What do we call the plasma within blood vessels?

The plasma within blood vessels is referred to as intravascular plasma. This term specifically describes the liquid component of blood that circulates within the cardiovascular system, including arteries, veins, and capillaries. Intravascular plasma is crucial as it contains water, proteins, electrolytes, nutrients, hormones, and waste products that are essential for transporting these substances throughout the body.

The other options refer to different contexts or components in the body. For instance, interstitial fluid is the fluid that fills the spaces between cells in tissues, serving as a medium for nutrient and waste exchange. Intracellular fluid describes the fluid found within cells themselves, essential for cellular processes. Hypotonic refers to a solution with a lower concentration of solutes compared to another solution, which is a different concept that relates to osmotic pressure and cell behavior in various environments. Understanding these distinctions is important for grasping the terminology and concepts in physiology and nursing practice.