Lymph and plasma are both bodily fluids, but they differ significantly in composition and function. Plasma is the liquid component of blood, while lymph is a fluid derived from plasma that circulates through the lymphatic system.
Key Differences Between Lymph and Plasma
| Feature | Plasma | Lymph |
|---|---|---|
| Appearance | Straw-colored, clear | Colorless, sometimes milky |
| Protein Content | High | Low |
| Location | Blood vessels | Lymphatic vessels |
| Function | Transports nutrients, hormones, etc. | Transports immune cells, waste products |
| Origin | Directly from the blood | From interstitial fluid, a filtrate of blood plasma that leaves capillaries |
| Calcium & Phosphorus | Higher concentrations | Lower concentrations |
Compositional Differences:
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Protein Levels: Plasma is protein-rich, while lymph is relatively protein-poor. This is because many of the proteins in plasma are retained in the blood vessels, and smaller proteins and waste products permeate through the capillary walls into the interstitial fluid and then lymph. Studies like this one highlight differences in protein profiles between lymph and plasma, visible through techniques like FPLC and 2D gel electrophoresis.
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Mineral Differences: As noted by Byjus, plasma generally has higher concentrations of calcium and phosphorus than lymph.
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Waste Products: Lymph carries waste products away from tissues, while the primary function of plasma is nutrient and hormone transport.
Functional Differences:
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Immune Function: Lymph plays a crucial role in the immune system, transporting immune cells like lymphocytes to and from lymph nodes, where they filter pathogens and other foreign substances. Plasma, being part of the blood, is involved in transporting immune cells but is not the primary fluid for their trafficking and filtration.
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Fluid Balance: Plasma maintains blood volume and pressure. Lymph collects excess interstitial fluid and returns it to the bloodstream, helping to maintain fluid balance throughout the body, as explained by Cleveland Clinic.
While some studies (https://bioone.org/journals/journal-of-herpetological-medicine-and-surgery/volume-32/issue-1/JHMS-D-20-00017/Comparison-of-Biochemistry-Values-from-Plasma-and-Lymph-in-Kreffts/10.5818/JHMS-D-20-00017.full) might show insignificant differences in certain parameters between lymph and plasma in specific contexts, the overall differences in composition and function remain significant.
