The Lymphatic System Flashcards
What is lymph?
Fluid and plasma proteins.
Lymphocytes are gained in lymphatic capillaries and channels.
Absorbed fats from the SI (drained into the SVC, and moved to the liver for absorption).
What is lymph flow?
Relies on contractions, pressure, and gravity.
Valves promote unidirectional flow.
Fluid flowing into extracellular spaces increases during infection (via osmosis). Lymph flow increases as more antigens are presented.
What are the drainage routes of lymph?
Initially symmetrical from the limbs, head, neck and trunk. Deep lymphatic drainage follows routes of arterial supply.
Where does lymph congregate?
The right lymphatic duct.
The thoracic duct - below the diaphragm and left side of the body.
These empty into the venous system at the jugular/subclavian junction.
What is the thoracic duct?
Starts at L1 as the cisterna chyli.
Ascends on vertebral bodies, between the azygos vein and the aorta, on the right of the posterior thoracic wall (below T4).
At T4 - crosses to the left and drains into the medial end of the left subclavian vein.
What are lymphoid tissues?
Structures where lymphocytes are generated and mature.
Thymus, bone marrow, spleen, lymph nodes.
What is the spleen?
The largest lymphatic organ.
In the upper left quadrant of the abdomen.
Contains a lot of blood (discharged via smooth muscle action).
Made of red pulp and white pulp (similar histology to a lymph node).
What are lymph nodes?
The locations of immunological function for lymph. Can be isolated, or grouped (at the bases of major arterial trunks).
What are deep lymph nodes chiefly associated with?
Mesenteries - a fold of the peritoneum that attaches the stomach, SI, pancreas and spleen to the posterior wall of the abdomen.
What are lymph nodes often the site of?
Primary tumours (lymphomas).
Secondary tumours occur as a result of metastasis from these sites. Infections spread through the lymphatic system, which can cause inflammatory hyperplasia of lymph nodes.
