Lymph nodes Flashcards
What are lymph nodes?
Lymph nodes are secondary/peripheral lymphoid structures
They are ovoid, encapsulated collections of lymphoid tissue
What are the main primary lymphoid structures?
Bone marrow
Thymus
What are the main secondary lymphoid structures?
Lymph nodes
Tonsils
Spleen
Peyer’s patches
What are the 2 classes of node group location?
- Superficial
- Internal
Lymph drainage of the neck and lower face (Image)
Lymph drainage of the axilla (Image)
Lymph drainage of the inguinal region (Image)
Lymph drainage of the abdominal aorta and pelvic organs (Image)
What structure surrounds the lymph node?
Connective tissue capsule
Describe the movement of lymph through the lymph node
Afferent lymphatics ->
Sub-capsular sinus ->
Trabecular sinus ->
Medullary cords and sinuses ->
Hilum ->
Efferent lymphatics
What is the advantage of cell traffic within lymph nodes?
Cell traffic provides interactions for immune responses, allowing antigenic material to interact with fixed lymphoid tissue
What are the 3 main regions of the lymph node?
Cortex
Paracortex
Medulla
Describe the structure of the lymph node cortex
Nodules of B lymphocytes arranged in follicles
Describe the structure of the lymph node paracortex
Mainly contains T lymphocytes, forming inter-follicular tissue which surrounds follicles and extends out and merges with the medulla
Describe the structure of the lymph node medulla
Cords and sinuses draining into hilum
The medulla contains:
- Blood vessels
- Sinuses
- Medullary cords
- Medullary sinuses
What are the 2 classes of follicles within the lymph nodes?
Primary
Secondary
Describe the structure and function of pimrary follicles
Primary follicles have no germinal centre, and contain small quiescent lymphocytes which are yet to be stimulated
Describe the structure and function of secondary follicles
Secondary follicles contain a germinal centre in which B cells form their final form
These are active follicles, reacting to a stimulus
What is contained in medullary cords?
Plasma cells
B cells
Macrophages
What is contained in medullary sinuses?
Histiocytes
Reticular cells
What types of cells are present in lymph nodes?
Lymphocytes
Macrophages
APCs
Dendritic cells
Endothelial cells
What are some B cells present in the follicles of lymph nodes?
- Follicle centre cells
- Mantle cells
- Marginal cells
- Plasma cells
What are some B cells found between follicles in the lymph nodes?
- Post-germinal centre B cells
- Plasma cells
What is lymphadenopathy?
Lymphadenopathy is lymph node enlargement
What are some descriptions of location of lymphadenopathy?
Localised/Generalised
Peripheral/Central
What are some causes of lymphadenopathy?
Local inflammation
Systemic inflammation
Malignancy
Genetic or systemic disease
What are some possible causes of local inflammation in lymphadenopathy?
- Infection
- Vaccination
- Dermatopathic