Lecture 8-10 lymphatics Flashcards
1
Q
___ comprises the vessels and organs that allow the immune system to work
A
lymphatic system
2
Q
some components of the lymphatic system are
A
thymus, lymph nodes and spleen
3
Q
lymphatic system maintains ___
A
functional immunity
4
Q
Primary lymphatic organs
A
bone marrow
thymus
5
Q
Secondary lymphatic system
A
Lymph nodes
spleen
mucosa associated lymphoid tissue (MALT)
6
Q
Tertiary Lymphatics
A
small lymphatics organs that show up during some diseases and preform immune functions
7
Q
Adult cells of lymphatic system
A
effector B cells
effector T cells
8
Q
another name for effector B cells
A
plasma cells
9
Q
where are lymphatic cells generated and “educated”
A
primary lymphoid organs
10
Q
where are lymphatic cells maintained and activated
A
secondary lymphoid organs
11
Q
How do lymphatic cells survey an animal
A
Lymphocyte recirculation
12
Q
steps of innate immune response
A
first line of defense
rapid
mediated by non-specific effector cells (macrophages and neutrophils)
13
Q
steps of adaptive immune response
A
later, long lived, memory cells
mediated by T-cells and B cells (cellular-(T-cells) and humoral (B-Cells))
highly specific (antigen recognition)
requires initial innate immune response
14
Q
how does macrophages and neutrophils destroy pathogens
A
“eats them”
phagocytosis
innate immune response
15
Q
soluble proteins made by one cell that affect the function of another
A
cytokines
16
Q
chemotactic cytokines
A
chemokines
17
Q
explain how cytokines work
A
Macrophage eats pathogen, this triggers the release of cytokines, which will trigger dilation of local small blood vessels
adhesion molecules are expressed on inside of blood vessels.
these, adhesion molecules, attract leukocytes
leukocytes are taken out of the blood vessel and carried to the original infection because they are attracted by “chemokines”
18
Q
___ attracts more macrophages/neutrophils to help in the inflammatory response
A
chemokines
19
Q
what cells are requires for the initiating of adaptive immune response
A
dendritic cells
20
Q
explain how dendritic cells work
A
capture some bacteria
breaks it up and then takes part of antigen and “presents” it on the dendritic cells surface
Then move to nearest lymphatic vessel and then “drains” into the nearest lymphatic organ (lymph node)
this activates T- Lymphocytes
21
Q
T cells and B cells have ___ on their surface
A
monoclonal antigen receptors
22
Q
small piece of pathogen that is recognized by T and B cell antigen receptors
A
antigen
23
Q
Each B cell can identify many types of antigens
True or False
A
False
1 b cell=1 antigen
very specific
24
Q
Antigen presenting cells are also called ___
A
dendritic cells
25
Where do T-cells develop
in the Thymus
26
T cells can turn into
T-helper cells (CD4)
T-Cytotoxic (CD8)
(single positive SP)
27
double positive T cells
precursor T cells that have CD4 and CD8
28
T-helper cells
CD4
producing cytokines and other soluble mediators that **HELP** other cells of the immune response including macrophages, eosinophils and B cells
29
T cytotoxic
CD8
finds and kills infected cells
30
How does T cell “see” antigen
antigen is expressed on surface of dendritic cell
## Footnote
T cell receptor (TCR) sees and binds to this peptide antigen
antigen is presented on specific **MHC proteins**
31
MHC are found in what
dendritic cells
32
explain how pathogen gets expressed by dendritic cells
dentrictic cell eats pathogen
lysomes breaks down pathogen into antigen
MCH proteins are attached to antigen
this is then expressed onto membrane and is “seen” by the T cell receptor of a T cell
33
steps of T cell
recognition phase
activation phase (clonal expansion)
effector phase
34
parts of effector phase of T cells
macrophage activation
B cell activation/antibody production
inflammation
memory T cells
T cell mediated Cytolysis
35
B cells develop in the
bone marrow
Bursa of Fabricius (in chickens)
36
what do B cells do
make antibodies
make memory cells (respond to second infection)
antigen receptor on surface is the antibody that Bcells will produce
BCR(antibody) only recognize 1 antigen (directly- free floating antigens)
37
B cells turn into
activated -clonal expassion
memory cell or plasma cell
38
plasma cells are
B cells that have differentiated into plasma cells that have increased cytoplasm and increased ER that is used to make antibodies
antibody production
39
what do antibodies do?
