Scientists Involved with the Digestive System
Ivan Pavlov
Russian scientist Ivan Pavlov was born in 1849 in Ryazan, 1n 1870 Pavlov went into science. He made a great impact on physiology by studying the mechanisms underlying the digestive system in mammals.
Ivan Pavlov worked to unveil the secrets of the digestive system, but he also studied what signals triggered phenomena, such as the secretion of saliva. When a dog sees food, saliva starts to pour out from the salivary glands in the back of its oral cavity. To make food easier to swallow, this saliva is needed. The fluid also contains enzymes that break down certain compounds in food. In humans saliva contains the enzyme amylase, an effective processor of starch.
Pavlov became interested in reflexes when he saw that dogs drool without proper stimulus. Even when no food was in sight, their saliva still dribbled. Actually, the dogs were reacting to lab coats. Every time dogs were served food, it was from a person in a lab coat. Therefore, the dogs reacted as if food was coming when they saw a lab coat.
After this, Pavlov tried to see how this and phenomena were linked. In one of these experiments, he struck a bell when the dogs were fed. If the bell was sounded near their meal time, the dogs learned to associate the bell with the food. After a while, at the sound of the bell the dogs responded by drooling.
Ivan Pavlov worked to unveil the secrets of the digestive system, but he also studied what signals triggered phenomena, such as the secretion of saliva. When a dog sees food, saliva starts to pour out from the salivary glands in the back of its oral cavity. To make food easier to swallow, this saliva is needed. The fluid also contains enzymes that break down certain compounds in food. In humans saliva contains the enzyme amylase, an effective processor of starch.
Pavlov became interested in reflexes when he saw that dogs drool without proper stimulus. Even when no food was in sight, their saliva still dribbled. Actually, the dogs were reacting to lab coats. Every time dogs were served food, it was from a person in a lab coat. Therefore, the dogs reacted as if food was coming when they saw a lab coat.
After this, Pavlov tried to see how this and phenomena were linked. In one of these experiments, he struck a bell when the dogs were fed. If the bell was sounded near their meal time, the dogs learned to associate the bell with the food. After a while, at the sound of the bell the dogs responded by drooling.
Erasistratus
Philosopher, Erasistratus pointed out that after food was eaten, many things go on in the stomach and intestines. Since he could hear and feel different sounds, it suggested to him that digestion was a mechanical process.
Galen
Famous physician, Galen agreed that the liver was a huge organ in the process of digestion, but he felt the Hippocratics were right, animal heat must be a guiding force behind digestion.
Franciscus Sylvlus
In the 1700s, scientists started taking another look at the human body. Dutch physician, Franciscus Sylvlus believed that most body process are mostly chemical terms. Sylvius studied digestive secretions and concluded that digestion is a form of fermentation.
René de Réaumur
French physiologist René de Réaumur showed that the digestive chemicals play a huge role. De Réaumur fed a hawk two small metal cylinders filled with meat, then covered with gauze on the ends. The hawk regurgitated them, and De Réaumur discovered that the meat could only be dissolved by chemicals. This shows that digestive secretions could digest meat outside of the body.
William Beaumont
In 1825, William Beaumont began a series of experiments that would make a big contribution to the understanding of digestion. Ten years after Beaumont joined the army, he treated a man who had been shot in the side. This bullet wound never fully closed, which left an inch-wide opening that led to his stomach. Beaumont could now observe how the stomach changed under varying conditions, also he could remove samples of gastric secretions. Constructing over 200 experiments, Beaumont provided the world with new information about gastric physiology and digestive process in living human beings.
Claude Bernard
French physiologist Claude Bernard began creating fake fistulas (openings inch-wide openings) in laboratory animals. "Using these openings, he verified that the small intestine was the major site of digestion and that pancreatic secretions were important digestive agents, particularly with regard to fat molecules."
