Immune/Lymphoid Systen PT 1 Flashcards
____ develop from activated T cells to provide a ‘rapid reaction force’ for a
subsequent encounter with the same antigen.
Memory T cells
Medullary sinuses—broad,
lymphatic channels in inner, less
___
cellular medulla
4 Functions of Lymph Nodes:
Non-specific filtering of particulate matter & microorganisms
from lymph
* Interaction of circulating lymphocytes with Ag in lymph
* Aggregation, activation, & proliferation of B-cells with
subsequent Ab production
* Aggregation & proliferation of T-cells & induction of cytotoxic
immunity
(Lymph node morphology) Blood vessels enter & leave
lymph nodes at _____
hilus
As ____ mature, they express:
* Ag specific t-cell receptors
* CD (cluster of differentiation) surface markers
* Class I & II HLA (human leukocyte Ag) surface markers
t-cells
First line of
defense in skin and mucous membranes are
protected by a variety of antibacterial substances
including defensins, short antimicrobial peptides
that are found in surface mucus, and the enzyme
lysozyme, which is secreted in tears and saliva.
Protective surface Mechanisms
Cytotoxic T cells (TC cells). These lymphocytes are able to kill virus-infected and
some cancer cells. They require _____ to become activated and
proliferate to form clones.
interaction with TH cells
Immune System 3 lines of defense:
1) Protective surface mechanisms
2) Innate immune system
3) Adaptive immune system
Lymph drains from ___
via single, efferent lymph vessel
hilus of node
Malignant tumors of immune system referred to as lymphomas
when they involve solid organs & _____ when they involve
blood
leukemias
(cells in lymph nodes)—fibroblasts & reticular cells (fibroblast-like cells
with phagocytic capability); part of formation of CT skeleton of Lymph nodes
stromal cells (with extracellular prod forms skeleton)
(Lymph node morphology) Extensions of cortical tissue
into medulla called ____
medullary
cords
Phagocytosis and killing of pathogenic organisms
Secretion of cytokines and extracellular antimicrobial
molecules, including neutrophil extracellular traps
(NETs) and pattern recognition molecules (PRMs)
Neutrophils
Malignant tumors of immune system referred to as _____
when they involve solid organs & leukemias when they involve
blood
lymphomas
(Lymph node Ultrastructure) Proliferation of lymphocytes => lnn
enlargement & ____
“swollen glands”
IgG, IgA, IgD, IgE, IgM are synthesized by
plasma cells
(Lymph node morphology) Grossly, lymph nodes have
dense, outer, cellular ___
(contains B-cells, T-cells, &
plasma cells) & less _____
dense cellular cortex, less cellular inner medulla
Lymph Vessels: Assist circulation of
lymphocytes,
concentrate Ag for
elimination within
___
lymph nodes
(Lymph node Ultrastructure) Darker staining rim surrounding
germinal center called _____—region of Ag
presentation
mantleor
marginal zone
_____ modifies some of the innate response
(opsonisation & complement cascade).
Adaptive response
Medullary sinuses—broad,
lymphatic channels in inner, less
cellular medulla; contain
lymphocytes, plasma cells, Mφ;
converge on ____
hilus
(cells in lymph nodes) ____ cell —Ag presenting cells (Mφ, b- & t-cells;
originate in bone marrow)
immune accessory cell
Thymic blood vessels also surrounded
by connective tissue sheath called
______
blood-thymus barrier
—space beneath
capsule where numerous
afferent lymph vessels drain
into
Cortical or subcapsular
sinus
Secrete various hormones
(thymotaxin, thymosin, &
thymopoietin)—attract, regulate
& promote t-cell proliferation & differentiation into Tc, Ts & Th
cells
Thymus
Activated B cells undergo
mitosis and divide into
clones that can make
more cells to produce
antibodies to the same
antigens.
* Also make ____ cells
memory B
cells.
