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44 Cards in this Set

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Explain why the stmnt is false:
all Th cells express CD4 and recognize only ag associated with class II MHC molecules
CD4+ cells that recognize class II MHC mol.s func. as TH cells, whereas CD8+ cells that recognize class I MHC molc.s fn. as TC cells. However some functional TH cells express CD8 and are class I restricted, and some functional Tc cells express CD4 and are class II restricted. But these are exceptions to the general pattern
Explain why the stmnt is false:

the pluripotent stem cell is
one of the most abundant cell types in the bone marrow
the bone marrow contains few pluripotent stem cells, they constitute only about 0.05% of all bone-marrow cells
Explain why the stmnt is false:

activation of the macrophages increases their expression of class I MHC molecules, making the cells present ag more effectively
TH cells recognize ag associated with class II MHC molecules
Explain why the stmnt is false:

lymphoid follicles are present only in the spleen and lymph nodes
organized lymphoid follicles are also present in the tonsils, peyer's patches, and other mucosal-associated tissue
Explain why the stmnt is false:

infection has no influence on the rate of hematopoiesis
in response to infection, TH cells and macrophages are activated and secrete various cytokines that induce increased hematopoietic activity. The induced hematopoiesis expands the population of WBCs that can fight the infection.
Explain why the stmnt is false:

follicular dendritic cells can process and present ag to T lymphocytes
unlike other types of dendritic cells, follicular dendritic cells do not express class II MHC molecules and thus do not fn as ag presenting cells for TH cell activation. These cells, which are present only in lymph follicles, can trap circulating ab-ag complexes, this ability is thought to facilitate B-cell activation and the development of memory B cells
Explain why the stmnt is false:

all lymphoid cells have ag-specific receptors on their membrane
B and T lymphocytes have ag binding receptors, but a small population of lymphoid cells, called null cells, does not
Explain why the stmnt is false:

all vertebrates generate B lymphocytes in bone marrow
although many animals, such as humans and mice, generate B cells in bone marrow, others, such as some ruminants, do not
Explain why the stmnt is false:

all vertebrates produce B or T lymphocytes, and most produce both
so far, it has not been possible to demonstrate the presence of T or B cells in jawless fishes such as the lamprey and hagfish
State the latest common progenitor that gives rise to the following set of cells:

dendritic and macrophages
MYELOID PROGENITOR
State the latest common progenitor that gives rise to the following set of cells:

monocytes and neutrophils
GRANULOCYTIC-MONOCYTE PROGENITOR
State the latest common progenitor that gives rise to the following set of cells:

Tc cells and basophils
HEMATOPOIETIC STEM CELL
State the latest common progenitor that gives rise to the following set of cells:

Natural killer cells and B cells
LYMPHOID PROGENITOR
List the primary lymphoid organs and summarize their functions in the immune response
Bone marrow (bursa of fabricius in birds) > functions as site for B-cell maturation
Thymus > functions as site for T cell maturation
List the secondary lymphoid organs and summarize their fn.s in the immune response.
Spleen
lymph nodes
mucosal-associated lymphoid tissue (MALT) in various locations > includes the tonsils, peyer's patches and appendix, as well as loose collections of lymphoid cells assoc. with the mucous membranes lining the respiratory, digestive, and urogenital tracts.

