Understanding Digestive System Physiology

digestive_systemThe digestive system is critical for the intake of whole food and converting it into energy and nutrients that the body will need to function, heal and grow over time. There are six stages that are included in the digestive system. These stages include:

  • The mouth ingest food
  • Salvia, among of fluids enzymes starts to break down and start the digestive process
  • The body begins to move and mix food through the body to extract nutrients and extract waste.
  • The digestive process move food into smaller pieces
  • The body then absorbs these nutrients
  • The body will begin the excrete waste.

Ingestion Process

The first part of the digestive system is the ingestion of food through the mouth. The mouth is responsible ingestion and taking in food. The mouth is the orifice for all food to enter. The mouth and stomach are also responsible for storing food. The storage capacity of the stomach allows more food to be ingested while the food sets in the stomach for digestion. Due to the storage capacity of the stomach, the body can eat only a few times a day,  and to take in more than it can digested at any given time.

The Body also secretes fluid to help digestion.

The body secretes about 7 liters of fluid each day, These fluids include, salvia, mucus, hydrochloric acid, enzymes and  bile.  Inside Salvia salivary amylase helps moisten  and digest dry foods. The mucus that is secreted helps protect and lubricate inside the gastrointestinal track. The Hydrochloric acid will help digest food chemicals and protects the body from bacteria that is present in the food. The enzymes in these fluids help break down large macromolecules, such as lipids, proteins and carbohydrates into small portions. The Bile will emulsify these lipids into small globules for digestion.

Mixing and Moving in the Digestive System

digestiveThere are three main process that happen when food is moved and mixed in the digestive system.

  • During the Swallowing process, The smooth and skeletal muscles in the mouth, tongue and pharynx, will push the food down from the mouth and pharynx into the esophagus.
  • The Peristalsis, which is a muscular wave  that will travel throughout the length of the GI tract. The peristalsis moves to the partly digested food  down the tract.  It will take many waves of peristalsis to move food from the esophagus to the stomach and intestines to the end of the GI tract.
  •  The last is a segmentation. Segmentation will happen only when a intestine contract and squeezes food. Segmentation will increase the absorption by increasing the contact food have with the walls of the intestine

Digestion Process

The digestive process breaks down food into chemical components. Mechanical digestion is the physical  process of breaking down large pieces of food into smaller pieces. The digestion will start when the body begins chewing food with teeth and will continue to mix food in the stomach and intestines. Bile is created inside the liver to mechanically break fats into smaller globules. While this mechanically process happens,  the chemical process of larger molecules to smaller molecules. This will make the absorption process easier. The chemicals within digestion begins to work when the mouth secretes salivary amylase in saliva, which can breakdown complex carbohydrates into simpler carbohydrates. The enzymes and stomach acids will continue the chemical digestion process. The buck of the chemical digestion will take place ins the small intestine from the pancreatic juice, which is a combination of chemicals that digest lipids, proteins, carbohydrates and nucleic acids. When to food is processed through duodenum, it is now chemical combination of amino acids, monosaccharides and nucleotides.

Absorption Process

The absorption process happens after the food has been reduced to chemicals and it starts to absorb needed chemicals. The absorption process begins inside the stomach in which molecules are absorbed like, water and alcohol, that goes straight into the bloodstream. The absorption process does much of the work  inside of the small  intestine when the folds of the intestinal walls maximize contact with the digested food. Small blood and lymphatic vessels will take the molecules and carry it to the rest of the body. The large intestine will then absorb the rest of the water and vitamins B and K before it becomes feces and leaves the body.

The last step is Excretion

Excretion is the final function in which the digestive system removes waste form the body through defecation. Defecation process will remove indigestible  substance  that do not stay inside the gut. The defecation process is voluntarily controlled by the brain, and must happen on a regular bases to prevent backup of indigestible materials.