___ are not
open spaces like blood
sinuses—filled with reticular
fibers & M φ processes
Lymphatic sinuses
(Thymus) Because t-cells _____,
no afferent lymph vessels to thymus,
only efferent, for lymph drainage
are not fully differentiated
Adaptive immune system: depends on ____
Lymphocytes
Thymus: Undergoes fatty infiltration & lymphatic
depletion (______)
thymic involution
is secreted in tears and saliva.
the enzyme
lysozyme
Name organs of the immune system
lymph nodes, lymph vessels, spleen, peyer’s patch, lymph node, lymphatic vessels, bone marrow, appendix, thymus, tonsils and adenoids
—broad,
lymphatic channels in inner, less
cellular medulla; contain
lymphocytes, plasma cells, Mφ;
converge on hilus
Medullary sinuses
Lymphatic drainage to ___
lymph nodes important in
metastasis of tumor cells
regional
Describe the arrangement of Lymph Nodes
Arranged in chains or clusters along vessels of lymphatic
origin
(e.g., submandibular, cervical, axillary, femoral, popliteal)
Thymus: Has thin capsule of
____
connective tissue
dense, irregular CT
Lymphocytes: T cell receptors antigen binding also depends on
shape and charge but it must also bind to _____
major
histocompatibility complex (MHC
Lymphatic sinuses are not
open spaces like blood
sinuses—filled with ____ and ___
reticular
fibers & M φ processes
B cells mature in bone
marrow and develop into
____
plasma cells.
signaling proteins that guide the movement of cells, such as WBCs, to the areas of inflammation or infection. They also play a role in the development of WBCs in the bone marrow
Chemokines
Detail of Hassall’s corpuscle, with concentric layers of keratinizing epithelial cells.
Although the significance of the corpuscles is uncertain, they are apparently formed
from the ____
epithelioid stromal cells
(adaptive immunue system) Lymphocyte responsible for humoral response
B cell
(Innate Immune System) Acute inflammation is characterized by vascular changes
including dilation, enhanced permeability of capillaries and
increased blood flow, resulting in the production of a _____, thus bringing the proteins and cells
required for early defense to the site of infection.
fibrin-rich
inflammatory exudate
– provides a rapid reaction to a
pathogen. There is the same magnitude of reaction with each
encounter
Innate immune system
(Lymph node morphology) Outer, fibrous capsule of ____connective tissue
dense,
irregular CT
Lymphocytes: Activated when antigen binds to their ____
surface
receptor
blood-thymus barrier: Consists of epithelioreticular cells,
reticular fibers, fibroblasts, Mφ, plasma
cells, surrounds endothelium &
_____ of BV
basement membrane of blood vessels
T/F: Lymphatic Vessels have valves
true
Primary lymphoid tissue–Mature b- & t-cells secondarily migrate to all other lymphoid
tissue, referred to as ___
Secondary lymphoid tissue
Innate Immune System: ______ is characterized by vascular changes
including dilation, enhanced permeability of capillaries and
increased blood flow, resulting in the production of a fibrin-rich
inflammatory exudate, thus bringing the proteins and cells
required for early defense to the site of infection.
Acute inflammation
(Thymus) ______: – Immature T-Lymphocytes
– Epithelial Cells (Nurse Cells) – secrete thymic
hormones
– Some Macrophages
Outer Cortex
Innate Immune System: Acute inflammation is characterized by vascular changes
including ____, ___, ______, resulting in the production of a fibrin-rich
inflammatory exudate, thus bringing the proteins and cells
required for early defense to the site of infection.
dilation, enhanced permeability of capillaries and
increased blood flow,
post-capillary
venules (= high endothelial
venules) —lined by cuboidal to
columnar endothelium; located
in deep, inner cortex of node at
____
corticomedullary junction, or
paracortical zone
–Production of mature, immunocompetent Th & Tc cells
* Clonal proliferation of Tc cells
* Clonal deletion of self-Ab’s
Development of immunologic self-tolerance
Failure of clonal deletion may => autoimmune diseases
* Secretion of hormones regulating t-cell development &
maturation
(Functions of WHAT)
Thymus
diapedesis—
facilitated by _____ present on
both endothelial cells &
lymphocytes
complementary
adhesion molecules
The paler thymic medulla shows some bright
pink Hassall’s corpuscles. They are __ for thymus
diagnostic
features
short antimicrobial peptides
that are found in surface mucus
defensins
Lymphatic Vessels: Assist circulation of
_____,
concentrate Ag for
elimination within
lymph nodes
lymphocytes
—lined by cuboidal to
columnar endothelium; located
in deep, inner cortex of node at
corticomedullary junction, or
paracortical zone
post-capillary
venules (= high endothelial
venules)
____ detects, tags, and
eliminates microbial intruders, and helps the
body heal after an injury or infection. It also
helps to clean up damaged cells.
