Test 4 Study Guide Part 5

Question 1

Why is blood usually sterile after a few passes through the liver, spleen or lymph nodes?

Answer 1

They have fixed phagocytic cells which lie within them

Question 2

Usual role of macrophages:

Answer 2

Normally separate from immune system.

Clean cellular debris such as remnants of apoptotic cells

Question 3

After activation of macrophages by PAMPs or some other signal, what do they do?

Answer 3

Secrete pro-inflammatory cytokines, some of which chemotaxis -> neutrophils enter first -> then monocytes (can be converted to macrophages)

Question 4

How long does it take for neutrophils/monocytes to perform extravasation or diapedesis with an intact basement membrane?

Answer 4

up to 30 minutes.

Question 5

Process of phagocytosis:

Answer 5

Endocytosis into -> vacuole (phagosome) -> lysozyme merges with vacuole -> Digested -> waste undigestible material is excreted

Question 6

If a lysozyme releases it contents too early what happens?

Answer 6

It releases digestive enzymes.

These are proinflammatory.

Question 7

phosphatidylserine and the immune response:

Answer 7

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

Question 8

Why does phosphatidylserine suppress the immune system?

Answer 8

To limit collateral damage when macrophages are eating phagocytic cells

Question 9

Endogenous Pyrogen:

• Define:
• By what process is it made?
• What else is it called?

Answer 9

• 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

Question 10

Exogenous pyrogen:

Answer 10

Endotoxin

So endotoxin signals for our immune cells to make fever

Question 11

Process of fever generation:

Answer 11

Macrophage encounters endotoxin -> produces interleukin-1 -> travels to hypothalamus -> sets thermostat higher

Question 12

How does the hypothalamus increase body temp in response to pyrogen?

Answer 12

Causes shivering

Causes vasoconstriction via sympathetic innervation of skin, reducing heat diffusion

Question 13

What happens to iron levels during fever?

Why?

Answer 13

They fall.

Bacteria need iron.

Question 14

Interferon:

Answer 14

Produced by infected cells.

Signal for other cells to produce antiviral proteins

Question 15

Gamma interferon is produce by what?

Helps to treat what?

Answer 15

Natural killer cells.

Infection and Cancer

Question 16

What size are antigens normally?

Why?

Answer 16

10000 daltons (fairly large)
Must be large enough to be unique

Question 17

Ability to function as an antigen depends on:

Answer 17

Size

Complexity of structure

Question 18

Antigenic Determinants:

• Other name:
• Define:

Answer 18

• Other name:
  Epitope
• Define:
  Anything which can act as antibody (flagellum, outer receptors, lipopolysaccharides, etc.)

Question 19

Hapten:

• Define:
• Drug induced thrombocytopenia purpura:

Answer 19

• 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

Question 20

Immunoassays:

Answer 20

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

Question 21

Lymphocytes arise:

• Other “seeded locations”:
• What happens at a seeded location:

Answer 21

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

Question 22

What does the T in T cells stand for?

Answer 22

Thymus-dependent

Question 23

T-cell differentiation:

- How predominant are they?

Answer 23

Stem cells divide -> Lymphocytes which seed thymus become T lymphocytes -> Mature cells (matured in thymus)
~75% of lymphocytes are T lymphocytes

Question 24

What does the B stand for in B cells?

What do we call it in people?

Answer 24

Bursa dependent

Bursa equivalent

Question 25

Where do B cells mature/are processed?

Answer 25

In the bone marrow (bursa equivalent)

Question 26

Primary lymphoid organs: - List them: - Why are they called primary lymphoid organs?