neutralization (block viral binding)
agglutination (clumps together)
precipitation of dissolved antigens
these steps will be identified by macrophages and be eaten
activation of complement system
leads to
cell lysis
40
antibodies will activate the complement system which leads to
cell lysis
41
adaptive immunity is mediated by
B cells and T cells
42
activated B cells make
antibodies (Humoral)
43
activated T cells make
cytokines/kills cells
| (cellular)
44
unique antigen receptors
B cell receptors
T cell receptors
45
B cells recognize
“free" antigens
46
T cells recoginize
processed and MHC-presents antigen
47
Cytotoxic T cells
CD8
kill infected cells
48
Helper T cells
CD4
help shape the specific immune response
49
primary lymphoid organs
where B cells and T cells develop
50
B cells come from ___ and develop in \_\_\_
Fetal liver
bone marrow (pluripotent hematopoietic stem cells)
bone marrow
51
T cells come from ___ and mature in \_\_\_\_
fetal liver
bone marrow (pluripotent hematopoietic stem cells)
Thymus
52
Thymus
bilobed, mediastinal location anterior to the heart
stroma (support structure) is epithelial cells
lobes subdivided into lobules and are separated by trabeculae
53
the stroma of the thymus are
epithelial cells
54
the lobules of the thymus are separated by
trabeculae
55
in mature animals the thymus
involutes and shrinks- not completely
humans early 20s
56
each lobule of the thymus are broken into two regions:
cortex -dark stained
medulla- lighter
57
thymus is contained in \_\_\_
a capsule
58
what is number 5
trabeculae that separate each lobule of the thymus
59
what is 3
medulla (inner lighter area) of the thymus
60
What is 2
Cortex (outer region -darker)
61
What is 4
capsule of the thymus, which covers the entire thymus
62
structure in thymus that is surrounded by cell death
hassal's corpuscle
thymic corpuscle
found in medulla of lobule of thymus
63
developing T cells are called ___ and are found in \_\_\_\_
thymocytes (double negative (DN) cells CD4- CD8-)
found in cortex (outer darker region of thymus)
64
\_\_\_ epithelial cells are found in the cortex of the thymus
cortical
65
\_\_\_ epithelial cells are found in the medulla of the thymus
medullary
66
part of the thymus that are made from mesenchymal cells
capsule, trabeculae/septae containing blood vessels
67
\_\_\_ are found in the medulla of the thymus
hassal's corpuscles
dendritics cells
macrophages
68
what might Hassal's Corpuscles do
found in medulla of the thymus
keratinized epithelium, necrotic, possibly site of cell destruction??
