In this Grade 7 Life Science lesson from Chapter 18, students learn how the digestive system breaks down food through both mechanical and chemical digestion, and how nutrients such as proteins, carbohydrates, fats, and water are processed into usable forms for the body. Students explore key vocabulary including digestion, peristalsis, and nutrients, and examine how wavelike muscle contractions move food through the digestive system. Hands-on investigations model how substances like saliva chemically break down starch and how fats are emulsified during digestion.
Section 1
Digestive System Transforms Food Into Usable Materials
Digestion breaks down food physically through grinding and chewing, and chemically through enzymes and acids. This process converts nutrients like proteins, carbohydrates, and fats into forms your body can use.
Section 2
Nutrients Provide Energy and Building Blocks
Your body requires proteins for growth and repair, carbohydrates for energy, fats for energy storage, and water for all cellular functions. These nutrients enable your body to move, grow and maintain homeostasis.
Section 3
Food Travels Through Specialized Organs
Food journeys from the mouth through the esophagus, stomach, small intestine, and large intestine. Along the way, mechanical forces break it down while chemicals transform it into absorbable nutrients.
Section 4
Accessory Organs Release Crucial Chemicals
The liver produces bile to break down fats, the gallbladder stores this bile, and the pancreas creates enzymes that digest proteins, fats, and starches. Without these chemicals, your body couldn't use food for energy.
Section 5
Villi Absorb Nutrients Into Bloodstream
Specialized structures called villi line the small intestine, creating a large surface area that absorbs digested nutrients. Once absorbed, these nutrients enter your bloodstream for distribution throughout your body.
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Section 1
Digestive System Transforms Food Into Usable Materials
Digestion breaks down food physically through grinding and chewing, and chemically through enzymes and acids. This process converts nutrients like proteins, carbohydrates, and fats into forms your body can use.
Section 2
Nutrients Provide Energy and Building Blocks
Your body requires proteins for growth and repair, carbohydrates for energy, fats for energy storage, and water for all cellular functions. These nutrients enable your body to move, grow and maintain homeostasis.
Section 3
Food Travels Through Specialized Organs
Food journeys from the mouth through the esophagus, stomach, small intestine, and large intestine. Along the way, mechanical forces break it down while chemicals transform it into absorbable nutrients.
Section 4
Accessory Organs Release Crucial Chemicals
The liver produces bile to break down fats, the gallbladder stores this bile, and the pancreas creates enzymes that digest proteins, fats, and starches. Without these chemicals, your body couldn't use food for energy.
Section 5
Villi Absorb Nutrients Into Bloodstream
Specialized structures called villi line the small intestine, creating a large surface area that absorbs digested nutrients. Once absorbed, these nutrients enter your bloodstream for distribution throughout your body.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter