Immune System

Question 1

What are the 3 cells of the immune system

Answer 1

lymphocytes, antigen presenting cells (APCs) and reticular cells

Question 2

What is the function of reticular cells?

Answer 2

to create a connective tissue scaffolding to house lymphocytes.
synthesize collagen to produce reticular fibers.

Question 3

where are APCs found?

Answer 3

in lymphoid organs and other tissues/areas that are regularly exposed to antigens

Question 4

What are APCs derived from?

Answer 4

Bone marrow

Question 5

What are some types of antigen presenting cells?

Answer 5

Dendritic cells, langerhans cells, macrophages, B-cells

Question 6

What is the purpose of a primary lymphoid tissue?

Answer 6

a site of maturation for lymphocytes

Question 7

What are the primary lymphoid tissues?

Answer 7

thymus, bursa of fabricus, ilocecal peyer’s patches, bone marrow

Question 8

What is the purpose of a secondary lymphoid tissue?

Answer 8

site of function for lymphocytes

Question 9

What are the secondary lymphoid tissues?

Answer 9

tonsils, spleen, lymph nodes, peyer’s patches

Question 10

What will you find in the cortex of the thymus?

Answer 10

T-cells at various stages of maturation

Question 11

What will you find in the medulla of the thymus?

Answer 11

fully mature T-cells

Question 12

How do you differentiate the thymus cortex from the medulla on a slide?

Answer 12

the medulla is lighter staining and has fewer lymphocytes

Question 13

Explain the blood flow to the cortex of the thymus

Answer 13

continuous capillaries penetrate the cortex - prevents immature lymphocytes from entering circulation

Question 14

Explain the blood flow to the thymus medulla

Answer 14

the epithelial reticular cells coving blood vessels is incomplete to the venules at the cortico-medullary juntion are permeable to macromolecules and cells. (sinusoidal capillaries) Allows mature lymphocytes to enter circulation.

Question 15

common features of secondary lymphoid tissues:

Answer 15

presence of nodules/follicles
sites for immunologic surveillance
localizes the immune responses

Question 16

what do nodules/follicles primarily consist of?

Answer 16

B-cells

Question 17

Function of a lymph nodule

Answer 17

collect antigen moving through lymph in the body and filters it before returning it to the bloodstream. Trap antigens and present thm to B or T-cells

Question 18

function of the spleen

Answer 18

traps antigen circulating in the blood

Question 19

What is MALT

Answer 19

mucosa associated lymphatic tissue (i.e. tonsils)

Question 20

function of MALTs

Answer 20

traps antigens attempting to enter the body through the mucosa and skin

Question 21

How can you tell if a lymph nodule is active?

Answer 21

Presence of germinal center (within the mantle or corona)
If within a lymph node, it will enlarge

Question 22

In what species will you find a hemal node?

Answer 22

ruminants

Question 23

functions of lymph nodes

Answer 23

mechanical and phagocytic filtration of lymph
proliferation of lymphocytes
immune response: cellular or humoral response

Question 24

Explain the flow of lymph through a lymph node

Answer 24

enters through afferent vessels which empty into the subscapular sinus. Lymph flows into the cortical sinuses, then flows into the medullary sinuses. Lymph leaves via efferent vessels at the hilus

Question 25

Lymph nodes are comprised of **?**

Answer 25

lymph nodules

Question 26

What cells will you find in the mantle (or corona) of the lymph nodule?

Answer 26

primarily B-cells

Question 27

What cells will you find in the paracortical zone of the lymph nodule

Answer 27

primarily T-cells

Question 28

What is the function of the arrangement of the reticular cells in the medullary sinuses?

Answer 28

slows lymph flow, facilitating antigen-cell interactions and phagocytosis

Question 29

How does lymph flow differ in a tonsil or MALT from flow through a lymph node?

Answer 29

MALT have no afferent vessels. only efferent

Question 30

What is the largest lymphatic organ in the body?

Answer 30

the spleen

Question 31

What are the two pulp types found in the spleen

Answer 31

red pulp and white pulp

Question 32

What does the red pulp of the spleen consist of

Answer 32

primarily RBCs (vascular system)

Question 33

what does the white pulp of the spleen consist of?

Answer 33

immune system, WBCs in the PALs - T-cells in the lymphoid follicles - B-cells in the marginal zone - plasma cells and macrophages

Question 34

What color stain does the red pulp pick up? why?

Answer 34

pink! acidophilic due to the presence of RBCs

Question 35

How do you identify white pulp?

Answer 35

White pulp (parenchyma) has a central artery surrounded by T-cells (very basophilic) and splenic nodules (active B-cells)

Question 36

Function of the white pulp in the spleen?

Answer 36

defense - humoral and cellular immunity

Question 37

function of red pulp of the spleen

Answer 37

filtration and storage of blood

Question 38

What are hemal lymph nodes?

Answer 38

like small spleens (kinda between a lymph node and a spleen) in ruminants only

Question 39

Explain the general flow of lymph

Answer 39

1. APC with antigen migrate to lymph node (enter node via affernt lymph) 2. lymphocytes interact with APC and proliferate 3. Lymphocytes exit node with efferent lymph 4. Lymph enters blood at anterior vena cava/subclavian vein 5. Lymphocytes exit blood and enter inflammed tissue

Question 40

Antigen vs antibody

Answer 40

Antigens allow your body to create a defense against future invaders. Antibodies circulate in your body once created to identify, attack, and destroy the same type of antigens if they enter the body again

Question 41

another name for antibody?

Answer 41

immunoglobin

Question 42

what type of cells produce Abs?

Answer 42

plasma cells