69
Thymocytes learn how to identify self from non self by \_\_\_
interacting
positive and negative selection of mature T cells
70
errors in self recognition of T cells are
autoimmune diseases
71
subcapsular cortex of thymus
immature T cell precursors (CD4-CD8- double negative cells) interact with cortical EC
begin to differentiate
T Cell receptor (TCR) proteins made and inserted into membrane (CD3+)
Cells obtain surface expression of CD4 and CD8 (double positive (DP) cells)
72
mid cortex of thymus
TCR (T cell receptors) bind to self MHC on cortial epithelial cells (self recognition test)
thymocytes that recognize MHC get survival signal
Thymocytes that fail die or get eaten
**Positive Selection**
surviving thymocytes differentiate into CD4+ and CD8+ (single positive cells)
73
TCR bind to self MHC on cortical epithelial cells
self recognition test
mid cortex of thymus
how to make a T Cell
74
cell death
apoptosis
75
steps of T cell development in the thymus
1. double negative to double positive thymocytes
2. positive selection (single positive cells)
3. negative selection (self tolerance)
4. exit
76
if a thymocytes can not see a MHC the cell will
die
happens in mid-cortex
77
negative selection of T cell development
step 3 happens in the corticomedullary junction
self tolerance test
dendritic cells and macrophages present common self antigens (parts of every part of the body)
self reactive T cells MHC die and get eaten (T cells see itself this is bad should not see itself as antigen)
**NEGATIVE SELECTION**
78
Exit phase of T cell development
in the medulla of the thymus
mature T cells leave bis postcapillary venules to reach circulation
migrate to secondary lymph nodes to “meet” antigen
only around 2-5% make it to the end
79
what % of thymocyes become mature T cells
2-5%
50,000,000 in and 1,000,000 out every day
80
T cell precursors migrate from the ___ to the \_\_\_
bone marrow
thymus
81
Thymus is a mesh of ___ and ___ epithelial cells
cortical
medullary
82
Thymocytes differentiate and become ___ and \_\_\_
T Helper (CD4)
T Cytoxic (CD)
83
Two tests that thymocytes undergo while in the thymus
positive (not self) selection
negative (self) selection
84
B cell development happens in the \_\_\_, in neonatal pigs, sheep and cow, B cells can devlop in the ___ of the gut
bone marrow
Peyer's Patches
85
Describe B Cell development
happens in bone marrow (mammals)
B cells precursors interact with stromal cells that provide signals and growth factors promoting immunoglobin gene (antibody) rearrangment
self-reacting B cells die (negative selection) and surviving immature cells migrate via circulation to spleen and peripheral lymph nodes to fully mature (antibody class switch)
86
B cells in birds
bursa of fabricius
round sac like diverticulum in the cloaca
many folds that have lymphoid follicles lined with pseudostratified columnar epithelium
cortex and medulla
anibody gene rearrangment/ conversion occurs in the cortex and negative selection leads to loss of self reactive B cells (lighter medulla)
87
where and what is the bursa of fabricius
in birds need cloaca
where B cells develop
88
Bursa of fabricius
NAME THE STRUCTURES
89
B cells develop in the ___ of mammals and in some neonates in the \_\_\_\_
bone marrow
peyer's patch
90
B cells develop in the ___ in birds
bursa of fabricius
91
self reactive B cells are \_\_\_
deleted, killed eaten
92
examples of secondary lymphoid organs
lymph nodes (periphery)
spleen (blood)
Mucosa-associated lymphoid tissue (MALT)
Hemal Nodes (Ruminants)
93
similarites of secondary lymphoid organs
discreet organs
segregated areas (zones)
B Cells in follicles
Germinal centers form in follicles when B cells activate/proliferate
T-cell area contains APCs(i.e. DCs)
lymphocytes (most) enter via blood
94
differences in secondary lymphoid organs
architecture/structural components
mechanism of lymphocytes entry from blood
mechanism of antigen entry (from blood, lymphatics, via epithelium)
95
secondary lymphoid organs are divided into two spaces
diffuse (T cells)
nodal (B Cells)
96
T cells and ___ go to the same area of secondary lymphoid organs
