Lymphatic System Flashcards
(105 cards)
1
Q
What are the three main functions of the lymph system
A
- Defense 2. Maintenance of body fluids 3. extramedullary hematopoiesis.
2
Q
What are the encapsulated components of the lymph system
A
Lymph nodes thymus, spleen
3
Q
Does the lymph system use pumps to move lymph through the body
A
No it is passive, uses valves to control backflow
4
Q
In what does lymph flow away from the tissues
A
In lymphatic capillaries
5
Q
What are the two lymphatic ducts? Which is bigged
A
Thoracic duct bigger and right lymphatic duct smaller
6
Q
Where does he lymph in the right lymphatic duct come from
A
Collects lymph from the upper right quadrant of the body
7
Q
Where does he lymph in the thoracic duct come from? where is it
A
Begins in the abdomen and ascends through the thorax/neck collects lymph from the remainder of the body
8
Q
Where do lymphatic ducts empty
A
into the great veins of the neck
9
Q
Compare dot blood vessel do lymphatic vessel have thinner or thicker walls? more valves?
A
thinner walls, more valves
10
Q
Is the basal lamina of lymphatic vessels there?
A
Yes it is incomplete
11
Q
Are lymphatic vessels fenestrated
A
no- unfenestrated.
12
Q
How many layers of cells do lymphatic vessel have? what kind of cells?
A
1 layer of attenuated endothelial cells
13
Q
What is lymphedema? what is the cause? treatment?
A
- Elephantitis due to clockage of lymph flow resulting a buildup of lymph fluid.
- Can be either inherited (primary) or caused by injury/disease of lymph vessels (secondary)
- ex: after lymph node dissection, surgery. filariasis (tropical parasitic infection from nematode colonizing lymph system and blocking flow) or cellulitis (inflammation/infection of lymphatic system)
-treatment: treat with compression and gradient pumps
14
Q
What is lymphangitis? causes?
A
Lymph Vessel Inflammation from bacteria in the lymphs system. acute form bacteria or it can be secondary to malignancy.
at risk if had a masectomy, leg vein removed for bypass
15
Q
What is the relation between cancer metastasis and the lymph system
A
cancerous cells can use the lymph system to spread from one place to another - especially common with pancreatic and breast cancer
16
Q
Which cells belong to the innate immune system?
A
NK cells, neutrophils and macrophages. the complement system.
17
Q
WHich cells are in the adaptive immune system
A
B and T cells and APC cells
18
Q
Does the adaptive system get better or worse at responding to an invaders with subsequent confrontations?
A
better
19
Q
B cells; where do they generate? what do they make?
A
Generate and differentiate in bone marrow (bursa). Make antibody and participate in humoral immune response. plasma cells and memory B cells.
20
Q
T cells; where do they generate?
A
generate in the bone marrow and differentiate in the thymus. participate in cell mediated immune response. cytotixic, helper, suppressor and memory t-cells
21
Q
How do adaptive immune cells communcate with each other?
A
cytokines which are released in response to encounters with foreign substances called antigens
22
Q
what makes antibodies
A
B cells
23
Q
IgA
A
secretory antibody
24
Q
IgD
A
activates B cells
25
IgE
degranualtes mast cells and basophils
26
IgG
most common, opsonin, NK cytotoxicity
27
IgM
1st isotype forme din primary response
28
What are the primary lymphatic organs?
thymus, pre/postnatal bone marrow, fetal liver
29
what is the fxn of primary lymph organs
development and maturation of lymphocytes into mature immunocompetent cells
30
what are the secondary lmphyoid organs
lymph nodes, spleen, MALT, postnatal bone marrow
31
What is the function of secondary lymphoid tissues
mature distribution of lymphoid cells. respondible for the appropriate environment for immunocompetent cells to interact with each other, antigens and with other cells to mount an immune response against invading pathogens.
