Final answer:
Albumin is an expensive colloid that rapidly expands plasma volume due to its osmotic properties as the most abundant plasma protein. Isotonic solutions like saline are used in dehydration to prevent cellular injury due to osmotic imbalances.
Step-by-step explanation:
The colloid that is expensive but rapidly expands plasma volume is Albumin. This is due to the fact that albumin is the most abundant plasma protein in the human body, and it has a significant osmotic effect, which means it is effective at holding water within the blood vessels, thereby expanding plasma volume. Ensuring the intravenous solutions like normal saline and lactated Ringer's solution are isotonic is crucial because this similarity to body fluids prevents the passage of water in or out of the body's cells which could lead to cellular swelling or shrinkage.
Regarding the true statement about albumin, the correct answer is b. It is the most abundant plasma protein. Albumin is primarily produced by the liver, not specialized leukocytes, and it works to retain water within the blood vessels rather than drawing it out into the tissues.
When treating dehydration, the typical intravenous solution provided to a human patient is saline at a concentration that is isotonic with respect to body fluids, which replenishes electrolytes balance and ensures no further cellular injury due to osmotic imbalances.