Lymphoid Structures and Lymphoctes EC Flashcards Preview

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Flashcards in Lymphoid Structures and Lymphoctes EC Deck (42):
1

What occurs in the lymph node follicle? What is the difference between a primary and secondary follicle?

B-cell localization and proliferation

Primary follicles dense and dormant
Secondary follicles active with pale germinal centers

2

What occurs in the paracortex? When would this area be enlarged?

House T-Cells

Enlarged in extreme cellular immune response (ie virus)
would NOT be enlarged in DiGeorge (no thymus)

3

Lymph node drainage of the upper limb and lateral breast

Axillary nodes

4

Lymph node drainage of Stomach

Celiac nodes

5

Lymph node drainage of Duodenum and Jejunum

Superior mesenteric nodes

6

Lymph node drainage of Sigmoid colon

Colic then Inferior mesenteric nodes

7

Lymph node drainage of Rectum and Anal canal (above pectinate line)

Internal iliac nodes

8

Lymph node drainage of Anal canal below pectinate line

Superficial inguinal nodes

9

Lymph drainage of testes

Para-aortic nodes

10

Lymph drainage of scrotum

Superficial inguinal nodes

11

Lymph drainage of thigh

Superficial inguinal nodes

12

Lymph drainage of lateral dorsum of foot

Popiteal nodes

13

What does the Right lymphatic duct drain?

Right arm
Right chest
Right half of face

14

What does the thoracic duct train? Where does it drain?

All but R-arm, R-chest, and R-face

Drains at junction of Subclavian and Internal Jugular veins

15

Does lymphatic blockage result in pitting or non-pitting edema?

Non-pitting edema (filled with protein, fat, etc.)

16

Within the spleen, where are T-Cells found?

PALS (periarterial lymphatic sheath)

17

Within the spleen, where are B-Cells found?

In follicles

18

What is the function of macrophages within the spleen?

To remove encapsulated bacteria

"Even Some Killers Have Nice Shiny Bodies"

E. coli
Strep. pneumoniae
Klebsiella pneumoniae
H. influenzae
Neisseria meningitidis
Salmonella
B Strep

19

What findings are their post-splenectomy?

Howell-Jolly bodies (RBC nuclear remnants)
Target cells
Thrombocytosis (increased platelets)

20

Thymus appearance and selection that takes place in each region

Cortex is DENSE with IMMATURE T-Cells
~Positive Selection (MHC restriction)

Medulla is PALE with MATURE T-Cells
~Negative Selection (Nonreactive to self)

21

What are M cells?

Present in gut

Present antigens from gut to Lymphocytes

22

Innate Immune System

Nonspecific - No memory

PMNs, Macrophages, Dendritic Cells, NK cells, Complement

23

Adaptive Immune System

Receptors that recognize pathogen undergo V(D)J recombination during development

Response slow at first exposure, but fast and robust with memory

T-Cells, B-Cells and circulating antibody

24

MCH I

HLA-A, HLA-B, HLA-C

Binds TCR and CD8

Express on ALL NUCLEATED CELLS (ie not RBCs)

Antigen loaded into ER (intracellular peptides)
Viral immunity

25

MHC II

HLA-DR, HLA-DQ, HLA-DP
"Dr. went into DQ to get a Dr. Pepper"

Binds TCR and CD4

Expressed only on APCs (dendritic, macrophage, B-cell, M-cell)

26

Natural Killer Cells

Use Perforin and Granzymes to induce apoptosis in virally infected cells and tumor cells (similar to CD8 T cells)

Enhanced by IL-2, IL-12, IFN-beta, IFN-alpha

Kill with non-specific antigen or no MHC I expressed

27

B cell major functions

Make antibody
Opsonize bacteria (IgG)
Neutralize viruses (IgG)
Activate complement (IgG, IgM)
Sensitize mast cells (IgE)

Hyperacute and humoral organ rejection

28

T cell major functions

CD4 T cells:
Help B cells make antibody
Produce cytokines to activate other cells

CD8 T cells:
Kill virus infected cells and tumor cells
Acute and chronic cellular organ rejection

29

Naive T Cell activation

Foreign body phagocytosed by APC
Antigen presented on MHC and recognized by TCR
Costimulatory signal of B7-CD28
Helper T cell produces cytokines
Cytotoxic T cell activates, recognizes, and kills virus infected cell

30

B cell activation and class switching

B cell presents antigen on MHC II to TCR of CD4 cell
CD40 binds CD40L on T-cell
CD4 cell secretes cytokines that determine Ig class switching of B cell

31

Th1 CD4 Cells (Secrete, Activate what, Inhibited by)

Secrete IFN-gamma

Activate macrophages

Inhibited by IL-4 and IL-10 (from Th2 cell)

32

Th2 CD4 Cells (Secrete, Activate what, Inhibited by)

Secrete IL-4, IL-5, IL-10, IL-13

Recruits eosinophils for parasitic defenses
Promotes IgE production

Inhibited by IFN-gamma (from Th1 cell)

33

Cytotoxic T Cells

Release Perforin and Granzyme (killing virus infected cells and tumor cells)

34

Regulatory T Cells

Suppress CD4 and CD8 functions

Express CD3, CD4, CD25

Produce anti inflammatory cytokines IL-10, TGF-beta

35

Idiotype

Specific antibody that Ig binds

36

Isotype

Type of antibody

IgM vs IgG etc.

37

IgG

Delayed response to antigen (most abundant)

Fixes complement
Crosses placenta
Opsonizes bacteria
Neutralizes bacterial toxins and viruses

38

IgA

Prevent attachment to mucous membranes

Found in secretions

39

IgM

Early response to antigen

Fixes complement
Traps free antigens while humoral response evolves

40

IgE

Bind mast cell and basophil --> HISTAMINE release

Immunity to worms by activating eosinophils

41

Thymus-independent antigens

No protein content

Stimulate antibody release but NO MEMORY

42

Thymus-dependent antigens

Protein content

Stimulate class switching and MEMORY