32
What are the unencapsulated lymphatic organs
MALT, BALT , GALT tonsil
| also known as diffuse
33
Where is the thymus? fxn?
located in the superior mediastinum and extending over the vessels of the heart.
site of t cell maturation - competence of T cells and elimination of self-reactive T cells
34
How many lobes does the thymus have
2
35
What are lobules in the thymus?What forms them?
incomplete division of the lobes formed by septa (trabeculae) extending into the lobes of the dense connective tissue of the thymus capsule
36
What is the dark staining part of a thymus? the light staining?
dark: cortex (bc it has the cells proliferating)
light: medullar
37
What is the name of the cells that migrate from the bone marrow to the thymus? what are they
thymocytes which are immature immuno-incompetent T cells
38
Where do thymocytes first migrate to in the thymus
periphery of the cortex and move progressibvely deeper with maturation
39
What type of cells do you find in the thymus cortex
macrophages/APCs, epithelial reticular cells (provide structure)
40
What are the two types of selection that thymocytes go through in thymus
positive and negative selection
41
What happens to the thymocytes that do not pass the selection in thymus
they undergo anergy or apoptosis
42
What is positive selection of T cells in the thymus
Recognition of MHC 1/2 by CD4/8 molecules presented by APC.
```
In order to be positively-selected, thymocytes will have to interact with several cell surface molecules, MHC/HLA, to ensure reactivity and specificity.[19]
Positive selection eliminates (apoptosis) weak binding cells and only takes high medium binding cells. (Binding refers to the ability of the T-cell receptors to bind to either MHC class I/II or peptide molecules.)
```
43
What is negative selection of T cells in the thymus
elimination of T-cells that are autoreactive
44
Where do Thymocytes go that pass both selections? what are they called now
medulla, now called immature T cells
45
What is the identifying feature of the thymus medulla
Hassall's corpsucles
46
What makes up Hassall's corpsucles? where do you find them
in thymus mediulla. made of type 4 reticular cells
47
WHat stimulates maturation in the thymus
hormones produced by epithelial reticular cells
48
What is the purpose of the blood thymus barrier
regulates exchange of substances between the circulatory system and thymus, providing a sequestered environment for immature T cells to develop. The barrier also prevents the immature T cells from contacting foreign antigens (since contact with antigens at this stage will cause the T cells to die by apoptosis).
The barrier is formed by the continuous blood capillaries in the thymic cortex, reinforced by epithelial reticular cells and macrophages.
49
WHere is the blood thymus border
cortex
50
what is thymic involution
as the thymus ages it begins to involute and decrease its ability to generate educated T cells.
adipocytes replace the parenchyma
51
how long do B cells live
10 days to 15 months
52
how long do killer t cells live? helper
about one year. helper are more like 26 weeks.
53
Are lymph nodes primary or secondary lymphoid organs? big or small? encapsualted?
secondary small encapsulated organs
54
What are the two main functions of lymph nodes
Lymph filtration, antigen presentation and recognition
55
What is lymph filtration in the lymph nodes
removal of bacteria and foreign substances from the lymph by macrophages in the sinuses
56
What happens if a antigen is recognized in a lymph node
B cell is activated and migrates to primary lymphoid nodule and proliferates forming a germinal center and makes a secondary lymphoid nodule
57
What is the lymph node capsule made of?
dense collagneous tissue
58
Does the lymph node have trabeculae
Yes
59
What type of tissue forms the framework of the lymph node
reticular connective tissue
60
Is lymph entry into the node on the convex or concave sidee
convex side
61
For lymph filtration in the nodes where does lymph from vessels go ?
hint: three sinsus
subcapsular sinsus to the corticol sinus to the medullary sinus
62
What part of the cortex do B and T cells enter the lymph node? via what?
The paracortex via the high endothelial venules
63
After entry to the paracortex of the lymph node where do B cells go
cortex- primary lymphoid nodules
64
After entry to the paracortex of the lymph node where do B cells go
stay in paracortex
65
What is a lymphoid nodule? What are the two areas that make it up
a spherical aggregate of B cells. the center is called the germinal center and the outside circle the mantle zone
66
What is the mantle zone
a dense accumulation of B lymphocytes migrating out from germinal center
67
what is the germinal center?
where B cells proliferate migrate express soluble Igs (sIgs), switch IG class etc
68
What happens to B cells in the germinal center that do not make the proper sIgs
apoptosis and undergo phagocytosis by macrophages
69
Where do the majority of B cells go after the secondary lymphoid nodules
to medulla and form medullary cords that go to medullary sinuses.
