Lymphatic Vessels
Lymphatic Vessel Histology
Key points:
- Collect interstitial fluid, carry it to lymph nodes, and ultimately return it to systemic circulation via the thoracic ducts.
- Interstitial fluid comprises blood plasma, white blood cells, and other elements.
- Have multiple layers of smooth muscle that contract to propel the lymph.
- Larger lymph vessels have valves which that unidirectional flow of lymphatic fluid by preventing backflow.
- Valves arise from the tunica intima to promote unidirectional flow.
- Anchoring filaments attach the vessel to surrounding interstitium.
- Interstitial lymph enters through the openings in the vessel wall
Clinical Correlations:
- Because the valves prevent backflow, lymph fluid travels unidrectionally. If the valves fail, lymph fluid pools and causes lymphedema (as with varicose veins, this is particularly relevant in the extremities).
- Cancer cells can break from a tumor and travel within the lymph vessels;