Science: The Digestive System
How food moves through and is broken down by the body
Science: The Digestive System
How food moves through and is broken down by the body
Biology - Grade 6-8
- 1
What is the main job of the digestive system?
Think about what your body needs to get from food after you eat it.
The main job of the digestive system is to break food into smaller nutrients that the body can absorb and use for energy, growth, and repair. - 2
List the organs food passes through in order from the mouth to the end of the digestive tract.
Food passes through the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus in that order. - 3
Explain what happens to food in the mouth.
Include both chewing and saliva in your answer.
In the mouth, teeth mechanically break food into smaller pieces, and saliva begins chemical digestion by helping break down some starches. The tongue also helps move food so it can be swallowed. - 4
What is the role of the esophagus in digestion?
The esophagus moves swallowed food from the mouth to the stomach by rhythmic muscle contractions called peristalsis. - 5
Describe two important things the stomach does during digestion.
Think about both movement and chemicals.
The stomach stores food for a short time and churns it to mix it with digestive juices. It also uses acids and enzymes to help break food down further, especially proteins. - 6
Why is the small intestine an important part of the digestive system?
The small intestine is important because most chemical digestion is completed there, and most nutrients from food are absorbed into the bloodstream there. - 7
What is the job of the large intestine?
Focus on what happens to water.
The large intestine absorbs water and some salts from the remaining material after digestion. It also helps form solid waste before it leaves the body. - 8
How do villi help the small intestine do its job?
Villi are tiny fingerlike structures that increase the surface area of the small intestine. This larger surface area helps the body absorb more nutrients efficiently. - 9
Name one organ that helps digestion but food does not pass through, and explain how it helps.
The liver and pancreas are both good examples.
One example is the liver, which makes bile to help break down fats. Another example is the pancreas, which releases digestive enzymes that help break down food in the small intestine. - 10
What is peristalsis, and why is it important?
Peristalsis is a series of wave-like muscle contractions that pushes food through the digestive tract. It is important because it keeps food moving from one organ to the next. - 11
A student says digestion only happens in the stomach. Is this correct? Explain your answer.
Think about where digestion starts and where most absorption happens.
This is not correct. Digestion begins in the mouth, continues in the stomach, and is completed mostly in the small intestine, where many nutrients are also absorbed. - 12
After nutrients are absorbed from the small intestine, what happens next in the body?
After nutrients are absorbed, they enter the bloodstream and are carried to body cells. The cells use these nutrients for energy, growth, repair, and other life processes.