Immunology - Cells And Organs Of The Adaptive Is

Front 1

What are the primary (central) lymphoid organs?

Back 1

Thymus

Bone marrow

Bursa of fabricious (birds)

Front 2

Define "primary lymphoid organ."

Back 2

An organ that provides the appropriate microenviro for lymphocyte devo and maturation; where lymphocytes become immunocompetent.

Front 3

What are the secondary (peripheral) lymphoid organs?

Back 3

Lymph nodes

Spleen

Mucosa-associated lymphoid tiss (MALT)

Front 4

Define "secondary lymphoid organ."

Back 4

An organ that traps antigens and where mature lymphocytes can interact and mount an immune response.

Front 5

List 3 examples of MALT.

Back 5

GALT: gut-ALT in submucosa of GIT - Peyer's patches, pharyngeal and cecal tonsils

BALT: bronchial-ALT
Repro tract lymphoid nodules

Front 6

What major lymphoid organ do nude mice lack? Why? What is the significance of this?

Back 6

Thymus

Genetic mutation: mutated TF

No rejection of skin grafts - no differentiation bw "self" and "non-self/foreign".

**Recognition of self vs non-self depends on thymus.**

Front 7

What is the major site of hematopoeisis in mammals and birds?

Back 7

Bone marrow

Front 8

To which cell lineages does bone marrow give rise?

Back 8

Myeloid

Lymphoid

Erythroid

Megakaryocytic

Front 9

Bone marrow is the site of _______ maturation in birds.

Back 9

B-cell

Front 10

True or false?

All B-cells are fit to become active cells of the adaptive IS.

Back 10

False. B-cells w self-reactive Ab receptors are eliminated.

Front 11

Which spp have significant B-cell maturation in Peyer's patches?

Back 11

Cattle and sheep
(other mammals too, but to a lesser extent)

Front 12

Describe the 5 processes (eg granulopoiesis) that a hematopoietic stem cell in the bone marrow can undergo.

Back 12

1. Granulopoiesis --> neuts, eosinophils, basophils

2. Monoyctopoiesis --> monocytes, macs

3. Erythropoiesis --> RBCs

4. Thrombopoiesis --> megakaryocytes, platelets

5. Lymphopoiesis --> lymphocytes, plasma cells

(1. 2. 3. 4. myeloid lineage, 5. lymphoid lineage)

Front 13

Which animals have a bursa of Fabricious and where is it located on the body?

Back 13

Birds

Cloaca

Front 14

What does the bursa of Fabricious do?

Back 14

Destroys self-reactive B-cells (confers immunocompetence).

Front 15

What happens to the thymus as an animal ages?

Back 15

Larger in young animals; involutes w age.

Front 16

What part of the thymus selects for immunocompetent T-cells?

Back 16

The cortex

Front 17

What is the role of the medulla of the thymus?

Back 17

Secondary T-cell selection.

Front 18

What percentage of T-cells undergo apoptosis in the thymus? Why?

Back 18

90-95%

Thymus must destroy T-cells that react to self Ag.

Front 19

Within the thymus, ________ become _______, which learn to differentiate self/non-self.

Back 19

thymocytes

T lymphocytes

Front 20

Within the thymus, immature cells hang out in the _______, whereas mature cells hang out in the _______.

Back 20

cortex

medulla

Front 21

Which secondary lymphoid organ filters interstitial fluid?

Back 21

Lymph nodes

Front 22

Which secondary lymphoid organ filters blood?

Back 22

Spleen

Front 23

What are the 3 major functions of lymph nodes?

Back 23

1. Trap Ag

2. Provide meeting point for APCs and lymphocytes

3. Provide site for clonal expansion of lymphoid cells (acquired IS)

Front 24

What is the term for expansion of the lymph nodes after Ag exposure?

Back 24

Hyperplasia

Front 25

During lymph node hyperplasia, which cells expand and where are they located?

Back 25

B-cell follicles in cortex and T-cells in paracortex expand.

Front 26

What are the 3 histological layers of lymph nodes?

Back 26

Cortex

Paracortex

Medulla

Front 27

Which cells hang out in the cortex of lymph nodes?

Back 27

Naive B-cells form cortical follicles.

Germinal centre form w Ag stimulation.

Front 28

Which cells hang out in the medulla of lymph nodes?

Back 28

plasma cells and macs

Front 29

True or false?

Germinal centres that form in lymph node cortices in response to Ag stimulation are only visible on histological section.

Back 29

False. They are also visible grossly.

Front 30

The spleen filters blood and traps blood-bourne pathogens in response to ________ infections.

Back 30

Systemic

Front 31

What is the difference bw red and white pulp in the spleen?

Back 31

Red: macs and RBCs (old/senescent/defective RBCs destroyed)

White: lymphoid tiss

Front 32

What will be the gross appearance of the spleen from a patient w immune-mediated hemolytic anemia?

Back 32

Enlarged

Front 33

What are the 3 layers of the spleen?

Back 33

1. B-cell corona

2. Germinal centre

3. periarteriolar lymphoid sheaths (PALS) - mostly T cells

Front 34

Why do bacteria usu show up in MALT before showing up in blood?

Back 34

The mucous membs lining digestive, resp, and UG systems are maj sites of entry for many pathogens.

Front 35

Describe the texture and organization of MALT.

Back 35

Loose, barely-organized clusters of lymphoid tiss.

B-cells organized into follicles.

Germinal centres surrounded by a T-cell zone.

M-cells in epithelium.

Front 36

What do M-cells do?

Back 36

In MALT epithelium, endocytose and present Ag to lymphocytes in submucosa.

Front 37

Describe the path taken by cells when M-cells detects Ag.

Back 37

Ag!!! --> M-cells in epithlieum endycytose Ag and present to lymphocytes in submucosal Peyer's patches --> macs/DCs bring new Ag to mesenteric lymph node to interact w B and T cells --> primed B and T cells travel back via systemic circulation to site of Ag/danger signals to fight off infection (takes a few days).