dendritic cells (APCs)
97
diffuse lymphatic tissue is where ___ go in secondary lymphoid organs
T cells and APCs (dendritic cells)
98
nodular(follicles) areas of secondary lymphoid organs is where ___ go
B cells
99
What do lymph nodes do
strategically placed to collect antigen from **Tissues** to be presented to lymphocytes
Antigens enter via **lymphatic vessels** (dendritic cells/fluid from tissues)
Most lymphocytes enter from **blood**-some T cells enter via lymphatics
fluid homeostatis
100
Do avians have lymph nodes
NO
diffuse lymphatic tissue
lymphatic follicles/nodules
101
explain lymphatic vessels
carry “lymph” from peripheral tissue to lymph nodes
blind ended one way vessels that begin in the interstitial space in tissues
102
what is lymph
fluid inside lymphatic system that contains fluid, white blood cells (some T cells and dendritic cells) and antigens (free floating)
lymph comes from everywhere and drains through one way valves into lymph nodes
103
lymphatic circulation
lymphatic capillary, lymphatic vessel, lymph node, lymphatic vessel, thoracic duct, subclavian vein….blood circulation
104
describe lymphatic vessels
thin layer of endothelial cells
slow moving, not pumped
moved by **negative** intraluminal hydrostatic **pressure** that draws in fluid from the interstitial space of tissues (also SMC contractions/chemotaxis)
105
Describe Lymph nodes
soft, pale tan oval- kidney shaped
buried in fat
swell when immune response ongoing
encased in a fibrous capsule with an internal framework of fibrous trabeculae/septae
interior is a mesh of reticular cells (stroma) and fibers containing highly segregated areas
106
identify
lymph node
107
T cell and dendritic cell areas of lymph node
paracortex (out part of lymph node) outside of follicles
3b
108
What cells are found in the follicle of the lymph node
B cells
109
antigens in dendritic cells (DCs) and fluid and some lymphcytes (\<5%) enter via \_\_\_
afferent lymphatics
110
Afferent lymphatic penetrate the capsule of the lymph node and drain into the
subcapsular sinus
111
Lymph percolates through ___ to ___ then exits via ___ to throacic duct and back to blood circulation
paratrabecular sinuses(conduits) (cords)
medullary sinus
efferent lymphatics
112
\_\_\_ and ___ in sinuses of lymph node ___ antigen in lymph fuild
macrophages and DCs
phagocytose (eat)
113
lymph in \_\_\_\_, lymph out \_\_\_
antigen rich
lymphocyte-rich
114
paracortex of the lymph node has
T cells and dendritic cells
115
B cell area of a lymphnode \_\_\_,has an inner area called ___ and outer area called \_\_\_
nodule
germinal center (primary, secondary, senescent)
corona
116
FRCs
Fibroblastic Peticular Cells
attract T and DC cells
117
FDCs
Follicular Dendritic cells
attract B cells
118
FRCs and FDCs direct “zoning” by expressing
chemokines
Fibroblastic Reticular Cells -CCL19,CCL21
T cells and DC cells
Follicular Dendritic Cells- CXCL13
B Cells
119
Fibroblastic Reticular Cells -
chemokine CCL19,CCL21
Chemokitic for T cells and Dendritic cells
(will bring T cells and DC together)
120
Follicular Dendritic Cells
chemokine CXCL13
B cells are attracted to CXCL13
121
Follicular Dendritic Cells are found in \_\_\_
follicles/nodules in lymph nodes (spleen and MALT)
122
Explain Follicular Dendritic Cells
found in germinal centers(light zones) of the follicles/nodule of lymph nodes
Can see naked antigen or antibody with antigen attached and will capture it
Will release cytokine CXCL13 which will attract Bcell
BCell with the correct binding site will attach and will become
Plasma cell that makes antibodies
or
Memory B cell
123
specialized post capillary venules in the paracortex through which lymphocytes (95%) and macrophages enter the lymph nodes
high endothelial venules
124
why are HEV named that
High endothelial venules
the unusual plump and cuboidal morphology of the endothelial cells
125
\_\_ express lymphocyte-specific adhesion molecules
HEC
126
After leaving via HEV, lymphocytes segregate into zones by following \_\_\_
chemokine gradients
127
HEV are in the ___ of the lymph node
cortex
128
lymph node what is the arrow?
