Title: Chyme
Content:  After hours of mechanical and chemical digestion, food has been reduced into chyme. As particles of food become small enough, they are passed out of the stomach at regular intervals into the small intestine, which stimulates the pancreas to release fluid containing a high concentration of bicarbonate. This fluid neutralizes the gastric juices, which can damage the lining of the intestine and result in duodenal ulcer. Other secretions from the pancreas, gallbladder, liver, and glands in the intestinal wall help in digestion. When food particles are sufficiently reduced in size and composition, they are absorbed by the intestinal wall and transported to the bloodstream. Some food material is passed from the small intestine to the large intestine. In the large intestine, bacteria break down any proteins and starches in chyme that were not digested fully in the small intestine. When all of the nutrients have been absorbed from chyme, the remaining waste material changes into semisolids that are called feces. The feces pass to the rectum, to be stored until ready to be discharged from the body during defecation.
Title: Chyme
Content:  Chyme or chymus (from Greek χυμός khymos, "juice" ) is the semi-fluid mass of partly digested food that is expelled by a person's stomach, through the pyloric valve, into the duodenum (the beginning of the small intestine). Chyme results from the mechanical and chemical breakdown of a bolus and consists of partially digested food, water, hydrochloric acid, and various digestive enzymes. Chyme slowly passes through the pyloric sphincter and into the duodenum, where the extraction of nutrients begins. Depending on the quantity and contents of the meal, the stomach will digest the food into chyme in some time from 40 
Title: Small intestine
Content:  Food from the stomach is allowed into the duodenum through the pylorus by a muscle called the pyloric sphincter.
Title: Peristalsis
Content:  Once processed and digested by the stomach, the semifluid chyme is passed through the pyloric sphincter into the small intestine. Once past the stomach, a typical peristaltic wave lasts only a few seconds, travelling at only a few centimeters per second. Its primary purpose is to mix the chyme in the intestine rather than to move it forward in the intestine. Through this process of mixing and continued digestion and absorption of nutrients, the chyme gradually works its way through the small intestine to the large intestine. In contrast to peristalsis, segmentation contractions result in that churning and mixing without pushing materials further down the digestive tract.
Title: Chyme
Content:  Chyme has a low pH that is countered by the production of bile, helping to further digest food. Chyme is part liquid and part solid: a thick semifluid mass of partially digested food and digestive secretions that is formed in the stomach and small intestine during digestion. Chyme also contains cells from the mouth and esophagus that slough off from the mechanical action of chewing and swallowing.
Title: Human digestive system
Content:  from the pancreatic duct and also from secretions of bicarbonate-rich mucus from duodenal glands known as Brunner's glands. The chyme arrives in the intestines having been released from the stomach through the opening of the pyloric sphincter. The resulting alkaline fluid mix neutralises the gastric acid which would damage the lining of the intestine. The mucus component lubricates the walls of the intestine. When the digested food particles are reduced enough in size and composition, they can be absorbed by the intestinal wall and carried to the bloodstream. The first receptacle for this chyme is the duodenal bulb. From here 
Title: Chyme
Content:  through the jejunum and the ileum, where digestion progresses, and the nonuseful portion continues onward into the large intestine. The duodenum is protected by a thick layer of mucus and the neutralizing actions of the sodium bicarbonate and bile. At a pH of 7, the enzymes that were present from the stomach are no longer active. This then leads into the further breakdown of the nutrients still present by anaerobic bacteria, which at the same time help to package the remains. These bacteria also help synthesize vitamin B and vitamin K, which will be absorbed along with other nutrients.
Title: Peristalsis
Content:  When a peristaltic wave reaches at the end of the oesophagus, the cardiac sphincter (gastroesophageal sphincter) opens allowing the passage of bolus into the stomach. Gastroesophageal sphincter normally remains closed and does not allow food contents of the stomach to move back. The churning movements of stomach's thick muscular wall mixes the food thoroughly with the acidic gastric juice and is called the chyme. The muscularis layer of the stomach is thickest and maximum peristalsis occurs here. After short intervals, the pyloric sphincter keeps on opening and closing so the chyme is fed into the intestine in installments.
Title: Digestion
Content:  occurring, mechanical mixing occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with the digestive enzymes. Pepsin breakdowns proteins into peptides or proteoses, which is further broken down into dipeptides and amino acids by enzymes in small intestine. Studies suggest that increasing the number of chews per bite increases relevant gut hormones and may decrease self-reported hunger and food intake. After some time (typically 1–2 hours in humans, 4–6 hours in dogs, 3–4 hours in house cats), the resulting thick liquid is called chyme. When the pyloric sphincter valve opens, chyme enters the duodenum where it mixes 
Title: Human digestive system
Content:  degree though is not as efficient as the pancreatic lipase. The pylorus, the lowest section of the stomach which attaches to the duodenum via the pyloric canal, contains countless glands which secrete digestive enzymes including gastrin. After an hour or two, a thick semi-liquid called chyme is produced. When the pyloric sphincter, or valve opens, chyme enters the duodenum where it mixes further with digestive enzymes from the pancreas, and then passes through the small intestine, where digestion continues. The parietal cells in the fundus of the stomach, produce a glycoprotein called intrinsic factor which is essential for the absorption of vitamin B12. Vitamin B12 (cobalamin), is carried to, and 

Question: what allows chyme to enter the small intestine?
Answer: pyloric valve.
the pyloric valve.