The short upper section of the human intestine next to the stomach is called

The duodenum is the first and shortest section of the small intestine, approximately 25-30 cm long, connecting directly to the stomach at the pyloric sphincter. It receives partially digested food (chyme) from the stomach, along with bile from the liver and digestive enzymes from the pancreas. The caecum marks the beginning of the large intestine, while the ileum and jejunum are the middle and final sections of the small intestine, respectively. The duodenum's primary function is neutralizing stomach acid and continuing chemical digestion.