HEV
high endothelial venules
129
Medulla of the lymph node
inner part of lymph node (macrophages and plasma cells)
medullary sinus
medullary cords
130
medullary sinus is lyphatic vessels separated by
medullary cords (reticular fibers)
131
medullary sinus contains ___ that phagocytose debris/ microorganisms
macrophages
132
Medullary cords contain ___ and __ that have migrated from germinal centers
macrophages
plasma cells
133
Plasma cells make antibodies that exit the lymph node via ___ and enter circulation
efferent lymphatics
134
Medullary sinus has \_\_\_\_
Medullary cord has \_\_\_\_
macrophages and reticular cells
packed with plasma cells
135
The spleen
removed antigen directly from the blood to encounter B and T cells
removes and destroys aging red cells and other hematopoietic cells
during fetal development spleen can make blood cells, declines in adults but can reoccur in extreme anemia - extramedullary haematopoesis
136
\_\_\_ antigen and __ lymphocyte enter from the blood in the spleen
ALL and ALL
137
during anemia or systemic infections, spleen can make lymphoid or red blood cells this is called
extramedullary haematopoesis
138
parts of the spleen
white pulp- lymphocyte come here (antigen, T cells, B cells- where antigen recognition happens)
red pulp- where red blood cells go
sunuses
arterioles- found in
139
red pulp of spleen
less cells/ red cell rich
site of. red cell destruction
network of splenic sinusoids
140
white pulp of spleen
dense structures
contains lymphocytes
141
PALS of spleen
periarteriolar lymphoid sheath
contain T cell Zone
area around the central arteriole
142
Follicle of Spleen
Contains B cells (5% T helper)
143
marginal zone of spleen
border of Red pulp and white pulp
contains M phages, DCs and B cells
144
spleen
145
blood circulation in the spleen
all antigens and lymphocytes enter from the blood
supplied only by arterial blood vis the trabecular artery
blood flows through central arteriole, the marginal sinus, arterioles, splenic sinuses, venules then to trabecular vein **(closed circulation)**
Lymphocytes and antigen also enter form terminal arterioles (**Open circulation)** into the red pulp
some arterioles/capillaries are sheathed in reticular fibers/macrophages (**ellipsoids**)
146
marginal zone
lymphocytes migrate from blood to PALS (T cells) or the follicles (B cells)- driven by chemokines
antigens are eaten by macrophages, DCs and Marginal zone B cells in the “marginal zone”
macrophages, DCs and Marginal zone B cells carry antigen to T cells in PALS/Follicle that become activated and “help” B cells
antigen “presented” by **Follicular Dendritic Cells** to B cells in Follicles
147
in the marginal zone of the spleen what eats antigens
macrophages, DCs and Marginal zone B cells
148
MALT
mucosa-associated lymphoid tissue
collect antigen in mucosal surface:
respiratory tract
skin
intestinal tract
urogenital tract
mammary glands
149
GALT
gut associated lymphoid tissue
150
NALT
nasal associated lymphoid tissue
151
MALT
unorganized
T cells (little dots) are scattered throughout the surface epithelial laters (inter-epithelial lymphocytes)
**diffuse lymphatic tissue**- not encapsulated
152
organized MALT
tonsils in oral pharynx (lingual, tubal,palatine)
adenoids in nasal cavity
appendix in gut
Peyer's patch in gut
153
crypts are found in the palatine tonsil of \_\_\_
horses
no crypts in carnivores
154
Horse Palatine Tonsil
155
Where are peyer's patches located
lower portion of the small intestine (distal jejunum and throughout the ileum)
156
in pigs and ruminants what are the two types of peyer's patches
jejunal patches: remain throughout life to protect intestine
ileocecal patches: early B cell development then regress (at 6 months)
157
what is the largest collection of mucosal lymphoid tissue
peyer's patch
158
Dog Peyers Patch
159
peyers patch provides ___ for gut
immune protection
160
M Cells
multifold cells
help peyer's patches in gut
highly specialized epithelial cells
sample antigens as they pass by (engulf antigens)
then bring the antigens into the prior patch
161
how does salmonella get into body
uses M cells (multifold cells) to get into body
found in gut wall
162
antigen in lumen is collected in specialized epithelial cells names Multifold cells that are within an area of \_\_\_\_
FAEs
follicle-associated epithelial cells
163
antigens are brought from the gut, through the M cells, into the peyers patch by
transcytose
164
lymphocytes enter peyers patch via
High Endothelial Venules (HEV) located in the T cell zones
165
lymphocytes leave the peyers patch vis the
blood circulation
166
Dendritic cells exit the peyers patch by
draining lymphatics- will migrate to mesenteric lymph nodes
