Final answer:
Hepatocytes secrete about one liter of bile each day, which is a mixture of water, bile salts, bile pigments, phospholipids, electrolytes, cholesterol, and triglycerides. Bile salts and phospholipids play a critical role in emulsifying fats and increasing the surface area for lipid digestion.
Step-by-step explanation:
Hepatocytes secrete about one liter of bile each day. A yellow-brown or yellow-green alkaline solution (pH 7.6 to 8.6), bile is a mixture of water, bile salts, bile pigments, phospholipids (such as lecithin), electrolytes, cholesterol, and triglycerides. The components most critical to emulsification are bile salts and phospholipids, which have a nonpolar (hydrophobic) region as well as a polar (hydrophilic) region.
The hydrophobic region interacts with the large lipid molecules, whereas the hydrophilic region interacts with the watery chyme in the intestine. This results in the large lipid globules being pulled apart into many tiny lipid fragments of about 1 µm in diameter. This change dramatically increases the surface area available for lipid-digesting enzyme activity.