Test 4 Study Guide Part 5 Flashcards
Why is blood usually sterile after a few passes through the liver, spleen or lymph nodes?
They have fixed phagocytic cells which lie within them
Usual role of macrophages:
Normally separate from immune system.
Clean cellular debris such as remnants of apoptotic cells
After activation of macrophages by PAMPs or some other signal, what do they do?
Secrete pro-inflammatory cytokines, some of which chemotaxis -> neutrophils enter first -> then monocytes (can be converted to macrophages)
How long does it take for neutrophils/monocytes to perform extravasation or diapedesis with an intact basement membrane?
up to 30 minutes.
Process of phagocytosis:
Endocytosis into -> vacuole (phagosome) -> lysozyme merges with vacuole -> Digested -> waste undigestible material is excreted
If a lysozyme releases it contents too early what happens?
It releases digestive enzymes.
These are proinflammatory.
phosphatidylserine and the immune response:
Phosphatidyl serine is normally on the inside of cells.
It is flipped to the outside in cells undergoing apoptosis.
it signals “eat me” to macrophages
It also acts to suppress the immune system
Why does phosphatidylserine suppress the immune system?
To limit collateral damage when macrophages are eating phagocytic cells
Endogenous Pyrogen:
- Define:
- By what process is it made?
- What else is it called?
- Define:
Substance the body makes which signals to produce fever - By what process is it made?
Macrophage or monocyte ingests bacterium with endotoxin (lipopolysaccharide) -> endogenous pyrogen - What else is it called?
Interleukin 1
Exogenous pyrogen:
Endotoxin
So endotoxin signals for our immune cells to make fever
Process of fever generation:
Macrophage encounters endotoxin -> produces interleukin-1 -> travels to hypothalamus -> sets thermostat higher
How does the hypothalamus increase body temp in response to pyrogen?
Causes shivering
Causes vasoconstriction via sympathetic innervation of skin, reducing heat diffusion
What happens to iron levels during fever?
Why?
They fall.
Bacteria need iron.
Interferon:
Produced by infected cells.
Signal for other cells to produce antiviral proteins
Gamma interferon is produce by what?
Helps to treat what?
Natural killer cells.
Infection and Cancer
What size are antigens normally?
Why?
10000 daltons (fairly large) Must be large enough to be unique
Ability to function as an antigen depends on:
Size
Complexity of structure
Antigenic Determinants:
- Other name:
- Define:
- Other name:
Epitope - Define:
Anything which can act as antibody (flagellum, outer receptors, lipopolysaccharides, etc.)
Hapten:
- Define:
- Drug induced thrombocytopenia purpura:
- Define:
A molecule with potential to be an antigen, but it is too small - Drug induced thrombocytopenia purpura:
Thrombocytes bind to hapten, making a functional antigen, the immune system responds against thrombocyte antigen complex
Immunoassays:
tiny polystyrene beads are coated with antibodies to a specific antigen.
These beads will agglutinate into visible balls if the antigen is present, this is an immunoassay
Lymphocytes arise:
- Other “seeded locations”:
- What happens at a seeded location:
Myeloid tissue of the bone marrow by stem cells
- Other “seeded locations”:
spleen, thymus, lymph nodes
- What happens at a seeded location:
Mitotic division and proliferation of immune cells
What does the T in T cells stand for?
Thymus-dependent
T-cell differentiation:
- How predominant are they?
Stem cells divide -> Lymphocytes which seed thymus become T lymphocytes -> Mature cells (matured in thymus)
~75% of lymphocytes are T lymphocytes
What does the B stand for in B cells?
What do we call it in people?
Bursa dependent
Bursa equivalent
Where do B cells mature/are processed?
In the bone marrow (bursa equivalent)
Primary lymphoid organs:
- List them:
- Why are they called primary lymphoid organs?
Bone marrow and thymus
This is where lymphocytes are released from
Acquired immunity:
- Other name:
- Two branches:
- Other name: specific immunity - Two branches: Cell mediated immunity (T-cell) humoral immunity (B-cell)
Humoral immunity:
- Is also called:
- Is also called:
Antibody-mediated immunity
Antibody structure:
Light chain, and heavy chain
cell-mediated immunity protects against:
Intracellular bacteria, intracellular viruses, fungi, protozoans, helminths (worms), transplanted tissue, and cancer cells
Humoral immunity protects against:
extracellular bacteria, extracellular viruses, bacterial toxins other protein toxins
Thymus gland:
- Location:
- Effect of age on thymus:
- Seeded by what, to produce what?
