Final answer:
Short-chain fatty acids from fat digestion are absorbed directly into the bloodstream via simple diffusion, while larger lipid products need bile salts for emulsification before being absorbed into the lymphatic system and then the bloodstream.
Step-by-step explanation:
The absorption of larger and smaller products of fat digestion differ primarily in their mechanism of entry into the cells of the small intestine. Short-chain fatty acids, which are the smaller products, are water-soluble and can enter the absorptive cells (enterocytes) directly through simple diffusion. They then travel into the blood capillary of a villus alongside monosaccharides and amino acids. On the other hand, larger lipid digestion products require emulsification by bile salts to form micelles, which facilitate their absorption into the enterocytes. Once inside these cells, they are reassembled into triglycerides and packaged into chylomicrons, which enter the lymphatic system and eventually the bloodstream.