Lymphoid tissue Flashcards

1
Q

What are primary lymph tissues?

A

those sites that support the generation of functionally mature, but antigen naïve, T and B cells

(bone marrow and thymus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are secondary lymph tissues?

A

locations where naive lymphocytes reside while waiting to be activated by their specific antigens. These funnel antigens through them.

(e.g. Lymph nodes, Peyer’s patches, spleen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are tertiary lymph tissues?

A

sites of the body where the elimination of antigen takes place (the “battlefield”)

e.g. skin, GI, lungs, vagina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the cells in bone marrow responsible for the generation of new cells?

A

Pleuripotent stem cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The hematopoietic compartment of the marrow is supported by what?

A

the bone marrow stroma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The bone marrow stroma is composed of what? (3)

A

reticular stromal cells, macrophages, and adipocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the function of stromal cells in the stromal tissue of bone marrow?

A

provide for cell-to-cell contact as well as soluble factors required for the differentiation of the hematopoietic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where do B lymphocytes mature? From where to where?

A

Mature from outer to inner part of bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The differentiation of immature B cells to mature B cells takes place where?

A

Secondary lymphatic tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where do T lymphocytes originate from? Where do they go to mature?

A

Bone marrow, go to thymus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Stem cells differentiate into what precursor of T cells?

A

Prothymocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Once in the thymus, the prothymocytes are called what?

A

Thymocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where are autoreactive T cells deleted?

A

Thymus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why does it not matter that the thymus degenerates in adults?

A

Once the T lymphocyte repertoire is established, T cell immunity is maintained by long-lived memory T cells and division of mature peripheral T cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Do thymocytes express TCR, CD3, CD4, or CD8 proteins?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

True or false: during the development of thymocytes, there is a point where they express both CD4 and CD8

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Once the T lymphocytes reach the thymus, what proteins are they expressing?

A

the TCR, CD3 and either CD4 or CD8 proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are Hassall’s corpuscles?

A

Graves of dead thymocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What cells are the “teachers” of thymocytes? How do they do this (3)?

A

Cortical epithelial cells, which provide:

  1. Cell-to-cell contact
  2. Cytokines
  3. Peptide hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What ensures that lymph only moves in one direction?

A

One-way valves on lymph vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What tissues are the main immunologic responders?

A

Lymph nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The thoracic duct empties its contents into what?

A

Left subclavian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What vessles bring in lymph to lymph nodes? Away?

A
Afferent = bring in
Efferent = take out
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The cortex of lymph nodes has what type of cells? Paracortex? Medulla?

A

Medulla and cortex = B cells

Paracortex = T cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the significance of B cells having to migrate past T cells in lymph nodes?
Increases chance that an activated B cell reacts with a Th cell
26
What are the B-cell rich areas of lymph nodes called?
Follicles
27
Primary follicles in lymph nodes contain what two cell types?
B cells and dendritic cells
28
Secondary follicles in lymph nodes contain what type of cells?
antigen-activated B cells and follicular dendritic cells
29
True or false: Dendritic cells are present throughout the T cell-rich areas
True
30
Where are macrophages found in lymph nodes?
mainly in the marginal sinus
31
What happens when lymph nodes encounter an antigen, and are enlarged?
Primary follicles morph into secondary ones
32
Do lymph nodes that have been exposed to antigen totally morph back to their original state?
Yes
33
What is the function of called high endothelial venules in lymph nodes?
Express specific adhesion molecules which lymphocytes can bind using homing receptors to enter the lymph node from the blood
34
What is the general role of the spleen? How does it do this?
Filter blood exposes lymphocytes in white pulp to blood-borne antigens
35
Surrounding the central arteries and penicilliary arterioles in the spleen is what?
a cuff of lymphocytes, most of which are T cells (PALS)
36
Does splenic lymphoid tissue have high endothelial cells?
No, but has analogous structures
37
Most pathogens that we encounter occur where?
at mucosal sites such as the lungs, gastrointestinal tract and genitourinary tract.
38
Do MALTs have specific B and T cell regions?
No
39
What are Peyer's patches?
MALTs in the ileum, where B cell follicles are surrounded by a zone that is rich in T cells
40
Are there high endothelial venules in Peyer's patches?
yes
41
What is the function of the "M" cells in Peyer's patches? What gives them this ability?
transport proteins and microorganisms from the intestinal lumen into the lymphoid tissue Have microfolds
42
What allows B and T cells to continue to survive despite not having encountered antigens?
secondary lymphoid tissues provide sustaining signals to lymphocytes
43
What directs T cells, B cells, marcophages, and dendritic cells to their location within a lymphoid tissue? What produces these?
Chemokines, produced by stromal cells of lymphoid organs
44
What is the general function of tertiary lymphoid tissue?
to complete an immune effector response
45
Can any tissue be a tertiary lymphoid tissue? Which tissues are generally tertiary lymphoid tissues?
Yes, but generally skin and mucosa
46
What allows for the deposition of macrophages, B cells, T cells etc in specific tissues?
Adhesion proteins that are expressed on blood vessel endothelial cells
47
What are the dendrictic cells that are present in the stratum spinosum of the skin? What happens when these cells encounter an antigen?
Langerhans cells They stop expressing cell adhesion molecules and migrate out
48
the vast majority of B and T lymphocytes that are present at tertiary lymphoid sites are of what type?
Memory cells
49
What must happen to Langerhans cells before they can present antigen to T cells?
Migration to lymph node and maturation to mature dendritic cell
50
Antigen that has been carried from the tissues to the lymph node via the lymph encounters what cells?
Macrophages but also other antigen presenting cells
51
B lymphocytes that migrate into the lymph node have to pass by what cells on their way to the B cell-rich follicles?
T helper cells
52
What can happen to B cells that express antigens to T cells in lymph nodes?
Differentiate into plasmablasts right away to express less specific antibodies or migrate to B cell follicles to proliferate
53
What type of cells are in the germinal center of secondary follicles?
proliferating, antigen-specific activated B cells
54
What is the time frame for B cell proliferation when activated?
6-8 hours
55
What ultimately happens to the B cells that form the germinal center of lymph tissue?
differentiate into plasma cells and secrete high affinity antibody OR become memory cells
56
What are the two major sites of antibody production/excretion?
Medulla of lymph node Bone marrow
57
Why do lymphocytes have to be circulated in the body?
. Since a relatively few copies of naïve lymphocytes exist for any given antigen, recirculation allows a greater probability for those lymphocytes to contact an antigen presenting cell and become activated.
58
What is lymphocyte homing? What molecule is this process dependent on?
the propensity for lymphocyte populations to take up residence preferentially in certain lymphoid organs or tissues Homing is dependent upon specific “addressins” expressed by lymphocytes that allow the cells to bind to the site that specifically binds those addressins.
59
What is the migratory pattern of Memory cells, and why is it different from naive lymphocytes?
Tend to circulate or accumulate in tertiary tissue, because they need to be in places where antigen is encountered
60
. An IgA response that occurred in a lymph node or in the skin would not be optimally effective. Why?
IgA is specialized for mucosal secretions.