Immunology Physiology: Part 1 Flashcards
Organs of the Immune System?
- Tonsils and Adenoids
- Lymph and lymphatic vessels
- thymus
- lymph nodes
- spleen
- appendix
- peyer’s patches
- bone marrow
Where do immune system cells develop?
The liver in the spleen
By what week do immune stem cells develop in the fetus?
ninth week
What becomes the primary source of stem cells in the body?
bone marrow
Where do lymphocytes develop in the body?
2
bone marrow and thymus
What kind of lymphocytes predominate in a new born?
TH2
What kind of lymphocytes predominate in ages?
TH1
What are TH2 lymphocytes?
humoral immune system
T cells respond better to what kind of antigen?
respond better to MHCs that are displaying a protein
B cells respond better to what kind of antigen?
respond better to MHCs displaying polysaccarhide capsules and lipids
What are TH1 lymphoctyes?
cell mediated immune system
What two things impair the immune system? These things are often unrecognized and present as an autoimmune disease
stress
depression
Why does incidence of cancer increase as we age?
immune system begins to wane
-do a worse job of recognizing cancer cells as non-self
What are the two intrinsic systems of the immune system?
Describe them?
3 for each
Innate (nonspecific) defense system
- attacks everything
- not learned
- no memory
Adaptive (specific) defense system
- learned/has memory
- develops as we age
- more system based
What are the surface barriers of the innate immune system?
2
Skin
Mucous membranes
What are the internal defenses of the innate immune system?
5
What are the goals of these defenses?
- phagocytes
- Fever
- NK cells
- Antimicrobal proteins
- Inflammation
Inhibit the spread of invaders
What are the internal defenses of the adaptive immune system?
2
Humoral (antibody mediated) immunity- B cells Cellular immunity (cell mediated)- T cells
What does fever accomplish?
disrupts the metabolism of pathogenic organims/viruses
What do B-cells do?
2
Clean up viruses
Alert other Bcells
What do killer T cells do?
destroy infected cells with cytotoxin
What do helper t cells do?
Call for backup
What do macrophages do?
2
Clean up viruses
Call in the T cells
What is the first and second line defenses in your body?
INNATE
First line = physical barriers
Second line = antimicrobial proteins, phagocytes, and other cells
Through what mechanism do most internal innate defenses attack pathogens?
(most important)
inflammation
What is the third line of defense in the body?
adaptive defense system
Which immune system is faster, innate or adaptive?
innate
adaptive is much faster the second time you encounter the same pathogen
Name some protective chemicals that inhibit or destroy microorganisms through the innate defense system?
5
- Skin acidity (skin is a little acidic)
- Lipids in sebum (glandular secretion) and dermcidin in sweat
- HCl and protein-digesting enzymes of stomach mucosae
- Lysozyme of saliva and lacrimal fluid
- Mucus (GI tract and respiratory- catches dusts, particles, pathogens, with its cilia)
What are some modifications made by the respiratory system that act as innate defenses?
2
Mucus-coated hairs in nose
Cilia and mucus elevator in upper respiratory tract
What cells/substances are part of the inflammatory response?
4
- macrophages
- Mast cells
- WBCs
- Inflammatory chemicals
What are the types of antimicrobial proteins?
2
- interferons
2. complement proteins
What are the chief phagocytic cells in the body?
macrophages
Where do macrophages develop from?
monocytes in the blood
Where are free macrophages found?
4
- Alveolar macrophages
- Sinus macrophages
- Lymph nodes
- Spleen
Give an example of where fixed macrophages are found?
2
Kupffer cells are found in the liver and lymph areas
Microglia in brain
When do neutrophils become phagocytic?
encountering infectious material in tissues
describe the steps in the mechanism of phagocytosis
5
- Adherence of phagocyte to the pathogen
- Pseudopods engulf the particle (antigen) into a phagosome
- Phagosomes fuse with a lysosome to form a phagolysosome
- Invaders in phagolysosome are digested by proteolytic enzymes (acid hydrolase enzymes)
- Indigestible and residual material is removed by exocytosis
What facilitated the adhereance of the phagocyte to the pathogen?
Opsonization
-the coating of a pathogen by complement proteins (or antibodies) marking them for destruction.
Name the steps for phagocyte mobilization
4
Leukocytosis
Margination
Diapedesis
Chemotaxis
What happens during leukocytosis?
release of neutrophils from bone marrow in response to leukocytosis-inducing factors from injured cells
What happens during margination?
neutrophils cling to the walls of capillaries in the inflamed area
What happens during diapedesis?
neutrophils squeeze through capillary walls and begin phagocytosis
What happens during chemotaxis?
inflammatory chemicals attract neutrophils to the injury site
What do mast cells bind and ingest?
wide range of bacteria
What are eosinophils weakly phagocytic towards?
parasitic worms
What cell types are phagocytic?
