Final answer:
A barium sulfate suspension is used to demonstrate the esophagus, pylorus, and ileum in the gastrointestinal tract during x-ray imaging, because it coats the lining and is opaque to x-rays.
Step-by-step explanation:
A patient is usually required to drink a barium sulfate suspension to demonstrate various structures of the digestive system during medical imaging procedures. When ingested, this suspension, sometimes referred to as a "barium milkshake," coats the lining of the gastrointestinal tract. This high atomic mass of barium makes it opaque to x-rays, allowing for the detailed visualization of structural abnormalities or issues within the digestive organs.
The barium sulfate suspension particularly helps in demonstrating the esophagus, the stomach including the pylorus, and various parts of the small and large intestine, such as the ileum. It is a valuable tool in the diagnosis of various conditions like acid reflux disease, Crohn's disease, and ulcers. Since the Ksp (solubility product constant) for barium sulfate is very low, indicating it is highly insoluble, the risk of absorption into tissues and subsequent toxicity is minimal. Hence, it safely provides an outline of the digestive organs on x-rays without being absorbed.
In response to the specific question, a barium sulfate suspension is used to demonstrate the esophagus, pylorus (part of the stomach), and the ileum among other parts of the intestine.