Lymphoid System

Question 1

Name the primary lymphoid organs

Answer 1

Bone marrow

Thymus

Question 2

Name the secondary lymphoid organs

Answer 2

Lymph nodes 
Spleen 
Tonsils 
Epithelia-lymphoid tissues 
Bone marrow

Question 3

What are the functions of lymphatics?

Answer 3

Fluid homeostasis
Allows cell traffic and trapping
Allows interaction with cells and the immune system

Question 4

Describe the structure of lymph nodes

Answer 4

Small oval bodies located along the course of lymphatic vessels
Afferent channels
Efferent vessels
Medulla and follicles surrounding a hilum

Question 5

Where do the efferent vessels drain?

Answer 5

Cisterna chyli/thoracic duct
R/L jugular, subclavian or brachomediastinal trunks
Into venous system at junction of subclavian and jugular veins

Question 6

Where is lymph filtered?

Answer 6

Node parenchyma

Question 7

What does lymph filtration allow?

Answer 7

Traffic of cells

Immune interactions

Question 8

What role does lymph play in the immune system?

Answer 8

Houses cells of innate immune system
Traffic of APCs links innate and adaptive
Adaptive immune response

Question 9

What immune cells can be found in a lymph node?

Answer 9

Lymphocytes 
Mononuclear phagocytes 
APCs
Dendritic cells 
Endothelial cells

Question 10

Where are B cells found?

Answer 10

Follicles
Germinal centres
Interfollicular area
Plasma

Question 11

What can cause lymphadenopathy?

Answer 11

Local inflammation
Systemic inflammation
Malignancy
Others - sarcoid, castleman’s

Question 12

What is lymphangitis?

Answer 12

Red lines extending from an inflamed lesion of superficial infection

Question 13

Describe how cell pattern can indicate cause

Answer 13

Predominant B cell - autoimmune/infection
Predominant phagocyte - tumour
Predominant T cell - virus/drugs

Question 14

Where is the spleen?

Answer 14

Upper left quadrant of abdomen

Question 15

Name the two surfaces of the spleen

Answer 15

Diaphragmatic surface

Visceral surface

Question 16

What makes up the visceral surface?

Answer 16

Left kidney, gastric fungus, tail of pancreas, splenic flexure of colon

Question 17

Describe the vasculature of the spleen

Answer 17

Supplied by the splenic artery - branch of coeliac

Drained by splenic vein (contributes to SMV to portal vein)

Question 18

Name the two key parts of the spleen

Answer 18

Red pulp

White pulp

Question 19

What is found in the red pulp?

Answer 19

Sinusoids

Cords

Question 20

What supports the sinusoids?

Answer 20

Hoops of reticulin

Question 21

What do cords contain?

Answer 21

Macrophages, fibroblasts, cells in transit

Question 22

What makes up the white pulp?

Answer 22

Peri-arteriolar lymph sheath (PALS). APCs in white pulp present antigen to immune reactive cells

Question 23

What is the function of the spleen?

Answer 23

Detect, retain and eliminate unwanted foreign/damaged material
Facilitate immune responses to blood borne antigens

Question 24

State the hypersplenism triad

Answer 24

1. splenomegaly
2. fall in one or more cellular components
3. correction of cytopenias by splenectomy

Question 25

How does splenomegaly present?

Answer 25

Dragging sensation in LUQ

Discomfort with eating

Question 26

State the causes of splenomegaly

Answer 26

Infection 
Congestion - portal 
Haematological 
Inflammatory 
Storage disease 
Miscellaneous (amyloid, tumours, cysts)

Question 27

What can cause hyposplenism?

Answer 27

Splenectomy

Coeliac, sickle cell, sarcoidosis, iatrogenic

Question 28

What cells can be seen in reduced red pulp?

Answer 28

Howell Jolly bodies