Lymphatic capillaries are more permeable due to the presence of:

Lymphatic capillaries are specifically designed to facilitate the uptake of interstitial fluid, proteins, and even larger molecules, which is primarily made possible by the presence of minivalves. These structures act as one-way valves that open in response to increased fluid pressure in the tissue spaces. When interstitial fluid pressure rises, the minivalves open, allowing fluid to enter the lymphatic capillaries. Conversely, when the pressure inside the capillaries rises, the minivalves close to prevent backflow, ensuring that lymphatic fluid moves unidirectionally toward the larger lymphatic vessels and ultimately to the circulatory system.

This unique feature of lymphatic capillaries makes them significantly more permeable compared to blood capillaries, which lack this one-way valve mechanism. As interstitial fluid collects and pressure rises, the minivalves facilitate the efficient uptake of this fluid, playing a crucial role in maintaining fluid homeostasis and immune function. Understanding the importance of these minivalves helps clarify how lymphatic capillaries effectively contribute to the overall functioning of the lymphatic system.