The ileum is the final section of the small intestine, following the jejunum. It measures about 3 to 4 meters in length and plays a crucial role in the digestion and absorption of nutrients. The ileum is particularly important for absorbing vitamin B12 and bile salts, which are essential for fat digestion. Located in the lower right abdomen, the ileum connects to the cecum, the beginning of the large intestine. Its inner lining contains numerous villi and microvilli, which increase the surface area for absorption. Proper functioning of the ileum is vital for overall digestive health.