Lymphatic system Flashcards
What are the 4 primary functions of the lymphatic system?
Tissue drainage
Return of plasma and plasma proteins
Transport of absorbed fat from the gut
Immunity
Why is lymph needed for drainage of interstitial fluid, and capillaries are not utilised?
Capillary venules do not allow re-entry of fluid, whereas the lymphatic capillaries have overlapping endothelial cells, that allow this
Aside from lymph fluid and plasma proteins, what can be found in lymph capillaries?
Lymphocytes
Fats
What structural feature in the lymphatic ensures unidirectional flow?
Valves
Describe how infection leads to increased flow throw the lymphatic system, and a greater immune response at the lymph nodes.
Infection means an accumulation of proteins in the extracellular space
Fluid flows into these spaces via osmosis
More extracellular fluid = more flow into lymph
More antigens in lymph = more presented in the nodes = more phagocytosis
What is secondary lymphoid tissue?
Lymph nodes
Where are most lymph nodes found grouped together?
At the bases of major arterial trunks
Describe the structure of a lymph node.
Mass of lymphatic tissue surrounded by fibrous capsule
Contains trabeculae and follicles (germinal centres)
Each node has afferent and efferent lymphatic vessels
Each node has it’s own blood supply (vein and artery)
Capillaries innervate the tissue
Where are most lymphocytes found in lymph nodes?
Germinal centres - follicles in the lymphoid tissue of the node
Give the 3 palpable areas of lymph nodes.
Axillary
Inguinal
Cervical
What are sentinal nodes?
The first few nodes that drain an organ/tumour
What type of tumours can lymph nodes get:
Primary or secondary?
Both
primary - lymphomas
secondary - metastasis from other sites
What happens to the lymph nodes in inflammatory hyperplasia?
They become enlarged
Aside from cancer and Inflam. hyperplasia, what other pathologies can happen to lymph nodes?
Glandular fever and tuberculosis
All lymphatic drainage ends up in two drainage routes. What are these called?
Thoracic duct - (main)
Right lymphatic duct - (right side of head, right arm, right peck and surrounding areas)
What is highly concentrated in lymph fluid when it returns from the small intestine?
Fats absorbed from our food
Into lacteals
Where does the fat absorbed into the lymph go?
Superior vena cava
Then to the liver
What is the largest organ that is directly involved with the lymphatic system?
Spleen
The histology of the spleen looks similar to another structure in the body. What is it, and how are they similar?
Similar to lymph nodes
Germinal centres have high concentrations of lymphocytes (in LN). In the spleen, white pulp areas have high concentrations of lymphocytes also.
What is the anatomical difference between para-aortic and pre-aortic lymph vessels?
Pre-aortic - anterior to aorta
Para-aortic - posterior to aorta
What are the only organs/tissues in the body without lymphatic drainage?
Cartilage, the eyes, inner ear, brain and spinal cord