- Location: Chest Cavity (Bottom of the thyroid into the thoracic cavity) - Effect of age on thymus: Degenerates over the time - Seeded by what, to produce what? Seeded by lymphocytes from the fetal liver, spleen, and bone marrow seed the thymus T-cells
Repopulation of T-lymphocytes is slower in adulthood.
Why?
What repopulates them in adulthood?
Thymus degenerates into fatty organ with less activity
Secondary lymphoid tissues
Secondary lymphoid organs:
- List:
- Migration of lymphocytes:
- List: Peyer's patches tonsils spleen lymph nodes lymphatic vessels - Migration of lymphocytes: Constantly migrate between lymphoid tissues in blood and lymph, searching...
What is the name of cells which identify and present antigens?
Antigen presenting cells (APCs):
Antigen presenting cells:
- List:
Dendritic cells (predominately)
Macrophages
B-cells (to some degree)
Four cardinal signs of inflammatory reaction?
Rubor (Red)
Calor (Hot)
Dolor (Hurts)
Tumor (Swollen)
How does the inflammation response begin?
Stimulation of toll like receptor (by PAMPS) on macrophages and mast cells -> Release of cytokines and chemokines -> attract neutrophils, promote phagocytosis and compliment activation
What happens when the complement system is activated?
Chemotactic attractant for macrophages
Triggers release of proinflamatory chemicals (histamine being one), which promote blood vessel permeability
Mast Cells:
- Localized to:
- Two major molecules produced/stored within them?
- Localized to:
Skin, bronchioles, and intestinal mucosa (sites of entry) - Two major molecules produced/stored within them?
Heparin
Histamine
Histamine:
- Receptors;
- Effect mediated:
- Receptors:
H1 histamine receptor - Effect mediated:
Bronchiolar constriction
Vasodilation (relax smooth muscles in veins)
Causes endothelial cells of capillaries to contract away from capillaries, making gaps between them (aids permeability)
What causes the localized edema associated with inflammation?
Release of histamine, seratonin, and other by mast cells (and other cells).
Contraction of endothelium of capillaries away from capillary
Increased permeability
Degranulation of mast cells:
Histamine and heparine granules are exocytosed
Granules of protease enzymes are exocytosed more slowly
After a time delay, progtaglandins, leukotrienes and other proinflamtory cytokines are released (including tumor necrosis factor)
leukotrienes:
- Define:
- Causes:
- Define: released by mast cells and leukocytes. - Causes: Increased capillary permeability Constriction of brachioles attraction of leukocytes
Tumor necrosis factor:
Produced by mast cells and macrophages
Attracts neutrophils
Entry of leukocytes into a region of inflammation:
Extravassion (diapedesis)
Leukocytes bind to cell capillary endothelium through adhesion molecules
Leukocytes roll towards chemokines (Complement proteins, bacterial products)
Chemotaxis:
- Define:
- How do leukocytes do it?
- Define:
movement towards a chemical - How do leukocytes do it?
Roll on cells surface
Order at which leukocytes arrive to inflamation
Neutrophils
Monocytes -> Macrophages
T - cells
Neutrophils:
- Do what upon arrival:
- Do what upon arrival:
Recruit additional monocytes, lymphocytes and other immune cells
Phagocytose microbes
release enzymes, and antimicrobial peptides
Neutrophil Extracellular Traps
Neutrophil Extracellular Traps:
Extracellular fibers trap invading pathogens, immobilizing them, facilitating their phagocytosis, and possibly killing them directly by antimicrobial enzymes
The enzymes secreted by neutrophils have what effect?
They are proteases, the liquify the surrounding tissue
What is in pus?
How does pus help?
How does pus affect antimicrobials?
- What is in pus?
Protein rich fluid, filled with dead neutrophils, and macrophages - How does pus help?
Builds up pressure that closes lymphatic and blood capillaries, stopping bacteria from spreading - How does pus affect antimicrobials?
It is difficult for them to penetrate pus, which is why we drain it
