1-14 Cohen Tissues And Organs Of Immune System

Front 1

The primary or ___ lymphoid tissues are in the ___ and ___ and are the sites of immune cell ___

Back 1

central
bone marrow and thymus
immune cell development

Front 2

The secondary or ___ lymphoid tissues are in what tissues/organs. These are the sites of .... (?)

Back 2

peripheral

spleen, lymph nodes, mucosal-associated tissue
mature cell residence and initiation of adaptive

immune responses

Front 3

Hematopoiesis is _____
most immature cells reside ____ to bone
they mature in _____
as they start to be matured they migrate toward ___ and exit the marrow via ___

Back 3

compartmentalized
nearest
islands of maturation
central sinus
central sinus

Front 4

Which section of the bone does the hematopoiesis occur in?

In this area there's a network of ___ and ___ cells which are the sources of ___ and ___

Back 4

The spongy bones toward the end. It creates 3D environment (whatever that means)

reticular and endothelial cells for growth factors and cytokines (drive proliferation and differentiation)

Front 5

The non-immune structural cells in the spongy bone have to ___ with the hematopoietic cells in order for them to ___

Back 5

physically interact for them to mature

Front 6

When you compare different cells in the marrow, which do you see at highest concentrations

Back 6

Cells going to granulocytes-> neutrophils, eosinophils, and basophils

Followed by lymphocytes and RBC's

Front 7

ID some key features on here-- what's happening where?

Back 7

bone trabeculae make pockets for the developing immune cells.
The dark regions: islands of hematopoiesis where they're developing
The lighter regions: sinusoids where the cells go, making their way to the central sinus

Front 8

What are we looking at, and how is it relevant to the hematopoietic story?

Back 8

Darker is hematopoietic part; lighter is sinusoid. They are separated by a layer of epithelium which the migrating cells have to get through similar to extravasation in inflammation

Front 9

How do you ID a neutrophil?

Back 9

multilobulated nucleus

Front 10

compare the two circled areas

Back 10

can tell by the nuclei mainly

Front 11

it is super duper important that the reticular cell infrastructure ___ developing immune cells to ...

The reticular cells can be referred to as ___

The reticular cells can communicate with progenitor cells via what mechanisms?

Back 11

physically contacts to drive maturation (he's said this 3 times already)

stromal cells

receptor-receptor or by releasing or showing (still attached) cytokines to interact with progenitor's receptors

Front 12

When would we use the stromal-progenitor interactions clinically?

Name a drug and its descriptor

Back 12

If pt is neutropenic (low levels making them susceptible to infection)

leukine (it's a GM-CSF: granulocyte monocyte- colony stimulation factor)

Front 13

Gross description of thymus and its location

It has ___ ___ within lobes, each consisting of an outer ___ and inner ___

Back 13

bi-lobed structure under sternum

(before this year started, I had always pictured the thymus being up in the neck-- I didn't realize how far down in the chest it was)

multiple lobules (like a functional unit) with a (darker) cortex and (lighter) medulla

Front 14

Where does the maturation of T cells occur within the thymus? What do you call the cells that left the bone marrow to go to the thymus to do this?

So what do the other parts do?

Back 14

thymocytes come in to do thymopoiesis development into mature T cells in the cortex of the lobules.

The cortical epithelial cells provide cell contact signals and growth factors

Front 15

Mature T cells leave the lobule and enter the blood via ...

Back 15

venules in corticomedullary junction

Front 16

As you get older your thymus shrivels up as fat replaces the parenchymal tissue which is really called _______ which causes ___

Back 16

age-related thymic involution
"immunosenescence"- there's still some of the tissue remaining but the functioning capacity decreases

Front 17

Which area is all the thymocytes going to mature t cells?

Just like in the bone marrow, the maturing cells migrate to ___ portions of the ___ and then go out.

The ___ contains many macrophages which ...

Back 17

cortex

lower portions of the cortex

medulla; they clean up debris

Front 18

At the top of the lobule cortex, the cells are dividing super rapidly but more than __% of them will die. They are trying to ___(generally described)____ but it's a very ___ process

Back 18

90%
trying to make an antigen receptor but it's a very inefficient process that makes a lot of mistakes

(also explains all the debris the macrophages in the medulla are eating)

Front 19

In more detail outline what the thymocyte goes into (what is on its surface) and decide to become either __ or __. Once they make that choice that put another molecule on their surface depending on their choice-- what is on each respective cell?

