Final answer:
The majority of osmotically active compounds in plasma are proteins, particularly albumin, and electrolytes, such as sodium and chloride, both playing crucial roles in maintaining osmotic pressure within blood plasma.
Step-by-step explanation:
The two components that together represent the majority of osmotically active compounds in plasma are proteins and electrolytes. The proteins in plasma, particularly albumin, are crucial in maintaining osmotic pressure. Albumin serves as a transport vehicle for lipids and steroid hormones and contributes significantly to the osmotic pressure of blood by holding water inside the blood vessels.
Electrolytes, such as sodium (Na+) and chloride (Cl-), are also vital as they ionize in water and contribute to osmotic pressure. The meticulous regulation of these electrolyte concentrations is essential for maintaining proper fluid balance across the body's fluid compartments, including blood plasma, extracellular fluid, and intracellular fluid.