Organs Of The Immune System

Question 1

Central lymphoid tissues

Answer 1

• bone marrow
• thymus
• fetal liver

Question 2

Peripheral lymphoid tissue

Answer 2

• spleen
• lymph nodes
• MALT

Question 3

Secondary lymphoid organs

Answer 3

• maturation and activation of lymphocytes
• drain antigen material from tissues and organs

Question 4

Primary lymphoid tissue

Answer 4

• development of lymphocyte

Question 5

Internal lymphoid organs

Answer 5

• thymus
• bone marrow
• spleen
• lymph nodes

Question 6

Surface lymphoid organs

Answer 6

• salivary glands
• respiratory tract
• mammary glands
• intestine
• urogenital system

Question 7

Sources of lymphocytes

Answer 7

• yolk sac
• bone marrow
• fetal liver

Question 8

Sites of lymphocyte dev. (Primary organs)

Answer 8

• peyer’s patches
• thymus
• bursa
• bone marrow

Question 9

Sites where lymphocytes respond to antigens

Answer 9

• peyer’s patches
• bone marrow
• tonsils
• spleen
• lymph nodes

Question 10

Cell division takes place close to ___

Answer 10

Bone spicules & cytokine-rich ecm

Question 11

Mature cells are located ____ & released into ____

Answer 11

Closer to sinus lining cells; venous sinus when mature

Question 12

Thymus

Answer 12

• first lymphoid organ to dev. In fetus
• largest at puberty, then involution occurs
• outer cortex: thymocytes (immature lymphoid cells)
• inner medulla: mature t cells

Question 13

Hassal’s corpuscles

Answer 13

Function unknown

Question 14

Thymic epithelial cells

Answer 14

• produce hormones that may have a role in t cell maturation

Question 15

Hormones of thymus

Answer 15

• trophic hormone
• thymosin-a
• thymopoeitin
• thymulin
• thymus humoral factor

Question 16

Positive selection

Answer 16

T cells w/ receptors for intermediate affinities

Question 17

Negative selection

Answer 17

Auto-reactive t cells (recognize self antigens)

Question 18

Fewer than ___% thymocytes leave thymus

Answer 18

5

Question 19

Thymic involution

Answer 19

• physiologic
• age related
• decrease of ce

Question 20

Thymic atrophy

Answer 20

Stressful/pathological conditions (increase in corticosteroids)

Question 21

Major functions of lymph nodes

Answer 21

• trap antigens
• provide organized area for antigen presentation
• signals to maintain lymphocyte survival
• initiation of adaptive response
• lymphocytes cross into lymphatics by interacting with HEVs

Question 22

Lymph nodes in pigs

Answer 22

Cortex is inner

Medulla outer

Question 23

Follicles in lymph node

Answer 23

• primary follicle
• secondary follicle: germinal center

Question 24

Outer cortex of lymph node cell type

Answer 24

Aggregation of b cells

Question 25

Paracortex of lymph node

Answer 25

T cells

Question 26

Para cortex parts

Answer 26

- medullary cord: b cells, plasma cells, macrophages -medullary sinuses: lymph, macrophages, granulocytes, deliver lymph to efferent lymph vessels

Question 27

Microorganisms in spleen

Answer 27

- phagocytosed by fixed macrophages and dendritic cells - encounter b-lymphocytes - presented to t-lymphocytes

Question 28

Spleen

Answer 28

- no division of compartments (no cortex or medulla) - white pulp: b and t lymphocytes, macrophages, antigen presenting cells - red pulp: reticular fibers and cells, monocytes/macrophages, vascular spaces

Question 29

Chicken thymus

Answer 29

- 6-7 lobes bilaterally - lobes by jugular v. - cortical and medullary regions don’t have clear boundary - cellular depletion and involution of bursa and thymus happen as bird matures

Question 30

Immunological differences between birds and mammals

Answer 30

- mammals don’t have bursa of fabricius - avian many thymus lobes, mammals 2 - avians lack lymph nodes - avians may have IgD and Ige while mammals have all 5 Igs - Avians lack IgG subclasses

Question 31

Thymectomy and bursectomy effect on no. Of circulating lymphocytes

Answer 31

- thymectomy: decrease - bursectomy: negligible

Question 32

Graft rejection

Answer 32

- thymectomy: decrease - bursectomy: not reduced

Question 33

Cell-mediated cytotoxicity

Answer 33

- thymectomy: decrease - bursectomy: not reduced

Question 34

Serum immunoglobulins

Answer 34

- thymectomy: slight decrease - bursectomy: strong decrease