chapter 2 Flashcards
have the ability to differentiate into many types of blood cells
Hematopoietic stem cells (HSCs)
Why type of HSC do red and white blood cells develop from during hematopoiesis?
pluripotent
Where does hematopoiesis occur in adult vertebrates?
bone marrow
What are the 4 main types of cells that develop from common myeloid progenitors?
RBC, monocytes, granulocytes, and megakaryocytes
Migrate into tissues and differentiate into macrophages―function to repair/remodel, destroy pathogens, present antigens
monocytes
HIGH degree of function as “ingesters” of antigens, followed by presentation to naïve T lymphocytes for initial activation
dendritic cells
granulocytes that cause harm to pathogens
neutrophils
granulocytes that promote inflammation/allergies
basophils/mast cells
granulocytes that function in antiviral/antiparasite activity
eosinophils
What are some common characteristics of granulocytes?
-all have multilobed nuclei
-their cytoplasm is replete with granules
What is the function of megakaryocytes?
to form platelets
cell fragments placed into circulation for
clotting
platelets
what are macrophages and neutrophils specialized for?
phagocytosis
how do macrophages present antigens to T cells?
via Major Histocompatibility Complex molecules
Immature _______________ capture antigen, then mature
and migrate out of that location to another to present
antigen to ____________ cells
-dendritic cells
-B cells
What are the most potent antigen-presenting cells (APC) for
activating naïve T cells?
dendritic cells
What are the three main types of cells develop from the common lymphoid progenitor?
-B lymphocytes
-T lymphocytes (NKT)
-natural killer cells
Cell membrane proteins expressed by cells of the
immune system are referred to by _________________nomenclature
cluster of differentiation (CD)
CD3?
Signal transduction element of T-cell receptor
CD4?
-helper T cells
-Adhesion molecule that binds to MHC class II molecules;
signal transduction
CD8?
-cytotoxic T cells
-Adhesion molecule that binds to MHC class I molecules; signal
transduction
CD19?
-B cells
-Signal transduction; CD21 coreceptor
CD28?
-T cells
-Receptor for costimulatory B7 molecule on antigen-presenting
cells
What are primary lymphoid organs?
where immune cells develop—bone marrow and thymus
What are secondary lymphoid organs?
where the immune response is initiated
What happens during embryogenesis and the fetal site?
blood cell formation shifts from site to site
Where does hematopoeisis begin?
the yolk sac
Where do fetal HSCs arise?
near the kidney
Mature HSCs capable of populating the hematopoietic system can be isolated from__________________
yolk sac, placenta, and fetal liver
When do HSCs ultimately populate the bone marrow?
postnatally
B lymphocytes develop in contact with the ___________cells of the bone marrow
stromal
facilitate HSC proliferation, direct migration, and stimulate differentiation
stromal cells
Where do T cells develop and mature?
develop in bone marrow, mature in thymus
The microenvironment of the ________________directs stepwise changes in thymocytes
thymic cortex and medulla
cells with immune functions
effector cells
What are the secondary lymphoid organ areas?
-lymph nodes
-spleen
-mucosa-associated lymphoid tissue (MALT)
-other diffuse and loosely organized areas
How are the secondary lymphoid organ areas connected to each other?
via the blood and lymphatic circulatory systems
What are the most highly organized secondary lymphoid organs?
lymph nodes and spleen
What are the two distinct microenvironements that B-cell and T-cell activity is separated into?
cortex and paracortex
Where are macrophages and dendritic cells found?
the innermost lymph node medulla
in which vessel does the antigen enter?
afferent
Naïve lymphocytes enter by the_________________, lymphocytes exit via the __________ vessel
- High Endothelial Venule (HEV)
-efferent
guides T cells and APCs toward activation interactions
fibroblastic reticular cell conduit (FRCC)
where does differentiation into effector cells and memory cells take place?
in follicles of secondary lymphoid organs
where do B cells undergo clonal expansion?
in germinal centers
What is the first line of defense against bloodborne
pathogens?
the spleen
red blood cells are _____________in red pulp
compartmentalized
white blood cells are __________________in white pulp
segregated
a specialized region of macrophages and B cells that border the white pulp
the marginal zone
- Important layer of defense against infection at mucosal and
epithelial layers
-organizes responses to antigens that enter mucosal tissues
mucosa-associated lymphoid tissue (MALT)
a network of follicles and lymphoid microenvironments
associated with the intestines
gut-associated lymphoid tissue (GALT)
