Microenvironment

Question 1

Bone marrow in the large bones is a major site of ______ in adults

Answer 1

Hematopoiesis

Question 2

In the developing fetus, hematopoiesis occurs in the ____

Answer 2

Yolk sack, AGM region, placenta, and fetal liver

Question 3

Provide support for HSC growth and development

Answer 3

Stromal cells

Question 4

Generate bone and control HSC differentiation

Answer 4

Osteoblasts

Question 5

Line the blood vessels, regulate HSC differentiation

Answer 5

Endothelial cells

Question 6

Connect cells to bone and blood vessels via long processes (arms)

Answer 6

Reticular cells

Question 7

Can control the release of HSC from the bone marrow

Answer 7

Sympathetic neurons

Question 8

HSC move from _____ niche to the _____ niche as they mature

Answer 8

Endosteal, vascular

Question 9

Mature lymphoid and myeloid cells can re-circulate between the ___ and ______________

Answer 9

BM, and secondary immune organs

Question 10

T cells mature in the _____

Answer 10

Thymus

Question 11

Does the number of thymocytes increase or decrease as they mature?

Answer 11

Decrease

Question 12

What are the two important stromal cells for thymocyte development?

Answer 12

• Cortical thymic epithelial cells (cTEC)
  -Medullary thymic epithelial cells (mTEC)

Question 13

What stromal cells enable positive selection?

Answer 13

cTEC

Question 14

What stromal cells enable negative selection?

Answer 14

mTEC

Question 15

How do immune cells interact with pathogens and become activated?

Answer 15

1. Leukocytes move from the circulation to the site of infection
2. Specialized organs trap antigens: spleen, lymph nodes, peyer’s patches

Question 16

Lymph nodes trap __________ antigens

Answer 16

Tissue borne

Question 17

Spleen traps _______ antigens

Answer 17

Blood borne

Question 18

How might exercise improve immune function?

Answer 18

1. Increased movement of lymph through the lymphatic system
2. Increased blood circulation

Question 19

Has a highly organized structure, B cell zones and T cell zones, follicular DC maintain follicular and germinal center structures

Answer 19

The lymph node

Question 20

Antigen enters via the __ lymphatics

Answer 20

afferent

Question 21

Where does the antigen empty?

Answer 21

Subcapsular sinus

Question 22

What is the antigen trapped by? What does it migrate through?

Answer 22

APC, migrates through the LN OR resident

Question 23

What are the steps of the T cells experience?

Answer 23

1. Ag enters via the afferent lymphatics
2. Empties into the subcapsular sinus
3. Trapped by APC; either migrating through the LN or resident
4. Naive T cells enter the LN from the blood via the high endothelial venules
5. Spend 16 to 24 hours in the LN browsing antigen on APC
6. a) Leave via efferent lymphatics if don’t find an Ag match
   or b) if find an Ag match, will stay in the node where it proliferates and differentiates into effector cells (kill or direct the killing)

Question 24

In the paracortex (T cell zone):

Answer 24

The fibroblast/ follicular reticular cells (FRC) create processes and conduits to allow T cells to interact efficiently with APCs

Question 25

What are the steps of the B cells experience?

Answer 25

First 3 steps same as T cell 4. Enter the LN via HEVs 5. Migrate through the paracortex into the follicles 6. a) Leave via efferent lymphatics if no Ag match b)if encounter Ag, becomes partially activated and internalizes Ag 7. Moves to paracortex to allow full activation by interacting with T cell 8. Some B cells re-enter follicle and establish the germinal center (aka secondary follicle). GC supports the generation of B cells with increased affinity (binding ability) for Ag 9. Some B cells become plasma cells; reside in the GC or in the bone marrow

Question 26

Which cell depends on the follicular reticular conduit system?

Answer 26

T cell

Question 27

All Ags and cells enter via the splenic ____ and leave via the splenic _

Answer 27

artery, vein

Question 28

Is healthy mucosa smooth or bumpy?

Answer 28

Bumpy

Question 29

What are Langerhans cells?

Answer 29

are a unique population of tissue-resident macrophages that form a network of cells across the epidermis of the skin, but which have the ability to migrate from the epidermis to draining lymph nodes