Lymphoid system

Question 1

What are lymph nodes?

Answer 1

• small, oval bodies (2.5cm)

- found along the COURSE of lymphatic vessels

Question 2

What do LNs do?

Answer 2

• blind-ending vascular channels COLLECT fluid from TISSUES and returns to blood stream
• PASSIVE movement of fluid
• valves

Question 3

LNs found in the intestinal wall are called ______

Answer 3

PEYER’s PATCHES

Question 4

What is the function of lymph nodes?

Answer 4

1. filter blood

2. assist the immune system in building an immune response

Question 5

Describe the flow of lymph through the lymph nodes.

Answer 5

• the AFFERENT channels drain lymph through the CAPSULE into the PERIPHERAL sinus

> lymph then moves towards the HILUM of the lymph node

> concave area in the node that drains lymph into the EFFERENT channels = FILTERED lymph

Question 6

Name the lymphatic trunks.

Answer 6

1. 2 lumbar trunks
2. 2 bronchomediastinal trunks
3. 2 jugular trunks
4. 2 subclavian trunks
5. 1 intestinal trunk

Question 7

What are the 2 major ducts of the lymphatic system?

Answer 7

1. Thoracic Duct

2. Right lymphatic duct - drains lymph from the Right arm, right side of HEAD and chest

Question 8

What does the right lymphatic duct then do?

Answer 8

• drain blood into the jxn of the RIGHT JUGULAR vein and the RIGHT subclavian vein

Question 9

Where does the thoracic duct dump lymph into?

Answer 9

• same jxn on the left side of body

- —–jxn of the Left subclavian and left jugular vein

Question 10

What cells does the lymphoid system house?

Answer 10

• cells of the INNATE immune system
  1. Lymphocytes: B-cells/ T-cells/ NK-cells

2. Mononuclear phagocytes (macrophages/ Antigen presenting cells and dendritic cells)
3. endothelial cells

Question 11

Where are the plasma cells located in the lymph node?

Answer 11

• in the MEDULLA

Question 12

What are forms of lymphadenopathy?

Answer 12

1. local inflammation
2. systemic inflammation
3. malignancy
4. others: Sarcoidosis/ catslemans disease/ IgG4-related disease

Question 13

What are causes of local inflammation?

Answer 13

1. infection (TB or Toxoplasma)

2. vaccination/ dermatopathic

Question 14

What are causes of systemic inflammation?

Answer 14

1. viral infections

2. autoimmune

Question 15

WHat is sarcoidosis?

Answer 15

• a granulomatous condition
• WIDE DDX; no histological dx
• –may mask malignancy in a LN

Question 16

what is lymphangitis?

Answer 16

• superficial infection (RED lines EXTENDING form an inflamed lesion)

Question 17

What may be the first sign of UNDERLYING malignancy?

Answer 17

• superficial lymphadenopathy

Question 18

What could it be if pt presents with GENERALIZED lymphadenopathy?

Answer 18

• inflammatory process

- widespread malignancy (lymphoma/ leukaemia) —FBC check!

Question 19

Name a IIary lymphoid organ.

Answer 19

SPLEEN

(normally 150-200g) —usually NOT palpable !

Question 20

What is contact with the spleen’s visceral surface?

Answer 20

• left kidney
• gastric fundus
• tail of pancreas
• splenic flexure of colon

Question 21

What is the spleen supplied by?

Answer 21

splenic artery (br. of the coeliac axis)
---drained by the splenic vein ----SMV forms the portal vein

Question 22

What is a diseased spleen prone to ?

Answer 22

RUPTURE

- why it’s an emergency

Question 23

What is the fxn of the spleen?

Answer 23

FILTER for the blood
- detects, retains and eliminates UNWANTED, foreign/ damaged material

• facilitates immune responses to blood borne antigens!

Question 24

Describe the morphology of the spleen.

Answer 24

-encapsulated organ with parenchyma, including RED PULP and WHITE pulp

Question 25

What makes up the red pulp in the spleen?

Answer 25

``` contains SINUSOIDS (fenestrated, lined by endothelial cells and supported by reticulin) ``` CORDS containing macrophages and some fibroblasts and cells (RBCs/ WBC/ PC and some CD8+ T cells) in transit

Question 26

Why should splenic rupture always be considered in abdominal injuries?

Answer 26

- it only has a thin capsule and it is a well-vascularized organ

Question 27

What is the white pulp of the spleen?

Answer 27

LYMPHATIC tissue of the spleen: - periarteriole lymphatic sheath (lymphoid organ- T-cells and marcophage) - marginal zone (macrophages) - follicles (B-cells)

Question 28

Describe the circulation of blood within the spleen.

Answer 28

- splenic artery> central arterioles> end arterie s

Question 29

What % of the spleen makes up 25% of it?

Answer 29

White matter

Question 30

How does blood return with the venous system in the spleen?

Answer 30

- through the sinus system; found all around the capillaries (which have fevenstrations) > v.sinus > collecting vein> splenic vein

Question 31

What % if the spleen is made up by the red pulp?

Answer 31

75% | - resp. to screen for abnormal RBCs, OLD rbc

Question 32

WHat may be a sign of splenectomy/ hyposplenism?

Answer 32

- presence of abnormal red cells in the peripheries. | (Howell-Joly bodies- remnants of

Question 33

What is seen in the peri-arteriolar lymphoid sheath?

Answer 33

- CD4+ lymphoid cells | - --PALS is explanded by lymphoid follicles

Question 34

How does splenomegaly present as?

Answer 34

- LUQ DRAGGIN sensation - discomfort with EATING - pain if infarction - HYPERSPLENISM

Question 35

What occurs with hypersplenism?

Answer 35

TRIAD 1. splenomegaly 2. FALL in 1/more cellular components 3. correction of CYTOPENIAS by splenectomy

Question 36

What infection may cause splenomegaly?

Answer 36

``` EBV TB Malaria Typhoid Brucellosis Leichmaniasis trypanosomiasis ```

Question 37

What inflammatory conditions results in splenomegaly?

Answer 37

RA | - SLE

Question 38

Name congestive causes of splenomegaly.

Answer 38

portal (hepatic cirrhosis/ splenic vein thrombosis. cardiac failure)

Question 39

Name haematological diseases leading to splenomegaly.

Answer 39

1. lymphoma/leukaemia 2. Haemolytic anaemia 3. ITP 4. Myeloproliferative d.o

Question 40

Storage causes of splenomegaly.

Answer 40

Gaucher's | Niemann-Pick disease

Question 41

When may hypersplenism occur?

Answer 41

with conditions a.w splenomegaly

Question 42

Apart from splenectomy, what are other causes of hyposplenism?

Answer 42

1. coeliac disease 2. sickle cell disease 3. sarcoidosis 4. iatrogenic (non-surgical)

Question 43

Hyposplenism occurs with loss of fxn of which pulp?

Answer 43

RED pulp