The Digestive SystemBy: Jennifer and Lizzie

What is the Digestive System?Digestion is the chemical and mechanical breakdown of food into smaller components called nutrients so they can be used by the body. Digestion starts in the mouth with mechanical digestion called mastication and chemical digestion by saliva. Most mechanical digestion is in the mouth. At the end of digestion waste material is eliminated during defecation. We will now show you what it takes to digest your food every time you eat.

Mouth● The teeth chew up the food so that it can go down

the pharynx and esophagus. Saliva helps break down the food - specifically startches - and moistens the food so it moves easier.

● The chemical processes in the stomach work better when the food is chewed.

Pharynx● The pharynx is part of the digestive system and

respiratory system. ● The pharynx is part of the throat, situated below

the mouth and nasal cavity.● The pharynx is also an important part of

vocalization.

Esophagus ● The esophagus is a long tube which pushes food

to the stomach. No digestion occurs in the esophagus.

● The esophagus is between the pharynx and stomach.

Stomach● The stomach is an organ of digestion that

receives food from the esophagus. ● The stomach churns the food and secretes

hydrochloric acid and enzymes that help digest food.

Small Intestine● The small intestine is the main place your

body absorbs the nutrients from food. The nutrients are now small enough to pass through the walls of the small intestine and into the blood. Blood cells then carry the nutrients throughout your body.

Pancreas● The pancreas releases pancreatic juices and

alkaline solution which neutralizes the chyme and breaks down fats, protein and carbohydrates.

● Chyme is the pulpy, acidic fluid - consisting of gastric juices and partly digested food - that passes from the stomach to the small intestine.

Liver● The liver produces enzymes necessary for

digestion and releases them as bile. ● It also decomposes red blood cells.● The liver has a thin double-layered

membrane that reduces friction between other organs.

Gall-bladder● Essentially the gallbladder is not required to live. ● It is responsible for storing bile which digests fats

in food. ● Many people, when eating an unusually high fat

meal, will have pain called a gall bladder spasm.

Large Intestine● The large intestine contains the appendix,

colon, and rectum.● Its function is to absorb water and minerals

from the remaining indigestible food. ● The large intestine passes useless waste

material.

Rectum● The rectum is the final part of the digestive

tract and is where faeces, the waste products of digestion, are stored until they are expelled from the body. All the waste will then leave by the anus.

Anus● The anus is the opening at the lower end of

the alimentary canal where solid waste is eliminated from the body.

● The anus is a circular muscle (sphincter) which expands to send unwanted indigestible waste out of the human body.

Quiz● What does the esophagus do in the

digestive system?● What is it called when you have a pain in

your gall bladder?● What does saliva do?● Where in your body is the pharynx?