Week 1 Pathogens and Innate Immunity Flashcards
Overall function of the immune system
Destroy ____
Detect and kill ____
Remove ____
Overall function of the immune system
Destroys pathogens
Detects and kills abnormal cells
Remove cell debris (fragmented remains of dead or damaged cells) from body
Main types of pathogens
Pathogens can be ____ or ____.
____,
____,
____ (),
____ (),
____ ().
Structure: ____ + ____ (+ ____)
Mechanism:
____ → ____ →____
→ ____ → ____
Main types of pathogens
Pathogens can be Intracellular or extracellular
Parasitic worms
Fungi
Protozoa (unicellular eukaryotes)
Pathogenic bacteria (unicellular prokaryotes)
Viruses (not considered alive)
Components of the immune system
Primary lymphoid tissue:____(what)
____: ____ (function)
____: ____ (function)
Secondary lymphoid tissue: ____ (what)
Encapsulated lymphoid tissues
____: ____ (function)____(immune cell present)
____: ____ (function)____(immune cell present)
Diffuse lymphoid tissue
____()(where to find)
____
____
Lymphatic vessels
____ (function)
____ (function)
____ (function)
Components of the immune system
Primary lymphoid tissue: Development and maturation of immune cells
Thymus: Produces T lymphocytes.
Bone Marrow: Produces most immune cells.
Secondary lymphoid tissue: Where the cells of the immune system encounter antigen and generate immune response.
Encapsulated lymphoid tissues
Lymph nodes monitor lymph for pathogens and generate immune response before returning it to the bloodstream.
Spleen monitors blood for pathogens and generates an immune response.
Both contain mature immune cells that interact with pathogens and generate an immune response.
Diffuse lymphoid tissue:
Mucosa-associated lymphoid tissue (MALT)
(found in GI track, lung)
skin
tonsils
Lymphatic vessels
Function
1) Return excess interstitial fluid to the blood (~3 L/day)
2) Transport lymph (pathogens/dendritic cells) to lymph nodes
3) Transport fat from digestive system to the blood
Immune cells found in blood, lymph and tissues
Immune cells found in circulation: ____,(____, ____, ____), ____, ____, ____, ____.
Immune cells found in tissue:
(____, ____, ____, ____)
____
____, ____
Lymphocyte
(Circulation/Tissue)
(Type of Immune response)
Monocytes
(Circulation/Tissue)
(Type of Immune response)
(Mechanism of Immune response)
Neutrophils
(Circulation/Tissue)
(Type of Immune response)
(Mechanism of Immune response)
Eosinophils
(Circulation/Tissue (what tissue specifically))
(Type of Immune response)
(Immune response to?)x2
Basophils and mast cells
(Circulation/Tissue)
(Type of Immune response)
(Immune response to?)
(Mechanism of Immune response)
Dendritic cells
(Mechanism of Immune response)
APC:
Lymphocyte
Migrate into tissues and mature into T and B cells (adaptive immunity), NK cells (innate immunity)
Monocytes
Migrate into tissues and mature into macrophages
Antigen presenting Cell (APC)
Phagocytic
Neutrophils
Circulate in the blood and can migrate into tissues
Innate immune response
Phagocytic and Granulocytic and extracellular traps (nets)
Eosinophils (found in GI tract, lungs, urinary and genital epithelia)
Circulate in blood
Defend against parasites, Allergic reactions
Basophils and mast cells
Basophils circulate in blood, mast cells in tissue.
innate immune response
inflammation
Granulocytic
Dendritic cells
Present antigens
Phagocytic
Basic steps in the immune system
1)____
2)____
3)____
4)____
Basic steps in the immune system
1) Detect and identify the pathogen
2) Communicate with other immune cells
3) Recruit and coordinate response among all participants
4) Destroy or suppress the pathogen
Type of immune response
____ Immunity: ____, ____(characteristics)
____ Immunity: ____, ____ (characteristics)
Type of immune response
Innate Immunity: Rapid, non-specific
Adaptive Immunity (Acquired Immunity): Slower, specific
Key elements of the innate immune system
1)
2)
3)
4)
5)
6)
