What happens to the lower part of the stomach that is bypassed in the Gastric Bypass Procedure?
With the Roux-en-Y gastric bypass, the stomach is left in place with intact blood supply. It may shrink a bit and its lining (the mucosa) may atrophy (become smaller), but for the most part it remains unchanged. The lower stomach still contributes to the function of the intestines even though it does not receive or process food – it makes intrinsic factor and gastric juices, necessary to absorb Vitamin B12 and contributes to hormone balance and motility of the intestines in ways that are not entirely known.