ALL OF THESE ORGANS TRAP AG AND PROVIDE SITES WHERE LYMPHOCYTES CAN INTERACT WITH ANTIGEN AND SUBSEQUENTLY UNDERGO CLONAL EXPANSION
What are the 2 primary char.s that distinguish hematopoietic stem cells and progenitor cells?
Stem cells are capable of self-renewal and can give rise to more than one type of cell
Progenitor cells have lost the capacity for self-renewal and are committed to a single cell lineage. The commitment depends on their acquisition of responsiveness to particular growth factors.
What are the two primary roles of the thymus?
the generation and selection of a repertoire of T cells that will protect the body from infection
What do nude mice and humans with Digeorges's syndrome have in common?
both have a congenital defect that prevents development of the thymus...both lack circulating T cells and cannot mount cell-mediated immune responses
At what age does the thymus reach its maximal size?
during puberty in humans...during the adult years it gradually atrophies
Preparations enriched in hematopoietic stem cells are useful for research and clinical practice. In weissman's method for enriching hematopoietic stem cells, why is it necessary to use lethally irradiated mice to demonstrate enrichment?
The lethally irradiated mice serve as an assay system for multipotent HSCs, since only mice injected with these stem cells are able to reconstitute their hematopoietic systems and survive. As HSCs are successively enriched in a preparation, the total number of cells that must be injected to restore hematopoiesis and thus enable survival decreases
Explain the difference between a monocyte and a macrophage.
monocytes are the blood born precursors of macrophages...monocytes have a characteristic kidney-bean shaped nucleus and limited phagocytic and microbial killing capacity when compared to macrophages....macrophages are much larger and undergo changes in phenotype to increase phagocytosis, antimicrobial mechanisms (oxygen dependent and independent), and secretion of cytokines and other immune system modulators. Tissue-specific functions are also found in tissue macrophages.
What effect would removal of the bursa of Fabricius (bursectomy) have on chickens?
The bursa of Fabricius in birds is the primary site where B lymphocytes develop. Bursectomy would result in a lack of circulating B cells and humoral immunities, probably would be fatal
Some microorganisms (such as Neisseria gonorrhoeae, Mycobacterium tuberculosis, and Candida albicans) are classified as intracellular pathogens. Define this term and explain why the immune response to these pathogens differs from that to other pathogens such as Staphylococcus aureus and Streptococcus pneumoniae.
After phagocytosis by macrophages, most bacteria and fungi are destroyed and broken down , the resulting ag peptides are displayed along with class II MHC molecules on the cell surface, where they can induce TH cell activation and subsequent ab (humoral) response. In contrast, intracellular bacteria and fungi have various mechanisms for surviving in macrophages after phagocytosis. These bacteria thus do not induce an ab response.
Indicate whether each of the following statements about the spleen is true or false. If false explain:

it filters ags out of the blood
T
Indicate whether each of the following statements about the spleen is true or false. If false explain:

the marginal zone is rich in T cells, and the periarteriolar lymphoid sheath (PALS) is rich in B cells
F ( MARGINAL ZONE IS RICH IN B CELLS, AND PALS IS RICH IN T CELLS)
Indicate whether each of the following statements about the spleen is true or false. If false explain:

it contains germinal centers
T
Indicate whether each of the following statements about the spleen is true or false. If false explain:

it functions to remove old and defective rbcs
T
Indicate whether each of the following statements about the spleen is true or false. If false explain:

lymphatic vessels draining the tissue spaces enter the spleen
F (THE SPLEEN IS NOT SUPPLIED WITH AFFERENT LYMPHATICS)
Indicate whether each of the following statements about the spleen is true or false. If false explain:

lymph node but not spleen function is affected by a knockout of the ikaros gene
F (IN ADDN TO BEING ESSENTIAL FOR THE FORMATION OF NK CELLS, IKAROS IS ALSO ESSENTIAL FOR THE FORMATION OF T AND B CELLS. THEREFORE, ITS KNOCKOUT WOULD PREVENT LYMPH NODES AS SERVING AS SITES FOR THE GENERATION OF ADAPTIVE IMMUNE RESPONSES)
Describe the cell type:

common myeloid progenitor cells
give rise to RBCs
Describe the cell type:

Monocytes
circulating blood cells that differentiate into macrophages in the tissues
Describe the cell type:

Eosinophils
phagocytic cells important in the body's defense against parasitic organism
Describe the cell type:

dendritic cells
an antigen-presenting cell derived from monocytes that is not phagocytic
Describe the cell type:

kupffer cells
macrophages found in the liver
Describe the cell type:

lymphoid dendritic cell
an ag-presenting cell that arises from the same precursor as a T cell but not the same as a macrophage
Describe the cell type:

mast cells
WBCs that migrate into the tissues and play an important role in the dev. of allergies
Describe the cell type:

Neutrophils
generally first cells to arrive at site of inflammation
Describe the cell type:

M cells
Cells that are important in sampling ags of the intestinal lumen
Describe the cell type:

Bone marrow stromal cells
secrete colony-stimulating factors (CSFs)
Describe the cell type:

Lymphocytes
members of a category of cells not found in jawless fishes
Describe the cell type:

NK1-T cell
cells that sometimes recognize their targets with the aid of an ag-specific cell-surface receptor and sometimes by mechanisms that resemble those of natural killer cells
Describe the cell type:

microglial cell
phagocytic cells of the CNS
Describe the cell type:

myeloid dendritic cell
an antigen-presenting cell derived from monocytes that is not phagocytic
Describe the cell type:

hematopoietic stem cell
give rise to RBCs (and all other hematopoietic cells)