How The Digestive System Works
Digestion works by moving food through the gastrointestinal (GI) tract. Digestion begins in the mouth with chewing and ends in the small intestine. As food passes through the GI tract, it mixes with digestive juices, causing large molecules of food to break down into smaller molecules.
Mechanical Digestion: Physical breakdown of food
Chemical Digestion: Involves the action of enzymes
Teeth: Shreds and grinds the food into smaller pieces
Structure: Enamel, dentin, and pulp
Function: To shred and grind food into smaller pieces
Location: Mouth
Structure: Enamel, dentin, and pulp
Function: To shred and grind food into smaller pieces
Location: Mouth
Saliva: As you chew your food, the salivary glands release saliva that moistens the food
Function: softens food, lubricates the throat and mouth and begins digestion
Location: Mouth, Salivary glands
Enzyme Involved: Amylase
Function: softens food, lubricates the throat and mouth and begins digestion
Location: Mouth, Salivary glands
Enzyme Involved: Amylase
Tongue: Once food has been chewed and mixed with saliva, the tongue pushes it to the back of the mouth
Function: the tongue rolls the food into balls and pushes them to the back of the mouth
Location: Mouth
Function: the tongue rolls the food into balls and pushes them to the back of the mouth
Location: Mouth
Esophagus: A muscular tube that connects the mouth to the stomach
Structure: Usually between 25 to 30 centimeters long
Function: Transports saliva, liquids and foods from the mouth to the stomach
Location: Behind the trachea and the heart and in front of the spin
Structure: Usually between 25 to 30 centimeters long
Function: Transports saliva, liquids and foods from the mouth to the stomach
Location: Behind the trachea and the heart and in front of the spin
Stomach: Muscular sac that can stretch to nearly twice its original size and holds up to 2 liters (2 qt) of food
Function: Breaks down starches into simple sugars
Location: Left side of the upper abdomen
Enzyme Involved: Pepsin
Food Broken Down: Protein
Function: Breaks down starches into simple sugars
Location: Left side of the upper abdomen
Enzyme Involved: Pepsin
Food Broken Down: Protein
Pancreas: It makes digestive enzymes as well as hormones that regulate how much glucose the body stores and use
Location: back of the abdomen, behind the stomach
Enzymes Involved: Proteases, Lipase, Trypsin, and Amylase
Food Broken Down: Starches, proteins, and fats
Location: back of the abdomen, behind the stomach
Enzymes Involved: Proteases, Lipase, Trypsin, and Amylase
Food Broken Down: Starches, proteins, and fats
Liver: Filters blood, is also a digestive organ. It produces a chemical substance, bile, that helps digest fats
Location: Under the diaphragm in the upper-right hand side of the abdomen
Food Broken Down: Fats
Location: Under the diaphragm in the upper-right hand side of the abdomen
Food Broken Down: Fats
Gallbladder: Small sac-shaped organ beneath the liver, in which bile is stored after secretion by the liver and before release into the intestine
Structure: small pear-shaped sac, about three or four inches long by one inch wide
Function: primary function is to store and concentrate bile, a yellow-brown digestive liquid produced by the liver
Location: Beneath the liver
Enzyme Involved: Lipase
Structure: small pear-shaped sac, about three or four inches long by one inch wide
Function: primary function is to store and concentrate bile, a yellow-brown digestive liquid produced by the liver
Location: Beneath the liver
Enzyme Involved: Lipase
Small Intestine: Long, narrow tube in which most digestion takes place
Structure: 6 meters in length
Function: Churns the food, and chemical digestion and breaks down the complex molecules
Location: Coiled in the center of the abdominal cavity
Enzymes Involved: Lipase, Amylase
Food Broken Down: Starches, proteins, fats, and carbohydrates
Structure: 6 meters in length
Function: Churns the food, and chemical digestion and breaks down the complex molecules
Location: Coiled in the center of the abdominal cavity
Enzymes Involved: Lipase, Amylase
Food Broken Down: Starches, proteins, fats, and carbohydrates
Duodenum: The first part of the small intestine immediately beyond the stomach, leading to the jejunum
Structure: 25-38 cm, C-shaped structure
Function: to receive the partly digested foods from the stomach and finish the digestion process
Location: between the stomach and the middle part of the small intestine, or jejunum
Enzymes Involved: Lipase, Amylase, and Trypsin
Structure: 25-38 cm, C-shaped structure
Function: to receive the partly digested foods from the stomach and finish the digestion process
Location: between the stomach and the middle part of the small intestine, or jejunum
Enzymes Involved: Lipase, Amylase, and Trypsin
Villi: Small finger-like projections covered with epithelial cells, that absorb nutrients
Structure: Tiny ridge formations on the inner wall of the small intestine
Function: Absorb carbohydrates, lipids, nucleic acids, and proteins into the circulatory and lymphatic system
Location: Located in all three parts of the small intestine, the ilium, jejunum, and duodenum
Enzymes Involved: Trypsin and Lipase
Structure: Tiny ridge formations on the inner wall of the small intestine
Function: Absorb carbohydrates, lipids, nucleic acids, and proteins into the circulatory and lymphatic system
Location: Located in all three parts of the small intestine, the ilium, jejunum, and duodenum
Enzymes Involved: Trypsin and Lipase
Microvilli: Each of a large number of minute projections from the surface of some cells
Structure: Tiny extensions of the plasma membrane
Function: Increase surface area of a cell
Location: Small intestine
Structure: Tiny extensions of the plasma membrane
Function: Increase surface area of a cell
Location: Small intestine
Large Intestine: The large intestine absorbs about 1 liter of water a day, along with some salts
Structure: 1.5 meters (5 ft) long about twice the diameter of the small intestine
Function: Helps maintain the body's fluid balance
Location: Gastrointestinal
Enzyme Involved: Lipase
Structure: 1.5 meters (5 ft) long about twice the diameter of the small intestine
Function: Helps maintain the body's fluid balance
Location: Gastrointestinal
Enzyme Involved: Lipase
Rectum: A tube that connects the lard intestine to the anus
Structure: Tube
Function: Stores the feces
Location: The large intestine
Enzyme Involved: miofilament
Structure: Tube
Function: Stores the feces
Location: The large intestine
Enzyme Involved: miofilament
Peptic Ulcers: A lesion in the lining of the digestive track
Location: Typically in the stomach or duodenum
Location: Typically in the stomach or duodenum
Heart Burn: A form indigestion felt as a burning sensation in the chest, caused by acid reg
Location: The heart
Location: The heart