S9 Lymphatics Flashcards
What is the order of movement through vessels in the lymphatic system from the cells to the vein?
cells to capillaries to trunks to ducts to vein
How is the lymph moved around the lymphatic system?
Lymph is propelled by compression by local veins and arteries (lymphagion).
Ducts and trunks have smooth muscle.
It’s a low pressure system
Where are lymphatics not found?
Brain
CNS
What is the role of the thymus?
The thymus carries out THYMIC CELL EDUCATION (stem cells activated to T cells which activate B cells).
Where is the thymus found and what happens to it as you get older?
The thymus is found between the lungs. It shrinks as you get older.
What do lymph nodes do and what do they look like?
They filter lymph (afferent and efferent lymphatic vessels).
Look like kidneys
Where are lots of lymph nodes found?
Groin
Neck
Armpit
(Think of areas that get infected easily)
What is the clinical name for enlarged lymph nodes?
Lymphadenopathy
What does the spleen contain?
Red pulp
White pulp
What does red pulp do?
Site of haematopoiesis - removal and destruction of old/damaged/abnormal erythrocytes and platelets and stores erythrocytes - filters RBC
What does the white pulp do?
Site of immune response - antigen presentation/activation and proliferation of B and T lymphocytes.
What is a splenectomy?
Removal of spleen.
You can live without your spleen - bone marrow and liver can carry out haematopoiesis. However increased infection risk by encapsulated bacteria.
What is splenomegaly?
Enlargement of the spleen due to infection (localised or systematic)
What is lymphoma?
Malignancy of lymphoid tissue
Two types: Hodgkin’s and Non-hodgkin’s.
How much lymph is produced each day?
3-4L (it is recycled)
Upper right of body…
Rest of body…
…lymph drains into right subclavian vein (or internal jugular vein)
…lymph drains into the left “ “ “
Where is the spleen?
Behind (inferior to) the stomach
What do the tonsils do?
Prevent ingress of pathogens through nasal/oral routes
What do tonsils and vermiform appendix have to increase SA?
Crypts
What cells are on the surface epithelia of tonsils? And what do they do?
Microfold cells - present antigens to underlying immune cells
Why do tonsils swell?
Due to B and T cell proliferation
What is the type of tonsil we’re most interested in?
Palatine tonsil
What is in the lymph from the GI tract?
Chyle - white cloudy substance that contains fat and dissolved lipids.
What does the appendix do?
Prevents pathogen ingress from GI routes and ileum.
Name the lymphatic organs.
Tonsils, Thymus, Spleen, Vermiform Appendix, Lymph Nodes, Payer’s patches
Can you live without a appendix?
Yes, can be removed by appendectomy.
You aren’t immunocompromised when it is removed as rest of GI tract has lymph nodes and lymphoid tissue (GALT - gut associated lymphoid tissue).
What do Payer’s patches do?
Make T and B cells to fight infection in stomach and contain microfold cells to do so (present antigens to lymphocytes)
Where do you find Payer’s patches?
Side of ileum
What is the name of the 1st node that metastatic cancer develops?
Sentinel lymph nodes
What are primary and secondary lymphoedema?
Primary - congenital (e.g. milroy’s diease)
Secondary - due to medical intervention/immobility/parasites/infection (e.g. cellulitis - vessel obstruction)
How can sentinel lymph nodes be used in cancer detection?
First lymph nodes to swell.
Inject purple dye into this area and can see where cancer has spread to.
How do you treat lymphoedema?
There’s no cure, only improvement of symptoms.
Can use compression stockings
What are the four main functions of the lymphatic system?
- Fluid balance
- Transport of fats and fat-soluble vitamins (from digestive system to venous circulation)
- Defence against pathogens and disease
- Storage and destruction of aged erythrocytes (spleen)
What are germinal centres?
Sites at which mature B cells proliferate.
Dendritic cells attract helper T cells which activate B cells which proliferate at germinal centres.
What are dendritic cells?
Antigen presenting cells
