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Flashcards in Lymphoid structures Deck (44):
1

Lymph node - general anatomy (gross)

is a 2ry lymphoid organ that has many afferents and 1 or more efferents. Encapsuled, with trabeculae (fibrous capsule extends to form trabeculae)
bean shape
It has a hilum (blood vessels and efferent lymphatics)

2

Lymph node - afferents vs efferents

many afferents and 1 or more efferents

3

Lymph node - trabeculae structure

fibrous capsule extends to form trabeculae

4

The lymph parenchyma is divided into (functionally)

1. Follicle of cortex
2. Paracortex
3. Medulla

5

Lymph node - function

1. nonspecific filtration by macrophages
2. storage of B and T cells
3. immune response activation

6

Lymph node - Follicle

Site of B-cell location and proliferation. In outer cortex
1ry follicles are dense and dormant. 2ry have pale central germinal centers and are active

7

Lymph node - Follicle - 1ry vs 2ry

1ry follicles are dense and dormant. 2ry have pale central germinal centers and are active

8

Lymph node - medulla

Consist of medullary cords (closely packed lymphocytes and plasma cells) and medullary sinus. Medullary sinus communicate with efferent lymphatics and contain reticular cells and macrophages

9

Lymph node - medulla conistis of (and contain)

1. medullary cord --> lymphocytes and plasma cells
2. medullary sinus --> reticular cells and macrophages

10

Lymph node - Paracortex

Houses T cells. Region of cortex between follicles and medulla. Contains high endothelial venules (postcapillary) through which T cells and B cells enter enter from blood

11

lymphoid tissue - Parenchymal anatomy - from outter to inner

outer - capsule (with trabecula) - subcapsular - cortex (follicle of cortex and inner the paracortex) - medullar - inner

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lymph tissue - site of B-cell localization and proliferation

Follicle

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lymph tissue - area of macrophages and medullary cords plasma cells

macrophages --> medullary sinus
lymphocytes --> medullary cords

14

Lymph node - Paracortex not well developed in / enlarge in

not well --> DiGeorge syndrome
enlarges --> extreme cellular immune response (eg. viral)

15

Cervical lymph node cluster drains ... (area)

head and neck

16

Hilar lymph node cluster drains ... (area)

lungs

17

Mediastinal lymph node cluster drains ... (area)

Trachea and esophagus

18

Axillary lymph node cluster drains ... (area)

Upper limb, breast, skin above umbilicus

19

Celiac lymph node cluster drains ... (area)

liver, stomach, spleen, pancreas, upper duodenum

20

Superior mesenteric lymph node cluster drains ... (area)

lower duodenum, jejunum, ilieum, colon to splenic fructure

21

Inferior mesenteric lymph node cluster drains ... (area)

colon from splenic flexure to upper rectum

22

Internal iliac lymph node cluster drains ... (area)

Lower rectum to anal canal (above pectinate line), bladder, middle third of vagina, prostate, cervix, corpus carvenosum

23

Para-aortic lymph node cluster drains ... (area)

1. Testes 2. ovaries 3. kidneys 4. uterus

24

The paraaortic lymph nodes lie ....

in front of the lumbar vertebrae near the aorta

25

Superficial inguinal lymph node cluster drains ... (area)

anal canal (below pectinate line), skin below umbilicus (except popliteal territory), scrotum, vuvla , distal vagina

26

The superficial inguinal lymph nodes form a chain .... (area)

immediately below the inguinal ligament.

27

Popliteal lymph node cluster drains ... (area)

dorsolateral foot, posterior calf

28

Lymph ducts - function

- Right lymphatic duct drains right side of body above diaphragm into juction of left subclavian and internal jugular veins
- Thoracic duct drains everything else into junction of left subclavian and internal jugular veins

29

spleen parenchyma is divided to (and locations)

1. white pulps (centrally)
2. red pulps (RBCs) (peripherally)
3. marginal zone (between red and white pulps)

30

Speen sinusoids?

long, vascular channels in red pulp with fenestrated "barrel hoop" basement membrane

31

spleen - cells and their location

- T cell: periarteriolar lymphatic sheath (white pulp)
- B cell: follicles (white pulp)
- macrophages and specialized B cells: Marginal zone
- macrophages: Cords of Billroth (red purples)

32

spleen - role of Marginal zone

it contains macrophages and specialized B cells --> APCs capture blood-borne antigens for recognition by lymphocytes

33

spleen - role of macrophages

remove encapsuled bacteria

34

splenic dysfunction - problem (and mechanism) (and example of spleen dysfunction

low IgM synthesis --> decreased complement activation
--> decreased C3b opsonization --> increased susceptibility to encapsuled organisms
example --> 1. postsplenoctomy 2. sickle cell anemia

35

Encapsuled bacteria - their capsule serve as an

anthiphagocytic viruence factor

36

asplenic patients - vaccines and their structure

1. S. pneumoniae --> PCV conjugate (Prevnar) , PPSV non congugate (Pneumovax)
2. H. influenzae type B--> conjugate
3. N. meningitidis --> conjugate

37

Postsplenectomy - lab findings (and mechanism)

1. Howell-jolly bodies (nuclear remnants)
2. Target cells
3. Thrombocytosis (loss of sequestration and removal)
4. Lymphocytosis (loss of sequestration)

38

Thymus - function

site of T-cell differentiation and maturation

39

Thymus - gross anatomy and location

encapsuled
located in anteriosuperior mediastinum

40

Thymus embriology

thymus --> third pharyngeal pounch
Lymphocytes --> mesenchymal

41

Thymus - histology

- cortex is dense with immature T cells
- medulla is pale with mature T cells and Hassal corpuscles containing epithelial reticular cells

42

Thymus - situations that change its size

1. hypoplastic in DiGeorge syndrome and severe combined immunodeficiency
2. Enlarged in myasthenia gravis

43

spleen - follicle anatomy

germinal center in the middle --> mantle zone --> marginal zone

44

spleen - types of circulation (and area)

1. open circulation (sinusoids)
2. closed circulation