Lymph or tissue fluid is formed when plasma, proteins, and blood cells escape through capillary walls into intercellular spaces. It serves as a colorless fluid similar to blood plasma, with fewer proteins. Lymph drains excess fluid and carries digested fats ...

Platelet cells circulate in the blood to plug leaks in the circulatory system, helping to clot blood at points of injury. This response minimizes blood loss and maintains the efficiency of the pumping system.

Capillaries, with walls one-cell thick, allow for efficient exchange of materials between the blood and surrounding cells. This thin barrier facilitates the diffusion of substances like oxygen and nutrients into tissues and the removal of waste products.

Veins have thinner walls compared to arteries as they carry blood back to the heart at lower pressure. Veins have valves to ensure one-directional blood flow, preventing backflow.

Arteries have thick, elastic walls because they carry blood away from the heart under high pressure, helping to withstand and accommodate the force generated by the pumping action of the heart.