Question

What does the fluid connective tissue consists of?

Answer 1

Some connective tissues of the body are fluids. Although it can be difficult to visualize fluids as "connective" components, an examination of their roles in body homeostasis provides insight into why they are considered tissues of this type. It might be better to think of fluid connective tissues as providing "physiological" rather than physical connections between tissues.
Blood and lymph are two extremely important fluids involved in transport and body defense. Most of us are familiar with blood and its transport roles in the body. We recognize that blood carries nutrients and oxygen to tissue cells and carries wastes from these cells to the lungs or kidneys for elimination. On the other hand, few of us recognize critical links between blood and lymph fluids in tissue spaces and the specific role of lymph in body homeostasis. Review the events of inflammation induced by histamine and other agents. This is central to understanding lymph and its role in body homeostasis.
Now, envision blood sweeping through vessels into tissues. As this blood enters the tiny, branching, thin-walled capillaries, fluid pressures cause plasma to leak across capillary walls into tissue spaces. The analogy here is a hose with tiny holes! If you run fluid through the hose, some fluid leaks out. If you increase flow through the hose, more fluid leaks out!

The fluid components of plasma that leak into interstitial spaces across capillary walls form interstitial fluids. Interstitial fluids are important in a physiological sense in that solutes and respiratory gases(i.e. oxygen, glucose) of the blood diffuse across these fluids to body cells. The waste products that accumulate within active cells also diffuse in the opposite direction across these fluids, from cells to capillaries. Some of this formed interstitial fluid returns to the blood, leaking back across capillary walls from interstitial spaces. Remaining fluid drains off through nearby lymphatic vessels. Subsequently, lymphatic capillaries and vessels are best described as a drainage/filtration system for tissue spaces. Under normal conditions, a balance exists with no excess fluid accumulating in tissues. Lymph draining from interstitial spaces eventually returns to the venous vascular flow.