Lymphoid Organs

Question 0

Secondary Lymphoid Organs

Answer 0

MALT
Spleen
Lymph Nodes

Question 1

Primary Lymphoid Organs

Answer 1

BM and Thymus

Question 2

Adaptive Immunity

Answer 2

Occurs after 1-6 days; mediated by B-cells and T-cells activated by macrophage products

Question 3

N-terminal regions

Answer 3

“Variable regions”

Composed of variable heavy an light chains

Question 4

IgE

Answer 4

Secreted; binds to mast cells

*Parasitic infxns and allergic rxn

Question 5

IgM

Answer 5

Largest Ab; secreted as a pentamer and found in membranes

*Contains B-cell Ag receptors

Question 6

IgD

Answer 6

Membrane Ig; contains B-cell Ag receptor

Question 7

IgG

Answer 7

Primary Ig found in serum; responsible for adaptive “memory” and neonatal immunity

*Also important in phagocytosis (marks Ags)

Question 8

IgA

Answer 8

Secreted dimer found in mucous membranes

Question 9

T-Cell Antigen Receptor

Answer 9

Have a single Ag binding site w/ both alpha and beta chains

*Recognizes small peptides on the surface of APCs

Question 10

Clonal Expansion

Answer 10

B-cells recognize an Ag, produce clones of plasma cells that secrete Ab to destroy foreign substance

Question 11

B-cells

Answer 11

Use membrane bound antibodies to recognize a variety of epitopes; can turn into plasma cells

Question 12

T-cell Selection

Answer 12

Positive: Cells w/ useful Ag receptors

Negative: Cells that react too strongly and can’t differentiate self

*This process peaks from birth-puberty

Question 13

Blood-thymus barrier

Answer 13

Prevents exposure of immature T-cells to foreign Ags

-Formed by endothelial cells w/ tight jnxns and thick basal lamina

Question 14

MALT

Answer 14

Collections of lymphoid cells that are adjacent to mucous and exposed to the external environment; has high concentrations of IgA

*Found in the GI, respiratory, and reproductive tracts

Question 15

High Endothelial Venules

Answer 15

Location @ which lymphocytes enter lymph nodes from blood vessels

*Tall, cuboidal epithelia

Question 16

Spleen

Answer 16

Removes aged/damaged RBCs an activates B-lymphocytes

Question 17

Peyer’s Patches

Answer 17

Lymph nodes found in the lamina propria and sub-mucosa of the ileum

Question 18

Germinal Centers

Answer 18

Location where lymphocyte proliferation occurs

*Spleen may not have them

Question 19

Location of T-cells in Lymphatic Nodules

Answer 19

Paracortex

Question 20

Hassall’s Corpuscles

Answer 20

Key histological feature of the thymus; found in the medulla of the thymus

Question 21

Red pulp

Answer 21

Dense, reticular fibers of the spleen that contain RBCs, WBCs, and other cells that remove aged RBCs

Question 22

Splenic cords

Answer 22

Aggregations of lymph tissue found in the red pulp

Question 23

Venous sinuses

Answer 23

Dilated vessels w/ cuboidal epithelial cells found in the red pulp

Question 24

IgA secretion

Answer 24

IgA binds to polyIg receptors on mucosal cells, is internalized and transported across the cell where it is cleaved and released into the lumen of the organ

Question 25

White Pulp

Answer 25

Aggregations of lymph nodes found in the trabeculae of the spleen