In this blog we are going to discuss Phase I- The Cephatic or Oral Phase - CHEWING!
Before food is even in sight, the brain prepares the body for digestion. The mere smell or thought of food can trigger a release of chemicals in the stomach.
Your mouth is your first digestion organ and the process continues through your esophagus, the stomach, small intestine, large intestine until is come out the other end.
The main job of digestion is to break down food materials into particles small enough that our body can utilize them so we can access the energy known as calories stored inside fats, proteins and carbs. Taking this further, fats, proteins & carbs need to be broken down into water soluble nutrients that can be absorbed through the intestinal wall. Food is basically digested through a long tube (hollow organ); as food travels down the tube it is broken down into its smallest form.
A monomer is a molecule that can bond to another molecule and form a chain. A polymer is a chain of molecules in food (fats, proteins, carbs). Our digestion breaks down these polymer chains so they can be absorbed into the intestinal lining so they can build new chains.
The goal of digestion is to breakdown polymers into monomers so the body can build its own polymers.
The digestive tube that runs from the mouth to the anus is called our Alimentary Canal. We assume this canal is located inside our body because we can't see it, but its technically outside the body. Did you know your digestive tube is exposed to the outside world meaning not only can food enter but so can anything else?
That's why our tubes are coated with epithelial cells which are cells that serve as a barrier for every part of our body exposed to the outside world.
The entire digestion process takes anywhere from 24-72 hours but varies from person to person. The different rates of digestion could be based on the foods we eat & whether we are stressed or calm.
In Phase I, the "chewing" phase, on average, the mouth produces up to 1.5 quarts of saliva a day and our entire DNA blueprint in found in our saliva.
Saliva is 98% water but it also contains antibacterial components, electrolytes and mucous. Mucous coats the food for safe travel. That is why a potato chip doesn't scratch your windpipe on the way down.
Chewing food in our mouths also activates our salivary gland to secrete our first digestive enzyme. An enzyme that begins to breakdown starch or carbs.
When the food is fully coated with mucous, it has a watery consistency and is in smaller pieces, it is ready to travel down the esophagus or food pipe. Once food is properly mashed up in the mouth it passes through the Pharynx which is part of the throat that does the swallowing and at this point if getting technical, we no longer call it food, we call it bolus (partially digested food).
As bolus heads toward the Pharynx down the esophagus there is a valve that blocks any liquid from going up the nose or down the air tube. The esophagus is about 8 inches long and is made up of mucous lining tissue. Your bolus, partially digested food, travels down the esophagus via a method called Peristalsis.
Peristalsis is a series of wave-like motions that push the food forward through contractions. Because its involuntary it means that food will keep going even if we get distracted. In fact, this motion is so strong that if you were standing upside down it would defy gravity and keep going.
As the bolus enters the stomach from the esophagus, we enter Phase II of digestion, The Gastric Phase.
....to be continued...