Back 19

CD3 and TCR (t cell receptor which recognizes antigen)

helper cell adds CD4
CTL (cytotoxic lymphocyte) adds CD8

Front 20

In the secondary lymphoid tissues, it's all about the mature immune cells....

Back 20

getting initiated. Before they were maturing.

Front 21

The spleen is a __ bed that takes out ___, and is the site of ___ immune response to ___ antigens. The spleen has ___ which penetrate the organ carrying ___ which break down into ___. They are encased in ___ which is called the ___

Back 21

Filtration bed taking out debris, and the site of adaptive immune response to blood-borne antigens. It has fibrous trabeculae which carry blood vessels which break down into central arterioles which are encased in T lymphocytes as the periarteriolar lymphoid sheath (PALS).

Front 22

From the PALS there are outpockets called ___ which are rich in ___. There are two types of these-- name them, what the difference is, and how you can see it histologically.

Back 22

lymphoid follicles rich in B cells.

primary lymphoid follicle - resting B cells (just purple), no active immune response

secondary lymphoid follicle - outer mantle of resting B cells (purple ring) with a central germinal center containing proliferating B cells (white center).

(In the picture, he's marked the red CA = central arteriole surrounded by PALS and then off to the right circled again is a secondary lymphoid follicle)

Front 23

Breaking down a secondary lymphoid follicle: looking at this, do you know what the different areas are and what they contain?

Back 23

The marginal zone has B cells resting and is darker. If this were a primary lymphoid follicle, everything inside its boundaries would be dark. This is secondary, so the granular center is present lighter in color with active B cells. CA central arteriole and PALS towards bottom. PALS has T cells.

Front 24

Process of circulating Ag into the spleen-- they come in to the spleen in the ___ via the ___. Most of them will course right past the follicle and dump into the ___ which ____ them. The parts that go into the follicle get dumped into the ___. There the lymphocytes try to find their Ag. If they do find it, they ___.

Back 24

blood via central arteriole.
dump into the red pulp which just eats all the debris including the Ag
perifollicular zone
If they find the Ag they migrate-- depending if they are B/T they go different places.

Front 25

Lymph nodes are the sites of ___ immune response to ___ antigens. The lymph enters the node via ___ that are kind of at the head of the node. The cells get in via ___. Within the node, there are areas rich in B and T cells and there can be also be ___ just like in the spleen which differentiate primary and secondary follicles.

Back 25

tissue-borne
afferent lymphatic vessel
the blood supply
germinal center (he circled three spots- furthest right is a primary; the other two secondary).

Front 26

The main difference between how the spleen and lymph nodes work is...

Back 26

how the Ag goes in. The system inside is basically the same.

Front 27

In the lymph: what is a subcapsular sinus? What's in it?

Back 27

The afferent lymphatics thereby the antigens get dumped into it. It contains a lot of macrophage and dendritic cells (which are responsible for presenting antigen to T cells)

Front 28

In the medulla of the lymph node, it is rich in...

Back 28

macrophages and plasma cells.
The plasma cells can sit here comfortably and pump out antibodies.

Front 29

Where do the cells extravasate from the vessels to go into the lymph node?

Back 29

postcapillary high endothelial venule

Front 30

Mucosal-associated lymphoid tissue is referring to what?

Back 30

Under the epithelium of all mucosal tissue sites are lymph node like tissue. It has immune cells- both effector and naive cells.

Front 31

How do Ag get into the mucosal-associated lymphoid tissue?

Back 31

Just come from the lumen of the organ.

Front 32

There are diffuse immune cells in this region just below the epithelium.

Back 32

lamina propria

Front 33

In the ileum, there are regions loaded with lymphoid follicles. These are called what and what do they do? How does the Ag get in?

Back 33

Peyer's patches

The Ag comes in through the top from the lumen via M cells, a special epithelium cell. It puts the Ag in and dendritic cells take them to start the immune response.