University Of Alberta Medicine 10/10 Cells And Organs Of Immune System

Front 1

What does hemopoietic mean?

Back 1

Derived from the bone marrow.

Front 2

Where are hemopoietic cells found in the embryo, fetus, and adult human?

Back 2

The yolk sac, liver, and bone marrow respectively.

Front 3

From what type of cell do hemopoietic cells originate?

Back 3

A pluripotent stem cell.

Front 4

What causes hemopoietic stem cells to differentiate into different types of cells?

Back 4

Growth factors (cytokines).

Front 5

What are the two main types of lymphoid cells?

Back 5

B cells and T cells.

Front 6

Describe the maturation process of T cells.

Back 6

They begin as pluripotent stem cells, of course, and that becomes a lymphoid stem cell. This becomes a T progenitor, which migrates to the thymus and becomes a thymocyte (or pre-T cell). These develop a variety of antigen receptors, and the useful cells are selected to circulate in the bloodstream.

Front 7

Describe the maturation process of B cells.

Back 7

They begin as pluripotent stem cells, of course, and that becomes a lymphoid stem cell. This becomes a B progenitor, which expresses a certain antibody specificity. The useful B cells are chosen to circulate in the blood.

Front 8

Besides producing antibodies, what is the other major function of B cells?

Back 8

It is to be an antigen-presenting cell, ie. a cell that digests antigen and presents fragments complexed with MHC Class II for T-cell destruction.

Front 9

Describe the phases that a lymphocyte goes through after it is activated by antigen.

Back 9

It moves out of Go phase into G1, and then into S phase, where it is called a lymphoblast. Then it goes into M phase, where it goes through several rounds of cell division and enlargement, and eventually it divides into effector cells and memory cells.

Front 10

What does CD stand for? What is the clinical significance of this term?

Back 10

It stands for "cluster of differention" markers. These markers are different antigens on the surface of lymphocytes that allow us to distinguish between the different types.

Front 11

What CD's are used to distinguish Th cells and Tc cells?

Back 11

CD4 markers are found on Th cells, and CD8's are found on Tc cells.

Front 12

Describe what is known about NK cells.

Back 12

They are large, granular lymphocytes that don't bind antigens like B and T cells. They are cytotoxic for some virus- or tumor-infested cells, but we don't understand their receptors well.

Front 13

When it comes to immune cells, they can come from the lymphoid lineage or the _____________ lineage.

Back 13

myeloid

Front 14

How are myeloid cells distinguished from each other?

Back 14

By appearance or by reactivity to histological staining.

Front 15

Generally speaking, what do myeloid cells do, and how are they regulated?

Back 15

They are the major effector cells of the immune system, and are regulated by T and B cells during an immune response.

Front 16

What are monocytes a precursor to?

Back 16

Macrophages.

Front 17

What do macrophages do?

Back 17

They are large, adherent, phagocytic cells. They kill stuff using oxygen radicals and nitric oxide. They use antibody and complement receptors to identify pathogens. They are excellent APC's.

Front 18

What do the granules in granulocytes do?

Back 18

They released toxic mediators when triggered.

Front 19

What are the three types of granulocytes? How do they stain with H & E?

Back 19

Neutrophils (intermediate between pink and blue), eosinophils (blue), and basophils (pink).

Hint 19

Neutrophils = neutral color.
Basophils = Boys can wear pink.

Front 20

What do neutrophils do?

Back 20

They are the most abundant type of granulocyte. They infiltrate and attack infectious agents in the tissue. They use antigen receptors, like macrophages, but they are different in that they always are consumed in the phagocytic process.

Hint 20

Not NEUTRal - they go all in, and die in the process.

Front 21

What do eosinophils do?

Back 21

They carry the Major Basic Protein, are phagocytic, and are important in parasite defence and asthma.

Hint 21

Chant and shout - "Eee-os; P-P-P-A!"

Front 22

What do basophils do?

Back 22

They are similar to neurophils, and can bind IgE antibody via Fc receptors.

Front 23

What do mast cells do?

Back 23

They are also packed with granules, including ones with histamine. They also have IgE receptors, and these promote a number of mediators, including prostaglandins. This can be a response to parasites, but also causes allergic reactions.

