Lymphoid structures

Question 1

Lymph node - general anatomy (gross)

Answer 1

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)

Question 2

Lymph node - afferents vs efferents

Answer 2

many afferents and 1 or more efferents

Question 3

Lymph node - trabeculae structure

Answer 3

fibrous capsule extends to form trabeculae

Question 4

The lymph parenchyma is divided into (functionally)

Answer 4

1. Follicle of cortex
2. Paracortex
3. Medulla

Question 5

Lymph node - function

Answer 5

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

Question 6

Lymph node - Follicle

Answer 6

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

Question 7

Lymph node - Follicle - 1ry vs 2ry

Answer 7

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

Question 8

Lymph node - medulla

Answer 8

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

Question 9

Lymph node - medulla conistis of (and contain)

Answer 9

1. medullary cord –> lymphocytes and plasma cells

2. medullary sinus –> reticular cells and macrophages

Question 10

Lymph node - Paracortex

Answer 10

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

Question 11

lymphoid tissue - Parenchymal anatomy - from outter to inner

Answer 11

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

Question 12

lymph tissue - site of B-cell localization and proliferation

Answer 12

Follicle

Question 13

lymph tissue - area of macrophages and medullary cords plasma cells

Answer 13

macrophages –> medullary sinus

lymphocytes –> medullary cords

Question 14

Lymph node - Paracortex not well developed in / enlarge in

Answer 14

not well –> DiGeorge syndrome

enlarges –> extreme cellular immune response (eg. viral)

Question 15

Cervical lymph node cluster drains … (area)

Answer 15

head and neck

Question 16

Hilar lymph node cluster drains … (area)

Answer 16

lungs

Question 17

Mediastinal lymph node cluster drains … (area)

Answer 17

Trachea and esophagus

Question 18

Axillary lymph node cluster drains … (area)

Answer 18

Upper limb, breast, skin above umbilicus

Question 19

Celiac lymph node cluster drains … (area)

Answer 19

liver, stomach, spleen, pancreas, upper duodenum

Question 20

Superior mesenteric lymph node cluster drains … (area)

Answer 20

lower duodenum, jejunum, ilieum, colon to splenic fructure

Question 21

Inferior mesenteric lymph node cluster drains … (area)

Answer 21

colon from splenic flexure to upper rectum

Question 22

Internal iliac lymph node cluster drains … (area)

Answer 22

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

Question 23

Para-aortic lymph node cluster drains … (area)

Answer 23

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

Question 24

The paraaortic lymph nodes lie ….

Answer 24

in front of the lumbar vertebrae near the aorta

Question 25

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

Answer 25

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

Question 26

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

Answer 26

immediately below the inguinal ligament.

Question 27

Popliteal lymph node cluster drains ... (area)

Answer 27

dorsolateral foot, posterior calf

Question 28

Lymph ducts - function

Answer 28

- 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

Question 29

spleen parenchyma is divided to (and locations)

Answer 29

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

Question 30

Speen sinusoids?

Answer 30

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

Question 31

spleen - cells and their location

Answer 31

- 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)

Question 32

spleen - role of Marginal zone

Answer 32

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

Question 33

spleen - role of macrophages

Answer 33

remove encapsuled bacteria

Question 34

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

Answer 34

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

Question 35

Encapsuled bacteria - their capsule serve as an

Answer 35

anthiphagocytic viruence factor

Question 36

asplenic patients - vaccines and their structure

Answer 36

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

Question 37

Postsplenectomy - lab findings (and mechanism)

Answer 37

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

Question 38

Thymus - function

Answer 38

site of T-cell differentiation and maturation

Question 39

Thymus - gross anatomy and location

Answer 39

encapsuled | located in anteriosuperior mediastinum

Question 40

Thymus embriology

Answer 40

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

Question 41

Thymus - histology

Answer 41

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

Question 42

Thymus - situations that change its size

Answer 42

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

Question 43

spleen - follicle anatomy

Answer 43

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

Question 44

spleen - types of circulation (and area)

Answer 44

1. open circulation (sinusoids) | 2. closed circulation