature
