Question 1

Monocytes enter tissue and develop into:&#10;A) PMNs&#10;B) Mast cells&#10;C) Plasma cells&#10;D) Macrophages

Accepted Answer

Mast cells are located in the tissues, but they are a distinct cell type and do not develop from another circulating cell. Activated B cells develop into plasma cells. PMNs are found in the blood, and are a distinct cell type that does not develop from another circulating cell. Monocytes enter tissues and develop into the larger macrophages that either remain fixed in the tissue or move through the tissues searching for debris and pathogens.

Question 2

Which of the following congenital disorders results in defects in the thymus?
I- Nezelof Syndrome
II- DiGeorge Syndrome
III- Leukocyte Adhesion Deficiency

A) I only
B) III only
C) I and II
D) II and III
E) I, II, and III

I and II

Accepted Answer

Both Nezelof syndrome and DiGeorge syndrome are inherited disorders that result in a range of defects, but both result in abnormalities of the thymus that lead to T cell dysfunction. One distinction between the two disorders is that patients with Nezelof syndrome have normal parathyroid function, while those with DiGeorge syndrome have a defective parathyroid. Leukocyte adhesion deficiencies are inherited disorders that lead to impaired migration by immune cells to the site of infection due to lack of expression of adhesion molecules, and these disorders do not affect thymic function.

Question 3

Monocytes are primarily located in the:&#10;A) Liver&#10;B) Blood&#10;C) Spleen&#10;D) Lymph nodes

Accepted Answer

When monocytes migrate to tissues, such as the liver, they become macrophages. Specifically, macrophages in the liver are known as Kupffer cells. Monocytes can circulate through the spleen and lymph nodes, but the main cells in those organs are lymphocytes and macrophages. Monocytes primarily circulate in the blood.

Question 4

The granules in polymorphonuclear leukocytes (PMNs) play which of the following roles in the immune response?&#10;A) Assist in antibody production&#10;B) Kill cells infected with viruses&#10;C) Destroy phagocytosed bacteria&#10;D) Aid cells in ingestion of bacteria

Accepted Answer

The granules of PMNs contain substances, including lysozyme and myeloperoxidase, that are involved in killing and destroying pathogens that have been taken up by phagocytosis. This process occurs following ingestion of the pathogen. PMNs do not produce antibodies or kill virus-infected cells.

Question 5

Aged red blood cells are destroyed by macrophages in the:&#10;A) Tonsils&#10;B) Lymph nodes&#10;C) Peyer's patches&#10;D) Splenic red pulp

Accepted Answer

The splenic red pulp is the area where aged red blood cells are destroyed by macrophages, while the white pulp is the area where T and B cells interact with cells presenting antigen from blood-borne pathogens. The tonsils and Peyer's patches are both areas of mucosal-associated lymphoid tissue (MALT), which are areas that interact with pathogens that have breached the mucosal barriers, but have no role in red blood cell destruction. Lymph nodes serve a similar function to the spleen, acting as a filter for pathogens in the tissue. However, the lymph nodes do not have an area of red cell destruction as the spleen does.

Question 6

Phagocytosis is the main function of which of the following cell types?&#10;A) NK cells&#10;B) Basophils&#10;C) Eosinophils&#10;D) Macrophages

Accepted Answer

Macrophages ingest pathogens by phagocytosis. Eosinophils can phagocytose small parasites, but it is not their main function. Their main function is to degranulate on large parasites to cause damage and death of the parasite. Basophils and NK cells are not able to phagocytose pathogens at all.

Question 7

Immature thymocytes begin their initial cycle of proliferation in:&#10;A) The thymic cortex&#10;B) Hassall's corpuscles&#10;C) The germinal center&#10;D) The lymph node medulla

Accepted Answer

T cells begin maturation in the thymic cortex and migrate to the medulla to undergo further maturation and differentiation. Hassall's corpuscles contain degenerating cells in the thymus. B cells proliferate in the germinal centers in the cortex of the lymph node, and the medulla of the lymph node contains a variety of cells involved in facilitating antigen-antibody interactions.

Question 8

Which cell type contains granules that are specific for killing parasites?&#10;A) PMNs&#10;B) Eosinophils&#10;C) Macrophages&#10;D) Large granular lymphocytes

Accepted Answer

Eosinophils have large granules that contain substances, such as major basic protein (MBP) and eosinophilic cationic protein (ECP), that specifically target large parasites. Macrophages do not have granules. Large granular lymphocytes (LGLs) and PMNs have granules, but those granule components are used for purposes other than killing large parasites. LGLs mainly kill virus-infected cells and tumor cells, and the granules in PMNs aid in killing small pathogens, such as bacteria, that are ingested by phagocytosis.

Question 9

In positive selection, thymocytes undergo apoptosis when:
I-They do not interact with MHC molecules
II-They bind to MHC molecules with high affinity
III-They bind to MHC molecules with low affinity

A) I only
B) III only
C) I and II
D) II and III
E) I, II, and III

Accepted Answer

In positive selection, thymocytes that do not interact with MHC undergo apoptosis because they are nonreactive. Thymocytes that bind to MHC with high affinity also undergo apoptosis because they are considered autoreactive. Thymocytes that bind to MHC with low affinity are considered non-threatening and migrate deeper into the thymic cortex for further maturation.

Question 10

The __________________ serves as a filter to trap infections in the tissues.&#10;A) Spleen&#10;B) Thymus&#10;C) Bone marrow&#10;D) Lymph system

Accepted Answer

Tissue fluid drains into the lymphatic system and then circulates through the lymph nodes. Cells that have captured antigen for presentation remain in the lymph nodes to interact with B and T cells. The spleen serves a similar function, but for pathogens that are circulating in the blood. The bone marrow and thymus are involved in B and T cell maturation, but are not involved in facilitating interactions between antigen and lymphocytes.

Question 11

The main function of _______________ is to ingest and destroy bacteria.&#10;A) B cells&#10;B) Eosinophils&#10;C) Natural killer (NK) cells&#10;D) Polymorphonuclear leukocytes (PMNs)

Accepted Answer

The answer of The main function of _______________ is to...

Question 12

As a result of leukocyte adhesion deficiency, white blood cells cannot:&#10;A) Present antigen&#10;B) Release granules&#10;C) Perform diapedesis&#10;D) Phagocytose pathogens

Accepted Answer

The answer of As a result of leukocyte adhesion deficiency,...

Question 13

All T cells express which of the following CD markers?&#10;A) CD3&#10;B) CD4&#10;C) CD8&#10;D) CD16

Accepted Answer

The answer of All T cells express which of the...

Question 14

Which of the following cells is important for killing virus-infected cells?&#10;A) NK cells&#10;B) Basophils&#10;C) Monocytes&#10;D) Plasma cells

Accepted Answer

The answer of Which of the following cells is important...

Question 15

Hematopoiesis is the:&#10;A) Development of blood cells&#10;B) Development of cancer cells&#10;C) Development of immune cells&#10;D) Development of immune response

Accepted Answer

The answer of Hematopoiesis is the:&#10;A) Development of blood cells&#10;B)...

Question 16

B cells that are actively proliferating are located in the ________________ of the lymph node.&#10;A) Mantle layer&#10;B) Germinal center&#10;C) Medullary region&#10;D) Paracortical region

Accepted Answer

The answer of B cells that are actively proliferating are...

Question 17

Development of which cell type is impaired in DiGeorge syndrome? &#10;I- T cells&#10;II- B cells&#10;III- NK cells&#10;A) I only&#10;B) III only&#10;C) I and II&#10;D) II and III&#10;E) I, II, and III

Accepted Answer

The answer of Development of which cell type is impaired...

Question 18

What role does the T helper 1 (Th1) subset play in the immune response?&#10;A) Inhibits viral replication&#10;B) Causes target cell death of infected cells&#10;C) Assists B cells in the production of antibody&#10;D) Generates inflammatory responses to pathogens

Accepted Answer

The answer of What role does the T helper 1...

Question 19

The role of microfold (M) cells is to:&#10;A) Trap antigens&#10;B) Kill pathogens&#10;C) Present antigens&#10;D) Produce antibodies

Accepted Answer

The answer of The role of microfold (M) cells is...

Question 20

The main purpose of diapedesis is to:&#10;A) Aid neutrophils in granule release&#10;B) Capture antigens for presentation to lymphocytes&#10;C) Allow immune cells to travel to the site of infection&#10;D) Activate macrophages for more effective phagocytosis

Accepted Answer

The answer of The main purpose of diapedesis is to:&#10;A)...

Deck 1: Cells and Organs of the Immune System