The Lymphoid System

Question 1

name the primary and secondary lymphoid tissues

Answer 1

Central (Primary) lymphoid tissues
Bone marrow
Thymus
Peripheral (Secondary) lymphoid tissues
Lymph nodes
Spleen
Tonsils (Waldeyer’s ring)
Epithelio-lymphoid tissues
Bone marrow

Question 2

what size should lymphnodes be?

Answer 2

Up to 2.5cm

Question 3

what is the vascular supply of the spleen?

Answer 3

Supplied by splenic artery (branch of coeliac axis) and drained by splenic vein (with SMV forms portal vein)

Question 4

what does the white pulp consist of

Answer 4

Periareriolar lymphoid sheath- contains T helper cells

APC’s activate response

Question 5

what is the hypersplensim triad?

Answer 5

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

Question 6

what conditions cause splenomegaly?

Answer 6

Infection
Wide range: EBV, Malaria, TB, Typhoid, Brucellosis, Leishmaniasis, Trypanosomiasis,
Congestion
Portal (Hepatic cirrhosis, portal/splenic vein thrombosis, cardiac failure)
Haematological diseases
Lymphoma/leukaemia, haemolytic anaemia, ITP, Myeloproliferative disorders
Inflammatory conditions
Rheumatoid arthritis, SLE
Storage diseases
Gaucher’s, Niemann-Pick disease
Miscellaneous
Amyloid, Tumours (primary and metastatic), cysts

Question 7

what are the signs of hyposplenism?

Answer 7

Howell-Jolly bodies
Other red cell abnormalities
May also be some immune deficiency – especially if spleen removed in childhood

Question 8

what are causes of hyposplenism

Answer 8

Splenectomy

Coeliac disease
Sickle cell disease
Sarcoidosis
Iatrogenic – non-surgical