70
Where do the majority of the plasma B cells leaving the efferent lymphatic vessels of the nodes go
bone marrow to produce antibodies
71
Where do the majority of the memory B cells leaving the efferent lymphatic vessels of the nodes go
take up residence in other secondary lymphatic organs
72
What are the two zones of the germinal center? what is the funciton of the two zones
The dark and light zone.
dark zone is where there is clonal expansion (naive B cells go here first) and the light zone is where there is selection apoptosis differentiation etc.
73
Where do T cells leave the nodes?
Medullary sinuses (just like B cells)
74
What is the thymus dependent region of the lymph node?
Paracortex bc that is where all the T cells are
75
Why do we get swollen lymph nodes when sick
If Th cells are activated they proliferate and expand the paracortex
76
What are functions of the spleen?
blood filrtation, lymphoid cell formation (T and B cell proliferation), elimination or inactivation of blood-borne antigen, destroys old platelets/RBCs, fetal hematopoeiss (and adult if needed)
77
Where is the Hilum in the spleen and lymph nodes? fxn?
concave surgace it is the entry point of arteries and nerve fibers.
78
What are the two "pulps" of the spleen? where does the blood first enter
white and red. blood enters through splenic artery in white pulp
79
Where does the blood go from the splenic arteries in the spleen
To trabecular arteries to the central arteries. this is all WHITE PULP from central they go pencillar arteries which is RED PULP
80
What are PALS in the spleen? Where do yoy find it
Periarterial lymphatic sheath. found around the central artery in the whilte pulpbut not around the pencillar arteries in the red pulp
81
What does red pulp look like in a fresh but spleen section? H&E?
in fresh cut red, pink in H&E
82
What happens in the red pulp
filters the blood, removing organisms and aged RBCs and platelets.
83
What does the white pulp look like? fx?
gray in fresh cut section and purple in h&e.
it has the lymphoid nodules and PALS
part of the infection fighting immune system. it makes lymphocytes and antibodies
84
Where do you find the splenic sinuses? what do the look like
Red pulp, sinusoids/spaces that have a discontinuous basal lamina
closed circulation
85
WHERE do you find the splenic cords of bilroth? what are they
red pulp
sponge material composed of a loose network of reticular fibers.
open circulation
86
Where does the pencillar arteries lead?
3 places: pulp arterioles, terminal arterial capillaries and macrophage sheathed areterioles
we focus on terminal
87
Where do the terminal arterial capillaries go
Splenic sinuses or splenic cords of bilroth
88
How do closed circulation splenic sinuses exit the spleen
become trabecular veins to the spleinc vein and exit at the hilum
89
where do B and T cells enter the spleen? where do the exit?
enter and exit at the marginal zone around the white pulp through marginal sinuses
90
What is the marginal zone of the spleen
surrounds the white pulp and separates it form the red pulp. it where t and b lymphocytes enter and exit the spleen
91
Where do T and B cells go in the spleen once in the white pulp? Do they stay in there?
PALS. T cells stay in PALS B cells migrate to lymphoid nodules that enclosed within the pals
92
What is MALT?
Mucosal Associated Lymphoid Tissue. nonencaprulated localized lymphocyte infiltration and lymphoid nodules in the muscosa of the GI, resp and urinary tracts.
93
What is the function of MALT/
reponse to airborne/ingested antigens
94
Where can you find GALT
most prominent in the ileum called Peyer's Patches.
| they are in the GI tract
95
What makes up GALT
B surrounded by a looser region of T cells and APCs
96
Is there afferent and efferent drainage in GALT
No just efferent.
97
Where are M cells? what do they do
GALT and BALT aka microfold cells. in the epithelial lining next to the lymphoid follicles thought to capture antigens and transfer them to macrophages in the Peyer's pathces/BALT
98
What is BALT
Bronchus associated lymphoid tissue
| it is like peyers patches but in the walls of the bronchi
99
What are most cells in BALT
B cells.
100
Are tonsils encapsulated?
nope they are incompletley encapsulated aggregates of lymphoid nodules that guard entrance to the oral pharynx
101
How do tonsils react
by lymphocyte proliferation and mounting an immune response
102
What are the three types of tonsils
palatine, pharyngeal, lingual
103
Where is the palatine tonsil
at the boundary of the oral cavity and oral pharynx
104
What covers the superficial aspect on the palatine tonsil
an epithelial layer that dips into 10-12 crypts into the tonsilar parenchyma
105
what is in the parenchyma of the palatine tonsil
lymphoid nodules which display genrminal centers (for B cell activation)
