2 The digestive system is made of hollow organsjoined in a long, twistingtube from the mouth to theanus—and other organsthat help the body breakdown and absorb food.Functions:IngestionDigestionAbsorptionElimination
3 or to eat The first activity of the digestive system is to take in foodthrough the mouth.This process, calledingestion, has to takeplace before anythingelse can happen.
4 or to break down Digestion begins in the mouth with mechanical (physical digestion).Teeth helped by the tongue and lips(cut, tear, chop, grind and push)chew the food;at the same time salivary glandsproduce enzymes (chemicaldigestion) in saliva to helpbreak down food and swallow.The Human mouthcan make up to threepints of saliva a day.
5 The food is pushed to the pharynx (throat). Then into the esophagus (food tube); asmooth muscle that contracts automaticallyto push the food into the stomach.Digestion continues with churning andmixing actions in the stomach whichproduces a soup like mixture called chyme.The chyme then goes into the smallintesitne.The average human stomach holds about 48 ounces offood matter. Food stays in the stomach for two to threehours before it is emptied into the small intestine.
6 Absorption is when nutrients pass through the cell membrane in the small intestine into the blood orlymph capillaries.The liver produces a substance called bile,which is stored in the gall bladder and thensqueezed out into the intestine. Bile goes towork on the fat in foods, dissolving it into aliquid the body can digest.The average human small intestine is about 1.5to 2 inches wide. If you stretched it out, it wouldmeasure about 22 feet in length.
7 or to remove The food molecules that cannot be digested or absorbed move into the largeintestine where water is absorbed. Feces(brown solid waste) is then stored in therectum briefly.Elimination or defecation is the removalof indigestible wastes (feces) through theanus.
8 Large Intestine According to a study from the Stanford University School of Medicine, there aremore than 5,800 different species and strains ofbacteria in the human colon (large intestine).Most of them are benign or even beneficial. Someof them provide nutrients like vitamin K, andothers keep the bad bacteria under control.
9 A Foods Tale Digestion of food begins in the mouth, with mechanical breakdown of ingested materialby chewing with your teeth.Additionally, food in the mouth ismixed with saliva, whichcontains a digesting enzyme,known as amylase. This beginsthe chemical breakdown of foodbetter known as chemicaldigestion. After chewing, food isswallowed down the pharynx(throat), and enters theesophagus.
10 A Foods Tale The esophagus is a tube to transfer ingested material from the mouth tothe stomach – very little, if any,breakdown of food occurs in theesophagus.
11 A Foods Tale Food then passes into the stomach, where it is exposed to acid, and additionalenzymes promote proteinand fat breakdown.
12 A Foods Tale Next, food passes into the small intestine, where additional enzymes fromthe liver and pancreas aresecreted and mixed withfood, to further breakdown protein andcarbohydrates, and toemulsify fats. Additionally,food absorption occurs inthe small intestine. Ifbreakdown of ingestedmaterial and absorption donot occur normally symptomsof food intolerance result(diarrhea or constipation).
13 A Foods Tale Finally, food passes into the large intestine, where excesswater is absorbed, and water isstored in the form of feces.Food can stay in the largeintestine for a long time, up to96 hours! Very little in the wayof nutrients is absorbed by thecolon – if absorption hasn’toccurred in the small intestine,those leftover nutrients will bebroken down by the bacteria inthe colon.
14 A Foods Tale The solid parts of the food which have not been absorbed arestored in the rectum.When the rectum is full,the remains of the foodare passed out (eliminated)of the body through theanus.