The complement system
plasma cells: Activated ____ undergo
mitosis and divide into
clones that can make
more cells to produce
antibodies to the same
antigens.
B cells
Thymus has highly
cellular cortex
packed with
______
lymphocytes,
mostly t-cells & M φ
(Morphology of Lymphoid Tissue) —lymphoid tissue where b- & t-cells
acquire surface receptors
(bone marrow with b-cells & thymus with t-cells)
Primary lymphoid tissue
(cells in lymph nodes)—1’ found in germinal centers; possess
numerous phagocytic vesicles
Tingible body Mφ
(Lymph node morphology) Separated by broad lymphatic
channels, ____
medullary sinuses
Memory T cells: This is the basis of persisting immunity
after infection with some organisms and also the basis of ___
vaccination.
(Thymus) Failure of clonal deletion may lead to:
autoimmune diseases
Phagocytosis and killing of pathogenic organisms
Secretion of cytokines and extracellular antimicrobial
molecules, including neutrophil extracellular traps
(NETs) and pattern recognition molecules (PRMs)
macrophages
These T lymphocytes ‘help’ other cells to perform their
effector functions by secreting a variety of mediators; thus provide assistance to B
cells, cytotoxic T cells and macrophages.
T helper cells (TH cells).
Thymus: ____ absent;
limited local clonal
expansion of t-cells
2’ follicles
Constantly patrol the body, circulating in blood,
lymph and extracellular fluid, pausing in organized
lymphoid tissue.
lymphocytes
Provide a route
which allows cells &
large molecules in
extracellular space to
re-enter bloodstream
Lymphatic Vessels:
(Lymph node Ultrastructure) Within cortex are densely packed,
highly cellular ____
(= lymphatic nodules, 1’ follicles)
lymphoid follicles
Innate Immune System: Consists of cells (WBCs), proteins & peptides that circulate in
the blood. Initial innate response causes _____
inflammation
(cells in lymph nodes) lymphoid cell—lymphocytes of all types, derived from bone
marrow; enter node via ____
bloodstream
Opsonises organisms to facilitate phagocytosis
Chemoattractant for various cells
Membrane attack complex (MAC) kills cells by
puncturing plasma membrane
Complement
B & T cells migrate across walls of
specialized ____ (= high endothelial
venules)
post-capillary
venules
—encapsulated aggregates of lymphocytes &
lymphoid tissue, distributed throughout body
Lymph nodes
(Adaptive response) It is also controlled by the innate response & requires ____
antigen-
representing cells
(cells in lymph nodes)—M φ at periphery of germinal
centers; Ag-presenting cells
follicular dendritic cells
Degenerates at puberty, vestigial in
adults
Thymus
(Lymph node Ultrastructure) Lymphocytess respond to Ag by ↑
Ab production via ___
clonal expansion
Lymph eventually returns to bloodstream
via ___ or ___
thoracic duct or R lymphatic
duct
Thymus: Similar in appearance to
lnn, but lacks lymphoid
follicles; medulla lacks
___ and ____
medullary cords &
sinuses
T helper cells (TH cells). These T lymphocytes ‘help’ other cells to perform their
effector functions by secreting a variety of ____. TH cells thus provide ‘help’ to B
cells, cytotoxic T cells and macrophages.
mediators
forms continuous
antigenic barrier; isolates thymus from
immune system
blood-thymus barrier
– has the ability to learn
so that second/subsequent response elicits a
greater, more specific and faster response.
