Lymphoid cells and Lymphadenopathy Flashcards
Where does T cell maturation take place?
thymus
Where does B cell maturation take place?
bone marrow
What are primary lymphoid tissues?
bone marrow and thymus
What are secondary lympoid tissues?
lymph nodes spleen tonsils epithelio-lympoid tissue bone marrow
What is a normal size of a lymph node?
up to 25cm
What is the role of a lymph node?
collect fluid from tisseus and return it to the blood stream - filtered to the node parenchyma
Where do afferent vessels drain lymph to?
through the capsule -> peripheral sinus
Where do eferent vessels drain lymph to?
leaves the hilum and drains to the cisterna chylii, thoracic duct, L or R jugular, subclavian or bronchomediastinal trunks
What can cause lymphadenopathy?
local inflammation - TB, toxoplasma
systemic inflammation - infection (viral) or autoimmune
malignancy - haematological, metastatic
sarcoid
What is lymphangitis?
red lines extending from an inflammed region showing regional lymphadenopathy
What does a predominant B cell response indicate?
autoimmune conditions
infections
What does a predominant T cell response indicate?
viral infections
drugs - phenytoin
What does a predominant phagocytic response indicate?
draining a tumour site
What is the structure of the spleen?
parenchyma has red pulp and white pulp
What is the role of the red pulp of the spleen?
ACTS AS A FILTER FOR BLOOD
sinusoids that are fenestraited and lined by endothelial cells and supported by hoops of reticulin
rods that contain macrophages and some fibroblasts and cells in transit
What is the role of the white pulp in the spleen?
lymphoid tissue so part of the immune response
consists of periarteriolar lymphoid sheath (PALS) - CD4 and lymphoid cells
apcs in white pulp present antigens to the immune reactive cells, then T and C cell responses may occur
What are the features of splenomegaly?
dragging sensation in RUQ
discomfort when eating
pain if infarction
hypersplenism
What is the hypersplenism triad?
splenomegaly
fall in one or more cellular components of blood
correction of cytopenias by splenomegaly
How is hypersplenism treated?
splenectomy
What can cause hyposplenism?
splenectomy coeliac disease sickle cell disease sarcoidosis iatrogenic
What are the features of hyposplenism?
reduced red pulp function:
Howell-Jolly bodies
RBC abnormalities
How does a viral lump present?
tender
hard
smooth
How does a bacterial lump present?
tender
hard
smooth
inflamed
How does a lymphoma present?
non tender
rubbery/soft
smooth
How does a metastatic carcinoma present?
non tender
hard
irregular
tethered
