Digestive System Where does our food go?

Body Fuel Just like cars need gas to run, we need fuel for our bodies to function Rather than pouring gas into our bodies, we fuel up on food Your digestive system is what turns food into fuel for your body to function

Classified as mammals We are consumers – we eat plants or other animals for food We are not able to make food within our own bodies like producers

Food for energy We need energy for everything we do in the day Food provides us with the energy that keeps us going

Food for building Needed to build our bodies as we grow Needed to make new bone cells and new muscle cells Provides us with the material that helps our hair and nails grow, too The faster your grow and change, the more food you will need

Food for repairing Rebuild parts of our bodies Think about when you have scraped your knee. The food you eat can be used to make new skin cells, fix the broken blood vessels and replace the blood cells you lost.

Digestion process Break down of food into smaller parts that your body can use Two ways your food can change:  Mechanical digestion Physical changing of food  Chemical digestion Broken down into carbohydrates, proteins and fats

The Beginning: Your Mouth Mouth, or oral cavity, contains:  Teeth, tongue, and salivary glands Teeth  tear and grind up food  Mechanical digestion Tongue  allows you to enjoy the flavors  Help swallow

Organs that Help Digestion Salivary Glands  Make saliva, or watery liquid, that you may call spit  Help moisten food making it softer and easier to swallow  Beginning of chemical digestion  Contain enzymes that speed up chemical reactions. These enzymes are called salivary amylase

The Food Tube: The Esophagus Muscular tube About 10 in. (25 cm) long Stretches to allow food to pass through it Involuntary muscles contract and relax pushing your food toward your stomach The movement created by the contracting and relaxing muscles is called peristalsis

An Expandable Bag: The Stomach Attached to the end of the esophagus Looks like a bag shaped like a “j” When food enters your stomach it mixes with gastric juices.  Enzymes, acids and mucus Pepsin – enzymes that break down protein and fat Hydrochloric acid – breaks down protein Mucus – protects the stomach walls so they are not attacked by the strong acids and enzymes that are breaking down your food.

An Expandable Bag: The Stomach Food stays in your stomach 2 to 6 hours Mechanical digestion takes place as food and gastric juices are mixed Chemical digestion also takes place as the enzymes and acid break down the food you have eaten When the food and juices are fully mixed, the resulting mixture is called chyme

A Seven-Meter Tube: The Small Intestines When your food has been completely mixed and churned in your stomach, it moves to the small intestines 2.5 cm wide and over 21 feet long Long tube that is divided into three parts:  Duodenum  Jejunum  Ilium

A Seven-Meter Tube: The Small Intestines Duodenum  Digestive juices are added to chyme  The juices are made in the pancreas Break down carbohydrates, protein and fat  Bile, made by the liver and stored in the gall bladder, is responsible for breaking fats into smaller molecules

A Seven-Meter Tube: The Small Intestines Digestion is completed in the small intestines Food moves along through the long organ by the process of peristalsis

A Seven-Meter Tube: The Small Intestines Inside the small intestines are millions of villi  Tiny fingerlike projections surrounded by capillaries  The nutrients is absorbed by the villi and into the capillaries and put into the circulatory system.

A Two-Meter Tube: The Large Intestines Waste materials and fiber remain in your digestive system after nutrients have been removed 6 cm wide and m long Water is absorbed by the blood from the large intestines leaving a semisolid waste product. The waste product moves through the large intestines and is stored in the rectum The waste product is called feces. When the rectum becomes full, the fecal wastes are removed from the body through the anus.

Digestive System = mouth (teeth, tongue, saliva, enzymes)  esophagus  stomach (acids, enzymes, mucus, “chyme”)  small intestines (nutrients absorbed, pancreas, liver, gallbladder)  large intestines (water absorbed by blood)  rectum  anus