The Digestive System
~Notes~
What is the digestive system?:
The body uses the nutrients that are broken down from food through the digestive system for cell
development, repair, and energy production. The process transforms food into absorbable substances
by combining mechanical and chemical digestion with the cooperation of several organs.
Main Components and Their Functions:
1. Mouth:
➔ Teeth: Use mechanical digestion to chew food and break it into tiny bits.
➔ Salivary Glands: Secrete saliva that starts the chemical digestion process by breaking
down carbs with the help of enzymes like amylase.
➔ Tongue: Aids in swallowing and in combining food with saliva.
2. Pharynx and Esophagus:
➔ Pharynx: Food and air passageway; starts the swallowing process.
➔ Esophagus: A muscular tube that uses peristalsis, or wave-like muscle contractions, to
move food from the pharynx to the stomach.
3. Stomach:
➔ Gastric juices: Include pepsin and hydrochloric acid, two enzymes that break down
proteins.
➔ Mechanical Digestion: Food and stomach juices are mixed by churning action to create
chyme.
➔ Mucus Lining: The mucous lining of the stomach shields the walls from acidic
substances.
4. Small Intestine:
➔ Duodenum, Jejunum, Ileum: The three areas of the body where most digestion and
absorption take place
➔ Enzymes and Bile: Found in the liver and gallbladder facilitate the breakdown of lipids,
proteins, and carbs.
➔ Villi and Microvilli: Increase surface area for nutrient absorption into the
bloodstream.
5. Pancreas:
● generates bicarbonate and digestive enzymes such as lipase, proteases, and amylase to
counteract stomach acid.
~Notes~
What is the digestive system?:
The body uses the nutrients that are broken down from food through the digestive system for cell
development, repair, and energy production. The process transforms food into absorbable substances
by combining mechanical and chemical digestion with the cooperation of several organs.
Main Components and Their Functions:
1. Mouth:
➔ Teeth: Use mechanical digestion to chew food and break it into tiny bits.
➔ Salivary Glands: Secrete saliva that starts the chemical digestion process by breaking
down carbs with the help of enzymes like amylase.
➔ Tongue: Aids in swallowing and in combining food with saliva.
2. Pharynx and Esophagus:
➔ Pharynx: Food and air passageway; starts the swallowing process.
➔ Esophagus: A muscular tube that uses peristalsis, or wave-like muscle contractions, to
move food from the pharynx to the stomach.
3. Stomach:
➔ Gastric juices: Include pepsin and hydrochloric acid, two enzymes that break down
proteins.
➔ Mechanical Digestion: Food and stomach juices are mixed by churning action to create
chyme.
➔ Mucus Lining: The mucous lining of the stomach shields the walls from acidic
substances.
4. Small Intestine:
➔ Duodenum, Jejunum, Ileum: The three areas of the body where most digestion and
absorption take place
➔ Enzymes and Bile: Found in the liver and gallbladder facilitate the breakdown of lipids,
proteins, and carbs.
➔ Villi and Microvilli: Increase surface area for nutrient absorption into the
bloodstream.
5. Pancreas:
● generates bicarbonate and digestive enzymes such as lipase, proteases, and amylase to
counteract stomach acid.
