Module 4: Immune-Lymphatic System: The Lymph Nodes Flashcards
where are the majority of lymphocytes in the body
arranged into encapsulated, highly organized structures
Lymph Nodes!
3 functions of lymph nodes
Non specific filtration of lymph by phagocytic action of macrophages
Storage and proliferation of B lymphocytes
Storage and proliferation of T lymphocytes
How do cells produced then leave the lymph node
via efferent lymphatics
Lymph node shape
kidney shaped; variable sizes
Lymph node organ capsule
encapsulated by ease connective tissue
Trabeculae
extend from capsule for variable distances into the node
Provide support and conveyance of large blood vessels
Source of support for interior lymph node
network of fine reticular fibres
pathway of lymph through lymph node
lymph enters through afferent lymphatics
Into subcapsular sinus
Into medullary sinuses via cortical sinuses
Exits through hilum of node into efferent lymphatics
2 distinct zones of lymph node
cortex and medulla
Lymph node cortex
contains densely packed lymphocytes and forms extensions called medullary cords
Cords project into an inner medullary space
Within cortex, lymphs form into densely packed lymphoid follicles
Pale center areas or germinal centres are sites where proliferation of b lymphocytes occurs
Deep cortical zone or paracortex in Lymph node
area below follicles and just above the medulla
Mainly t lymphs which are NEVER arranged as follicles
Lymph node paracortical _______ in the case of cellular response
thickens
due to production of t lymphs
Result of lymph node during Humoral response
follicular stimulation and production of B lymphs
Lymph node medulla
extension of cortex project down forming “medullary cords”
Darker staining areas; aggregations of B lymphs and plasma cells (basophilia seen)
Wide, irregular medullary sinuses seen between cords
Blood vessels are supported of the lymph node
