Master Foregut Structures, Blood Supply and Innervation Anatomy

The foregut gives rise to the esophagus, a tubular structure that serves as a passage for food to enter the stomach.

The respiratory bud forms out of the developing esophagus. It later becomes the components of the lower respiratory tract (e.g. alveoli, bronchioles, etc.)

The stomach is situated between the lower esophagus and proximal duodenum. It helps to break down several macromolecules in preparation for absorption.

The foregut gives rise to the parts 1 and 2 of the duodenum up to the ampulla of Vater. The rest of the duodenum (parts 3 and 4) are derived from the midgut.

The liver is a foregut structure. It serves multiple important functions involved in metabolism, such as processing various metabolites and eliminating toxins, storing excess glucose as glycogen and maintaining blood glucose during fasting, and production of bile acids.

The gallbladder is a foregut structure. Its primary function is to store bile, a mixture of bilirubin and bile salts which aid in digestion, and release it following meals.

The pancreas develops as ventral and dorsal pancreatic buds from the duodenum. It has several important endocrine as well as exocrine functions.

The spleen is technically not a foregut structure since it is derived from mesoderm instead of endoderm. However, it is included here as it derives most of its blood supply from the celiac artery trunk (via the splenic artery). The spleen serves important hematological and immunological roles.

Blood supply to the foregut is supplied mainly by the celiac artery, which is branches off the aorta. The other two arteries that supply the gut are the superior mesenteric artery (for the midgut) and inferior mesenteric artery (for the hindgut).

The vagus nerve (CN X) innervates the foregut structures. It provides parasympathetic innervation to foregut structures, as well as various other tissues and glands throughout the body.