Adaptive immune system
(cells in lymph nodes) Stromal cells & extracellular products (collagen & reticular
fibers), form _____ of lymph nodes
connective tissue skeleton
Immature T cells migrate from bone marrow to
____ where they mature.
thymus
(adaptive immunue system) Lymphocyte responsible for cellular response
T cell
Thymus: Similar in appearance to
lnn, but lacks ____; medulla lacks
medullary cords &
sinuses
lymphoid
follicles
Lymphatic Vessels: Network of blind-
ended vessels in
_____
connective tissue
(Lymph node morphology) Interspersed throughout cortex
& medulla are very thin,
___
collagenous trabeculae
T-Lymphocytes can develop into:
T helper cells, cytotoxic cells, regulatory T-cells, memory T cells
These cells suppress immune responsiveness to self-
antigens (autoimmunity) and switch off the response when antigen is removed.
Regulatory T cells (TREG).
B- & T-cells leave bloodstream
& enter node via:
diapedesis
(Innate Immune System) Many of the cells and signaling molecules of the innate immune
system are vital to the functioning of the ____
adaptive immune
system.
____ are eosinophilic, lamellated
structures within both medulla
& cortex, represent degenerate
reticular & epithelial nurse cells
Thymic or Hassall’s corpuscles
Lymphocytes: Huge variety of B cell receptors; binding depends on
___ and ____
shape and electrical charge.
(Thymus) Inner surface of capsule has continuous
epithelium to ____
isolate thymus
Sinuses in ____—
cortical sinuses, trabecular
sinuses, or peritrabecular sinuses
Sinuses in outer cortex
Protective surface Mechanisms: First line of
defense in skin and mucous membranes are
protected by ____ and ___
defensins, (found in surface mucus) and the enzyme
lysozyme (secreted in tears and saliva)
(Lymph Node) Endothelium of sinus on
side adjacent to capsule
______, but ____
on side adjacent to parenchyma
continuous (prevents
leakage); discontinuous
Slender ____ or ____ divide
thymus into lobules
interlobular septa
or trabeculae
These lymphocytes are able to kill virus-infected and
some cancer cells. They require interaction with TH cells to become activated and
proliferate to form clones.
Cytotoxic T cells (TC cells).
Immune System: All ____ is subject to constant invasion by a variety
of pathogens
tissue
Thymus: Lobular, lymphatic organ
located in ____
mediastinum
(Thymus) _____: Epithelia Cells
– Mature T-Lymphocytes
– Thymic Corpuscles (Hassall Corpuscles)
* Circular aggregations of aged, degenerated Nurse Cells
Inner Medulla
(Morphology of Lymphoid Tissue) —-
located throughout body, associated with mucous
membranes
* Both contain large #’s of lymphocytes
* Common in respiratory & digestive tracts as MALT
Diffuse
Protective surface Mechanisms: First line of
defense in skin and mucous membranes are
protected by ____
including defensins, short antimicrobial peptides
that are found in surface mucus, and the enzyme
lysozyme, which is secreted in tears and saliva.
a variety of antibacterial substances
(cells in lymph nodes) _____ cell—lymphocytes of all types, derived from bone
marrow; enter node via bloodstream
lymphoid cell
—epithelial cells
within thymus, provide nurse
function & structural suppor
Nurse cells
Thymus: Less cellular, ____
contains mostly b-cells, plasma
cells & M φ
central medulla
Recognize and kill virus-infected and cancerous cells
Natural Killer (NK) cells
Plasma cells: Synthesize large amounts
of ____
antibodies
(immunoglobulins)
(Lymph node Ultrastructure) May contain paler, less dense
_____ (if present, follicle
then referred to as 2’ follicle),
indicate node is responding to Ag
germinal centers
Phagocytosis and killing of pathogenic organisms
Secretion of cytokines and extracellular antimicrobial
molecules, including neutrophil extracellular traps
(NETs) and pattern recognition molecules (PRMs)
eosinophils
Non-specific filtering of particulate matter & microorganisms
from lymph
* Interaction of circulating lymphocytes with Ag in lymph
* Aggregation, activation, & proliferation of B-cells with
subsequent Ab production
* Aggregation & proliferation of T-cells & induction of cytotoxic
immunity
(These are the functions of WHAT?)
Lymph Nodes
(Lymph node Ultrastructure) Sites of b-cell proliferation, (2’
hemopoiesis), contain
_____, _____, and ____
lymphoblasts, Mφ, & immature b- &
t-cells
(Morphology of Lymphoid Tissue)—organized into discreet structures or organs (e.g., lymph
nodes, spleen, thymus, tonsil
Dense
