Organs of the Immune System

Question 1

Describe the progression of organs or tissues involved in the production of lymphoid cells.

Answer 1

Yolk sac, Fetal omentum, Liver, Spleen, then Bone marrow

Question 2

A _________ lymphoid organ is associated with the proliferation and differentiation of lymphocytes.

Answer 2

Secondary

Question 3

A _________ lymphoid organ is associated with the production and maturation of lymphocytes.

Answer 3

Primary

Question 4

What organs would be considered primary lymphatic organs in rabbits, poultry, dogs, ruminants, and swine?

Answer 4

Cloacal bursa aka Bursa of Fabricius
Bone marrow
Thymus
Peyer’s Patches

Question 5

What organs would be considered secondary lymphatic organs in horses and cats?

Answer 5

Spleen
Lymph nodes
MALT
Peyer’s Patches

Question 6

Where does T lymphocyte maturation occur?

Answer 6

The thymus gland

Question 7

What occurs to the thymus gland as age increases?

Answer 7

It involutes, or decreases in size

Question 8

Where do B lymphocytes develop and mature?

Answer 8

Cloacal bursa aka Bursa of Fabricius, bone marrow, peyer’s patches (dogs, rabbits, ruminants, swine)

Question 9

Where are B and T lymphocytes produced?

Answer 9

The bone marrow

Question 10

T/F: Lymph nodes, the thymus gland, and the spleen have capsules.

Answer 10

True

Question 11

In the thymus gland, where would lymphocytes be located?

Answer 11

In the cortex

Question 12

In the thymus gland, where would a decreasingly small number of thymocytes be located?

Answer 12

In the medulla

Question 13

What tests do maturing T lymphocytes undergo in the thymus gland? Describe these tests.

Answer 13

Negative selection = must be able to recognize self from non-self and not bind strongly to these receptors

Positive selection = must be able to bind to MHC II/Ag complexes with a moderate affinity

Question 14

What occurs to T lymphocytes that fail to recognize “non-self” cells and bind to strongly to “self” cells?

Answer 14

They are eliminated via apoptosis

Question 15

If T cells were not negatively selected, what would result?

Answer 15

Autoimmunity as they would attack “self” cells

Question 16

If T cells were not positively selected, what would result?

Answer 16

An inability to combat infections as they are unable to recognize extracellular or intracellular antigens

Question 17

T/F: Depending on the binding affinity of a T cell being positively selected, if they have an increased binding ability to MHC II/Ag complexes they are selected to become CD4+ cells, while those T cells with lower binding affinities are programmed to become CD8+ cells.

Answer 17

False, T cells with a stronger affinity become CD8+ cells, as T cells with a lower affinity become CD4+ cells

Question 18

T/F: The bursa of fabricius does not involute over time.

Answer 18

False, it does similarly to the thymus gland

Question 19

The epithelium of the cloacal bursa makes folds that extend into _________ that have a medulla and _____, which contains lymphocytes, macrophages, and __________. This area is the site of both ________ and ________ selection of B cells.

Answer 19

Follicles
Cortex
Plasma cells
Negative
Positive

Question 20

Which of the following is not true of secondary lymphoid tissues?
A) Contain both dendritic cells and monocytes that will differentiate into resident macrophages
B) Surgical removal will impair lymphatic drainage but not immune capability
C) They develop late in fetal life and will enlarge in response to antigenic stimulation
D) Can be either encapsulated on non-encapsulated

Answer 20

A) Contain both dendritic cells and monocytes that will differentiate into resident macrophages

Question 21

Lymph nodes contain a region that comprises predominantly B lymphocytes called the ________, in structures called germinal centers.

Answer 21

Cortex

Question 22

Lymph nodes contain a region that comprises extensive amounts of T lymphocytes call the ___________, which are also associated with dendritic cells present here as well for antigen presentation.

Answer 22

Paracortex

Question 23

Afferent vessels will not contain which of the following?
A) Antibodies
B) Antigens
C) Dendritic cells
D) Macrophages

Answer 23

D) Macrophages

Question 24

Within the spleen what does the following area function to do?

Answer 24

Blood filtering, erythrocyte and PLT storage, and recycling iron

Question 25

Within the spleen what does the following area function to do?

Answer 25

Site of immune induction

Question 26

Within the ______ of the intestinal tract, peyer’s patches are closely associated with ________ cells, which are specialized antigen-capturing cells that transport antigens from the lumen to peyer’s patches.

Answer 26

Ileum

Microfold (M)

Question 27

T/F: Only in both rabbits and rodents, peyer’s patches are located randomly throughout the duodenum and jejunum, but all peyer’s patches undergo involution.

Answer 27

False, they are located in the jejunum and ileum in rodents and rabbits

Question 28

_____________ lymphoid aggregates that are scattered through mucosal surfaces of the body, but predominantly __________ mucosa, which is both an ________ and ________ site.

Answer 28

Non-encapsulated
Intestinal
Inductive
Effector

Question 29

Mucosal-associated lymphoid tissue makes up a _____ portion of total lymphoid tissue.

Answer 29

Large, major, etc.