L E A R N IN G O U TC O M E S• Explain how the lymphatic system complements the circulatory system;• Compare the content of blood, interstitial fluid & lymph;• Predict what will happen if interstitial fluid fails to return to the circulatory system;• Conceptualise the relationship between the lymphatic system & circulatory system.
THE LYMPHATIC SYSTEMCOMPLEMENT THE CIRCULATORY SYSTEM• 10% of interstitial fluid drains into the lymphatic capillaries forming lymph.• Move due to the contraction & relaxation of skeletal muscles backflow is prevented by semilunar valves.• Lymph in the right lymphatic duct & the thoracic duct flows into the right & left subclavian veins of the BCS, respectively.
COMPARE THE CONTENT OF BLOOD, INTERSTITIAL FLUID & LYMPH BLOOD INTERSTITIAL FLUID LYMPH DIFFERENCES Inside blood vessel In the intercellular Inside the lymphatic spaces vessels More protein than Less protein than More protein than interstitial fluid & blood & lymph interstitial fluid but less lymph than blood Oxygenated Oxygenated Deoxygenated Erythrocytes, Only leucocytes Only leucocytesleucocytes & platelets present present present Low lipid content Low lipid content High lipid content
If In t e r s t it ia l F lu id F a ils to R e turn to th C ir c u la t o r y S y s t e m• It accumulates in the organs & tissues the organs & tissues swell up oedema.• Interstitial fluid should return to the CS at the same rate as it is produced.
THE RELATIONSHIP BETWEEN LYMPHATIC SYSTEM & BLOOD CIRCULATORY SYSTEM• LS & BCS transport interstitial fluid back to the heart.• The LS joins the BCS when the right lymphatic duct opens into the right subclavian vein & the thoracic duct opens into the left subclavian veins.