Lymphoid Tissue Flashcards

1
Q

Why are the respiratory and genitourinary tract prone to invasions by pathogens?

A

lumen is exposed to the external environment. (remember mucosa surfaces are vulnerable to infections)

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

3 types of lymphocytes are what?

A

1) Nk cells
2) T cells
3) B cells

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

Which lymphoid tissue is not surrounded by a capsule and why does it look like it is?

A

Diffuse lymphoid Tissue

Because its a lot of lymphocytes clustered together possibly forming nodules in the lamina propia.

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

Peyers patches are examples of what kind of lymphoid tissue?

A

Diffuse lymphoid tissue or MALT (mucosa associated lymphatic tissue)

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

The initial site of immune response is what kind of Tissue?

A

Diffuse lymphoid Tissue

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

Name the capsulated lymphoid organs:

A

Spleen
Thymus
Lymph node

(remember tonsils are partially encapsulated)

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

What makes up the framework in both lymphoid

tissue and lymphoid organs except the thymus?

A

Reticular fibers secreted by reticular cells

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

In the thymus what forms the framework?

A

epithelial reticular cells

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

What is Lymphocyte recirculation?

A

The continuous movement of T and B cells from one location to another they are never anchored in the lymphoid tissue or organ

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

Why do people present with swollen lymph nodes?

A

immune system has been activated to fight an invader so there is an increase of lymphocytes within the node

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

Where do B lymphocyte become immunocompetent?

A

Red Bone Marrow

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

Where do CFU-L cells from the bone marrow go to produce immunocompetent T cells

A

Thymus

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

Why does the cortex stain darkly as compared to the medulla?

A

The cortex has more lymphocytes

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

Why is the medulla Stain lighter?

A

Because there is less lymphocytes there ( REMEMBER 95% of lymphocytes die by apoptosis before they get to the medulla)

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

The cytoplasm of the childs thymus contain what?

A

Tonofilaments/Keratin filaments

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

What is the embryological origin of the ERCs

A

Endoderm

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

What is the embryological origin of the T lymphocytes

A

Mesoderm

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

Thymosin, Thymulin and Thymopoetin are secreted by what?

A

Epithelial Reticular Cells

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

The blood thymus barrier protects the immature thymocytes from antigens. What creates the blood thymus barrier?

A

type 1 ERCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Fibroblasts in the thymus form what?

A

Capsule and trabeculae

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

All APCs contain what kind of molecules on them?

A

Class II MHC

22
Q

In the medulla what cells are involved in the destruction of the thymocytes that recognize self?

A

Dendritic cells

23
Q

a rounded globular mass of cells within the medulla is called what?

A

hassals corpuscle

24
Q

Hassals corpuscles are made from what?

25
The failure the thymus to develop properly is called what? What causes this to occur?
Di Georges syndrome faulty development in the 3rd and 4th pharyngeal arches
26
Germinal centers are found in which lymphoid nodules?
secondary ( remember it stains lighter because the B cells are proliferating and switch their class of antibodies)
27
What cell would you find within the germinal center?
Follicular dendritic cell (FDC)
28
What is the function of the Follicular Dendritic Cell?
they can trap antigens for months or years and They form a network to attract and organize lymphoid cells
29
The embryological origin of FDCs are:
Mesenchymal
30
Why are the FDCs different when it comes to their comparison with APCs?
They dont have MHC II molecules.
31
The accumulation of lymphatic tissue within the ileum is called what?
peyers patch
32
The primary function of M cells?
they transfer antigens from the lumen by phagocytocis or pinocytosis without processing them to the lymphocytes and macrophages lying deep within. * THEY ARE NOT APCs
33
How do foreign substances reach the palantine tonssils?
Crypts
34
Which tonsil will you not find crypts and lies beneath pseudostratified ciliated columnar epithelium?
pharyngeal tonsils
35
A single crypt that is lined by non-karitinized stratified squamous epithelium can be found where?
Lingual tonsil
36
In the lymph node where do must lymphocytes enter through?
HEVs
37
The endothelial cells lining the venules are what?
cuboidal
38
Homing is referred to as what?
the movement of T and B lymphocytes through the HEVs
39
Where are B cells concentrated within the spleen or lymphnode?
Outer cortex
40
Where are T cells concentrated?
paracortex
41
The subscapular sinus is composed of what?
Loose network of reticulum cells and fibers
42
The main cell type within the medullary cord is what?
Plasma Cells and B cells
43
Sinusoids and Splenic cords ( bilroth) are found where in the spleen?
Red pulp
44
The periarterioal lymphoid sheath is found where?
Within the white pulp
45
White pulp functions as what?
Location where B cell clones are found along with T-cells that come from the PALS
46
What is the role of the marginal zone?
To trap the antigen from circulation to present it to the lymphocytes of the spleen
47
In the spleen where do the antigens enter?
Through the blood ( remember antigens enter through the lymph in the lymph node)
48
Describe the Path of the pathogen as it enters the spleen.
Antigen enters through the blood, and goes toward white pulp through trabeculated arteries and marginal sinus>>>>>> APCs detect them by the PALS>>> T cells interact with B cells>>> B cells proliferate and differentiate into plasma>>> plasma secretes Igs to the blood circulation
49
Describe the path of open circulation.
Blood from white pulp go to >>>penicillar arteries>>>sheathed capillaries>>> percolate in the red pulp cords>>> red pulp sinusoids>> veins
50
Stave cells line what?
Splenic venous sinus
51
How are the damaged RBCs removed when someone does not have a spleen?
macrophages in the liver and bone marrow
52
What lymph organs contain efferent lymph vessels?
Thymus, Spleen, Tonsils