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level: 4. CELLS AND CELLULAR ACTIVITIES OF THE IMMUNE SYSTEM

Questions and Answers List

level questions: 4. CELLS AND CELLULAR ACTIVITIES OF THE IMMUNE SYSTEM

Question	Answer
Adaptive immune system is comprised of?	humoral and cellular systems.
It recognizes foreign antigens, directly destroys some cells, or produce antibodies as plasma cells	Lymphocytes
T-cell subsets, including NK cells, together with classic innate immune cells, contribute significantly to the development and establishment of acute and inflammatory diseases	Lymphocytes
T lymphocytes have a relatively smooth surface compared with rough pattern of the B lymphocytes.	True
are used to identify and enumerate various lymphocyte subsets, establish maturity, classify leukemias, and monitor patients on immunosuppressive therapy.	Surface markers
Cell surfaces molecules recognized by Mabs are called ___, because antibodies can be produced against them, or markers, because they identify and discriminate the different cell population	Antigens
Surface markers that identifies a particular lineage or differentiation stage with a defines structure, and can be identified with a group or cluster of Mabs, is called a member of a cluster differentiation.	LYMPHOID AND NONLYMPHOID SURFACE MEMBRANE MARKERS
The precursor of lymphocytes arise from progenitor cells of the___ and ____	yolk sac and liver.
Later in fetal development, and throughout the life cycle, the bone marrow becomes the sole provider of undifferentiated progenitor cells, which can further develop into	LYMPHOBLAST
What are the primary or central lymphoid organ	The bone marrow or the fetal liver and thymus
• Located in the mediastinum • Exercises control over the entire immune system • The characteristics of the of this organ change with aging	THYMUS
Progenitor cells that migrate to the thymus proliferate and differentiate under the influence of the humoral factor. . . ?	THYMOSIN
These lymphocyte precursors with acquired surface membrane antigens are referred to as	Thymocytes
The reticular structure of the thymus allows a significant number of lymphocytes to pass through it to become	IMMUNOCOMPETENT
Many cells die in the thymus and apparently are phagocytized.	True
Approximately ___% of the cortical cells die in the thymus before becoming mature T cells.	97
Absence or abnormal development of the thymus results in a T lymphocyte deficiency	True
It is the primary organ that produces naïve T cells for the peripheral T cell pool but production of cells declines as early as 3 months of age.	THYMUS
Source of progenitor cells • Cells can differentiate into lymphocytes and other hematopoietic cells (ex. Granulocytes, erythrocytes, megakaryocyte population) • Supports in eventual differentiation of mature T and B lymphocytes, from a common lymphoid cell progenito	BONE MARROW
• Bone marrow and the _____ may play a role in the differentiation of progenitor cells into B lymphocytes.	gut-associated lymphoid tissue (GALT)
Provide a unique microenvironment for the initiation and development of immune reponse	SECONDARY LYMPHOID ORGANS
It includes lymph nodes, spleen, GALT, skin-associated lymphoid tissue, and blood	secondary Lymphoid organs
Perifollicular and paracortical regions of the lymph nodes • Medullary cords of the lymph nodes • Periarteriolar regions of the spleen • Thoracic duct of the circulatory system	T lymphocyte or T cells populate
• Follicular and medullary (germinal centers) of the lymph nodes • Primary follicles and red pulp of the spleen • Follicular regions of GALT • Medullary cords of the lymph nodes	B lymphocyte or B cells multiply and populate
Acts as lymphoid filters in the lymphatic system respond to antigen introduced distally and routed them by afferent lymphatics	Lymph nodes
Acts as a lymphatic filter within the blood vascular tree. • Important site of antibody production in response to IV particulate antigens (bacteria) • Major organ for the clearance particles	Spleen
Includes lymphoid tissue in the intestines (Peyer’s patches) and the liver. • Features immunoglobulin A (IgA) production and involves a unique pattern of lymphocyte recirculation • Important for the development of tolerance to ingested antigens.	Gut-Associated Lymphoid Tissue
• Rich source of mature T cells • Chronic thoracic drainage can cause T cell depletion and has been used as a method of immunosuppression	Thoracic Duct
• Includes lymphoid tissue in the lower respiratory tract and hilar lymph node • Mainly associated with IgA production in response to inhaled antigens	Bronchus-Associated Lymphoid Tissue
• Antigens introduced through the skin are presented by epidermal Langerhans cells	Skin-Associated Lymphoid Tissue
• Important lymphoid organ and immunologic effector tissue • Circulating blood has enough mature T cells to produce a graft-versus-host reaction	Blood
Mature T lymphocytes survive for several months or years, whereas the average life span of B lymphocytes is only a few dayst	true
it enables lymphocyte to come into contact with processed foreign antigens and disseminate antigen-sensitized memory cells through out the lymphoid system	LYMPHOCYTE RECIRCULATION
mature in the thymus gland, survive for several months or years.	Mature T lymphocytes
can only survive for a few days, mature in the bone marrow.	B lymphocytes
CIRCULATION OF LYMPHOCYTES	venule- node- circulating blood
Expansion of lymphocytes, a hallmark of vertebrate adaptive immunity. A small number of precursor cells that recognize a specific antigen proliferate into expanded clones, differentiate and acquire various effector and memory phenotypes, which promote effective immune responses.	Clonal Expansion
-clones able to recognize and react to foreign antigens.	Positive selection
-(purging) of clones able to interact with self-antigens in a damaging way.	Negative selection
Are cells that have not encountered their specific antigen. ● These cells do express high-molecular-weight variants of leukocyte common antigen.	Virgin or Naïve lymphocytes
Are populations of long-lived T or B cells that have been stimulated by antigen. They can make a quick response to a previously encountered antigen. carry surface IgG as their antigen receptor; memory T cells express the CD45RO variant of the leukocyte common antigen and increased levels of cell-adhesion molecules (CAMs), chemical mediators involved in inflammatory processes throughout the body.	Memory cells
Phases of an adaptive immune response	the first three are the recognition of antigen, activation of lymphocytes, and elimination of antigen (effector phase).
● Most lymphocytes found in the circulating blood are T cells derived from bone marrow progenitor cells that mature in the thymus gland. These cells are responsible for cellular immune responses and are involved in the regulation of antibody reactions in conjunction with B lymphocytes.	True