4
Neutrophils
Eosinophils
Mast cells
Monocytes
What chemicals inside the phagocyte help with digestion of pathogens?
3
Acid hydrolase enzymes
Cell-killing free radicals
Oxidizing chemicals
Describe the shape of NK cells
Large granular lymphocytes
What do NK cells target?
2
Cells that lack the “self” cell surface receptors
- cancer cells
- virus-infected cells
How do they kill the target cells?
inducing apoptosis by secreting perforins
How do they enhance the imflammatory response?
secreting potent chemicals that enhance it
What are the functions of inflammation?
3
- Prevents the spread of damaging agents
- Disposes of cell debris and pathogens
- Sets the stage for repair
5 cardinal signs of the inflammatory response?
- Redness
- Heat
- Swelling
- Pain
- (And sometimes 5. Impairment of function)
What are TLR’s?
resceptors on macrophages and epithelial cells. They recognize microbes/pathogens and signal an immune response
What do TLR’s trigger the release of?
cytokines
What do cytokines promote?
inflammation
Name the different types of inflammatory mediators
6
Histamines (from mast cells) Blood Protiens Kinins Prostaglandins Leukotrines Complement
What things release inflammatory mediators?
5
- Injured tissue
- phagocytes
- lymphocytes
- basophils
- mast cells
How do inflammatory chemicals affect blood flow to the injured area?
2
- Dilation of arterioles (hyperemia-excess blood in vessels)
- Increases permeability of local capillaries causing edema
What does exudate contain?
3
proteins
clotting factors
antibodies
What are the funciton of the surge of exudate?
2
- Moves foreign material into lymphatic vessels
2. Delivers clotting proteins to form a scaffold for repair and to isolate the area
What does the release of leukocytosis inducing factors result in?
phagocytosis of the pathogen and clean up of cell debris
What does the release of chemical mediators such as histamine, complement,
kinins, prostaglandins, etc. result in?
3
- vasodilation of arterioles
- Increased capillary permeability
- Attraction of neutrophils, monocytes and lymphocytes through chemotaxis
What is the funciton of inteferons and complements?
3
- Attack microorganisms directly
- Hinder microorganisms’ ability to reproduce
- reduce inflammation
How are INFs secreted?
by virus infected cells (to signal other cells to produce antiviral proteins that block viral reproduction
What kind of INFs do lymphocytes produce?
gamma (γ), or immune interferon
What kind of INFs do most other WBCs produce?
alpha (α) interferon
What kind of INF do fibroblasts produce?
beta (β) interferon
What other cells do inferons activate?
macrophages and mobilize NKs
What have we genetically engineered INFs for recently?
3
Hep
Genital warts
MS
What are complements secreted by? 2
hepatocytes and monocytes
What complements are commonly involved in the inflammatory response?
C1-C9
How do complements kill bacteria and other pathogens?
cell lysis
Describe the classical pathway of complement activation
2
- Antibodies bind to invading organisms
2. C1 binds to the antigen-antibody complexes (complement fixation)
Describe the alternative pathway for complement activation
Triggered when activated C3, B, D, and P interact on the surface of microorganisms
(no antibody)
What are the funciton of the activated compliment?
3
- Enhances inflammation
- Promotes phagocytosis
- Causes cell lysis
What does the C3b initiate in the complement pathway?
2
- formaiton of a membrane attack complex = cell lysis by causing massive influx of water = pop!
- can also causes opsonization
C3a causes?
inflammation
What causes the fever to start?
Leukocytes and macrophages exposed to foreign substances secrete pyrogens
How come our body cells can tolerate the heat of a fever but other cells cant?
Pyrogens reset the body’s thermostat upward
Benefits of a moderate fever?
2
- Causes the liver and spleen to sequester iron and zinc (needed by microorganisms)
- Increases metabolic rate, which speeds up repair
What are the two systems of adaptive defenses?
2
- Humoral (antibody-mediated) immunity (B cells)
2. Cellular (cell-mediated) immunity (T cells)
What are two important funcitons of antigens?
Immunogenicity and reactivity
What is immunogenicity?
ability to stimulate proliferation of specific lymphocytes and antibodies
What is reactivity referring to?
ability to react with products of activated lymphocytes and antibodies released
Examples of complete antigens?
4
foreign protein, polysaccharides, lipids, and nucleic acids
What are haptens?
Incomplete anitgens
How do haptens function?
2
- attach to body proteins to become immunogenic
2. stimulate the immune system to mount a harmful attack on its own body
Examples of haptens? 4
poison ivy, animal dander, detergents, and cosmetics
