Question

Short / Long type answer type question.

Why does the lymph contain much less proteins than the plasma?

Answer 1

• The hydrostatic pressure inside the blood capillaries is greater than that in the tissues, pushing fluid out. The fluid that leaks out into the interstices among the cells is a little of the watery part of the blood plasma, with all the substances it contains except for the larger proteins.
  
• Also, a very small fraction of the plasma proteins escape from blood capillaries in the tissues.
  
• Hence, lymph contains less proteins than blood plasma. Lymph contains relatively less of the larger proteins compared to plasma suggesting that molecular size is important in lymph filtration.