Answer 26

Bone marrow and thymus | This is where lymphocytes are released from

Question 27

Acquired immunity: - Other name: - Two branches:

Answer 27

``` - Other name: specific immunity - Two branches: Cell mediated immunity (T-cell) humoral immunity (B-cell) ```

Question 28

Humoral immunity: | - Is also called:

Answer 28

- Is also called: | Antibody-mediated immunity

Question 29

Antibody structure:

Answer 29

Light chain, and heavy chain

Question 30

cell-mediated immunity protects against:

Answer 30

Intracellular bacteria, intracellular viruses, fungi, protozoans, helminths (worms), transplanted tissue, and cancer cells

Question 31

Humoral immunity protects against:

Answer 31

extracellular bacteria, extracellular viruses, bacterial toxins other protein toxins

Question 32

Thymus gland: - Location: - Effect of age on thymus: - Seeded by what, to produce what?

Answer 32

``` - 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 ```

Question 33

Repopulation of T-lymphocytes is slower in adulthood. Why? What repopulates them in adulthood?

Answer 33

Thymus degenerates into fatty organ with less activity | Secondary lymphoid tissues

Question 34

Secondary lymphoid organs: - List: - Migration of lymphocytes:

Answer 34

``` - List: Peyer's patches tonsils spleen lymph nodes lymphatic vessels - Migration of lymphocytes: Constantly migrate between lymphoid tissues in blood and lymph, searching... ```

Question 35

What is the name of cells which identify and present antigens?

Answer 35

Antigen presenting cells (APCs):

Question 36

Antigen presenting cells: | - List:

Answer 36

Dendritic cells (predominately) Macrophages B-cells (to some degree)

Question 37

Four cardinal signs of inflammatory reaction?

Answer 37

Rubor (Red) Calor (Hot) Dolor (Hurts) Tumor (Swollen)

Question 38

How does the inflammation response begin?

Answer 38

Stimulation of toll like receptor (by PAMPS) on macrophages and mast cells -> Release of cytokines and chemokines -> attract neutrophils, promote phagocytosis and compliment activation

Question 39

What happens when the complement system is activated?

Answer 39

Chemotactic attractant for macrophages | Triggers release of proinflamatory chemicals (histamine being one), which promote blood vessel permeability

Question 40

Mast Cells: - Localized to: - Two major molecules produced/stored within them?

Answer 40

- Localized to: Skin, bronchioles, and intestinal mucosa (sites of entry) - Two major molecules produced/stored within them? Heparin Histamine

Question 41

Histamine: - Receptors; - Effect mediated:

Answer 41

- 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)

Question 42

What causes the localized edema associated with inflammation?

Answer 42

Release of histamine, seratonin, and other by mast cells (and other cells). Contraction of endothelium of capillaries away from capillary Increased permeability

Question 43

Degranulation of mast cells:

Answer 43

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)

Question 44

leukotrienes: - Define: - Causes:

Answer 44

``` - Define: released by mast cells and leukocytes. - Causes: Increased capillary permeability Constriction of brachioles attraction of leukocytes ```

Question 45

Tumor necrosis factor:

Answer 45

Produced by mast cells and macrophages | Attracts neutrophils

Question 46

Entry of leukocytes into a region of inflammation:

Answer 46

Extravassion (diapedesis) Leukocytes bind to cell capillary endothelium through adhesion molecules Leukocytes roll towards chemokines (Complement proteins, bacterial products)

Question 47

Chemotaxis: - Define: - How do leukocytes do it?

Answer 47

- Define: movement towards a chemical - How do leukocytes do it? Roll on cells surface

Question 48

Order at which leukocytes arrive to inflamation

Answer 48

Neutrophils Monocytes -> Macrophages T - cells

Question 49

Neutrophils: | - Do what upon arrival:

Answer 49

- Do what upon arrival: Recruit additional monocytes, lymphocytes and other immune cells Phagocytose microbes release enzymes, and antimicrobial peptides Neutrophil Extracellular Traps

Question 50

Neutrophil Extracellular Traps:

Answer 50

Extracellular fibers trap invading pathogens, immobilizing them, facilitating their phagocytosis, and possibly killing them directly by antimicrobial enzymes

Question 51

The enzymes secreted by neutrophils have what effect?

Answer 51

They are proteases, the liquify the surrounding tissue

Question 52

What is in pus? How does pus help? How does pus affect antimicrobials?

Answer 52

- 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