1) Physical barriers
2) Phagocytes
3) Natural killer (NK) cells
4) Antimicrobial proteins
5) Inflammation
6) Fever
Physical barriers
Epithelium
____, ____
Glandular Secretions
____, ____, ____
____ (mechanism)
Stomach Acidity
____
____ (mechanism)
Mechanical Removal
____ ____(mechanism)
____ ____ ____ ____
Epithelium
Skin and mucous membranes
Glandular Secretions
Mucus, antibodies, and enzymes trap and disable pathogens
Stomach Acidity
Low pH in the stomach destroys pathogens that are swallowed
Mechanical Removal
Mucociliary escalator clears mucus from the respiratory tract
Tears, coughing, sneezing, and GI motility
Phagocytes
____ (function)
Mechanism
____
→ ____: ____
→ ____: ____
____(how? (2 possibilities))
→ ____: ____
____(how?)
→ ____: ____
Macrophages, neutrophils, and dendritic cells engulf and kill pathogens presenting chemotaxins or opsonins.
Mechanism
Cell adhesion molecules on endothelial cells transports phagocytes
→ Diapedesis (extravasation)
The leakage of blood, lymph from a blood vessel or tube into the tissue around it
→ Chemotaxis
Pathogens pattern recognition receptors on phagocytes bind to chemotaxins
= Pathogen-associated molecular patterns(PAMPs)
e.g. bacterial toxins + cell wall components
Damage-associated molecular patterns(DAMPs)
e.g. DNA
Cytokines
/
Phagocytes binds to opsonins
opsonization: coating pathogens with opsonins (e.g., antibodies)
→ Phagocytosis
Phagocytes engulf, ingest and breakdown pathogens.
= Lysosome contains enzymes and oxidants + Phagosome contains ingested pathogen
→ Antigen Presentation
macrophages and dendritic cells display antigen fragments on their surface using class II MHC molecule
Antigens: Unique molecules on a pathogen that the immune system identifies as foreign.
Natural Killer (NK) Cells
____ (function)
Background: ____
Mechanism: ____
Natural Killer (NK) Cells
NK cells kill cells lacking MHC class I (typically infected or cancerous cells).
Antimicrobial Proteins (secreted from cell in an ____ state)
Interferons
α and β ____ (function_
γ ____ (function)
Complement proteins (___ plasma proteins)
____ (function 1)
____ (function 2)
____ (function 3)
Mechanism of complement proteins
Classical Pathway: ____
Lectin Pathway: ____
Alternative Pathway: ____
Antimicrobial Proteins (secreted from cell in an inactive state)
Interferons
α and β prevent viral replication;
γ activates macrophages and other cytotoxic T cells
Complement proteins: a group of 25 plasma proteins
Form membrane attack complex to destroy pathogen membranes
Cause inflammation by activating mast cell
Promote opsonization to attract phagocytes for phagocytosis.
Mechanism of complement proteins
Classical Pathway: Activated by antigen-antibody complexes.
Lectin Pathway: Involves mannose-binding lectins that bind to pathogen surface polysaccharides.
Alternative Pathway: Activated by microbial surfaces with no inhibitors.
(Acute) Inflammation
Symptoms
____: ____ (function)
____: ____ (function)
____,____: ____ (function)
____ (overall function)
Mechanisms
____: ____
↓
____: ____
1)
↓
____:____
↓
____:____
↓
____
2)
↓
____ (especially____)
↓
____
(Acute) Inflammation
Swelling, redness, heat, pain.
Swelling slows the spread of pathogens,
Redness (increased blood flows): mobilizes defenses
Heat, pain: inform us about the site of injury
Sets the stage for tissue repair.
Mechanisms
Tissue Damage
Chemical changes occur in the interstitial fluid due to tissue injury
↓
Activation of Mast Cells
Mast cells release histamine and heparin (chemotaxins)
1)
histamine
↓
Dilation of Blood Vessels
Increased blood flow and vessel permeability
(Area becomes red and swollen)
↓
Clotting factors, antibodies, complement proteins, and kinins move into the interstitial tissue to aid in the clotting process.
Kinin cascade leads to formation of vasodilator bradykinin and stimulates pain receptors
(Area becomes warm and painful)
↓
Clot formation
2)
chemotaxins
↓
Chemotaxis of Phagocytes (especially neutrophils)
↓
Debris removal through phagocytosis by neutrophils and macrophages.
Stimulation of tissue repair
Fever
Body Temperature above ____.
____ (Function 1)
____ (Function 2)
Mechanism
____ (e.g. ____, ____ by ____)
Body temperature above 37.2°C
Speeds up metabolic activity of host cells
Inhibits some pathogens who are susceptible to death at high temperature
Pyrogens released change the thermoregulatory set point in the hypothalamus