Hint 23

a HIPPA would break the mast on your ship - Histamine, IgE receptors, Prostaglandins, Parasites, Allergies.

Front 24

What are Fc receptors?

Back 24

Receptors that bind the Fc region of an antibody (which is often attached to a pathogen) and cause it to be phagocytized.

Front 25

What do dendritic cells do?

Back 25

They are somewhat phagocytic, but they are best at being APC's. They get antigen partly from phagocytosis and partly through Fc receptors. They are an important part of the primary immune response, because they have high levels of MHC Class II, and also the important B7 molecule.

Hint 25

Some of Dis, some of Dat.

Front 26

How do myeloid cells obtain antigen-specific receptors?

Back 26

They attach to antibodies, and this gives them a sampling of all the antibodies in the serum.

Front 27

What is the major difference between necrosis and apoptosis when it comes to the inflammatory response?

Back 27

Necrosis spills the contents of the dying cell, causing inflammation. Apoptosis is a programmed cell death, and does not spill the contents or cause inflammation.

Front 28

What are the primary lymphoid organs? the secondary? What is the difference?

Back 28

The thymus and bone marrow are primary organs, where cells are generated for the immune response. All other lymphoid structures are secondary structures, and are where immune responses occur.

Front 29

Where do maturing T cells undergo mitosis?

Back 29

In the cortex of the thymus.

Front 30

What is Di George's syndrome? What are its effects?

Back 30

It is the absence of the thymus. It makes people immunodeficient, but other places can direct the maturation of T cells.

Front 31

What are plasma cells?

Back 31

Large, terminally differentiated B cells that secrete antibodies in great quantities.

Front 32

What is the purpose of the lymph nodes?

Back 32

To serve as a collecting center for stuff that is entering the body through the lymphatic system.

Front 33

What is the purpose of the spleen?

Back 33

To serve as a collecting center for antigens that are entering the body through the blood stream.

Front 34

What are common traits between the lymph nodes and the spleen?

Back 34

They both have germinal centers that expand during immune responses, and they are both structured to give maximum exposed of antigens (captured by APC's) to T and B cells, allowing appropriate activation and proliferation of these cells.

Front 35

Where are some places that a lymphocyte will go and not get recirculated?

Back 35

Bone marrow, epithelial surface, and the peritoneum.

Front 36

Where are some places the lymph nodes can receive lymph from?

Back 36

The blood lymphocyte pool, mostly, but also from the afferent lymph, which comes from the liver, brain, extralymphoid tissue, and muscosal epithelia.

Front 37

What are the three layers of a lymph node? What kind of cell(s) predominate(s) in each?

Back 37

The cortex (macrophages, dendritic cells, and B cells), the paracortex (macrophages, dendritic cells, and Th (helper) cells), and the medulla (antibody-producing plasma cells).

Front 38

Describe the a) blood vessel system; b) red pulp; c) white pulp; and d) marginal zone of the spleen.

Back 38

a) The splenic artery and vein come out at the same point, branching down to small arterties and back up to sinusoids which drain back into the large splenic vein.
b) The red pulp is erythrocyte-filled and surrounds the sinusoids.
c) The white pulp forms a sheath (PALS) around the arterioles, containing T cells.
d) The marginal zone is close to the PALS, and contains lots of B cells in various stages of development.

Front 39

What is the function of the MALT (musocal-associated lymphoid tissues)?

Back 39

It protects musocal surfaces (externally-secreting) from pathogens by IgA-bearing B lymphocytes, and a high concentration of T cells.

Hint 39

MALTs have a consistency like mucus.

Front 40

What leukocytes are found in the skin? What immune events happen when the skin is pentrated?

Back 40

The skin contains mostly dendritic-like Langerhans cells. When the skin is pentrated, these cells leave the epidermis and carry antigens to the draining lymph node, which stimulates a T cell response.

Front 41

What does the RES (reticuloendothelial system) do?

Back 41

It contains fixed phagoctyic cells to digest particulate matter that enters the body, and is found in the liver, spleen, lymph nodes, lungs, and placenta.