Foot entering the digestive system is broken down into simpler molecules in two ways, mechanic and chemical. Mechanic digestion involves muscles movement, i.e mouth (teeth) and peristaltic motion. Chemical digestion is conducted by digestive enzymes.
Digestive System in human
The process of digestion in human occurs outside the cell, and it is called extracellular digestion. Human digestive system includes digestive tract (mouth, pharynx, throat, stomach, small intestine, large intestine, anus) and digestive glands (liver pancreas).
Human put in the food they eat into the body by swallowing them, which is called ingestion. Mouth is completed with some devices, such as tongue, teeth, and salivary gland.
The function of tongue is to shift food around, push the food while swallowing, to taste, and as sensitive sense to temperature and pressure.
Baby teeth begin to come out after a child is six months old, which are known as milk teeth. The first set of milk teeth consists of 20 teeth, which are.
- Eight incisors (insisivus/I) to cut food;
- our canines (caninus/C) to shred food;
- Eight bicuspids to chew food.
The milk teeth begin to fall out when the child around 6-14 years old and they are replaced by a set of 32 permanent teeth. Permanent teeth consist of 8 incisor, 4 canines, 8 premolars (premolar/P), and 12 molar (molar/M).
Saliva is used to make food swallowing easier, digest food chemically because it contains amylase (ptialin) and lipase enzymes, and protect mouth membrane from hot or cold temperature and acid or alkaline condition.
The oral cavity of human is composed of three pairs of salivary glands, parotid gland (producing saliva), sublingual gland (producing water and mucose), and submaxillaris gland (producing water and mucose).
Pharymx, Throat, and Stomach
Pharynx and throat (oesophagus) are the connection tract between mouth and stomach.
Pharymx is a short portion here food tract and air tract meet. When the food is in the pharynx, soft muscled palate is elevated to prevent food from entering the nasal cavity; breathing will stop temporarily; larynx is elevated and epiglottis closes over to prevent food from entering the larynx. Tongue prevents the food from returning back into the mouth. Contraction of pharynx muscles propel the chewed food (bolus) into the oesophagus.
Oesophagus is a continuous, muscular, and thick walled tube. Bolus passes through the oesophagus toward stomach due to peristaltic movement of throat wall. Peristaltic movement is a wavy motion that travels backward causes by muscle contraction and relaxation alternately.