Lymphatic System Flashcards
Functions
Drainage of interstitial fluid
Transporting dietary lipids and lipid soluble vitamins
Facilitation of the immune system
Hydrostatic pressure
The pushing force exerted by a fluid
30-10 mmHg between arterial and venous ends
Interstitial fluid pressure
Contributes to the outward pull of fluid from the capillaries
Proposed to be slightly negative
-3 mmHg
Colloidal somatic pressure
The pulling force created by blood proteins that are too large to pass through the pores of the membrane
28 mmHg in the capillaries
Interstitial osmotic pressure
8 mmHg
Creates by small number of plasma proteins that have leaked into the extracellular tissue space
Formation of lymph
Hydrostatic pressure pushes blood plasma out of capillaries to tissues
Plasma = interstitial fluid
Albumin is too large to leave the capillaries so creates osmotic pressure
This pulls the interstitial fluid back into capillaries
Not all fluid returns = lymph
Lymph into lymphatic capillaries
Lymphatic capillaries are blind ended
Initially have a lower pressure then interstitial fluid
Fluid enters via mini valves
Drainage of lymph
Lymph capillaries join to form lymph veins
Two ducts - right lymphatic duct and left thoracic duct
In small intestine they’re known as Lacteals - fat laden lymph; Chyle. Drain into Cisterna chyli
Right lymphatic duct
Drains the upper right side of the body and right arm
Returns lymph to the right subclavian vein
Left thoracic duct
Drains the rest of the body
Begins with the cisterna chyli and returns lymph to the left subclavian vein
Oedema
Palpable swelling produced by an increase in interstitial fluid volume
2.5-3L
Lymph nodes
Found along lymph vessels
Bean shaped
Afferent and efferent vessels
Filter lymph
Connective tissue capsule
Trabeculae project inwards to form compartments
Reticular cells - phagocytise unwanted substances
Lymphocytes - antibodies
Lymph nodes
Found along lymph vessels
Bean shaped
Afferent and efferent vessels
Filter lymph
Connective tissue capsule
Trabeculae project inwards to form compartments
Reticular cells - phagocytise unwanted substances
Lymphocytes - antibodies
Lymph nodules - Peyer’s patches
In areas exposed to the outside world
In mucosa of other tubular structures in the respiratory, urinary and reproductive systems
MALT - mucosa, associated, lymphoid, tissue
Tonsils
Surround the opening to the respiratory and digestive tracts
Filter air
2 x palatine - either side of the oral cavity
2 x lingual - at the base of the tongue
1 x pharyngeal or adenoids - on the posterior wall or the nasopharynx
