1. The Human Digestive System
Unit 2

2. The Basic Functions of the Digestive System
Ingestion-taking nutrients into the body, i.e., eating
Digestion-the mechanical and chemical breakdown of food into a usable form
Absorption-the movement of molecules through the mucosal lining of the stomach and small intestine, and into the blood
Excretion-the removal of solid waste from the body
Sphincters-circular muscles that contract and move food through the GI tract.

3. Quick Write/Pair Share
What is the difference between Ingestions, Digestion, and Absorption?
Share this with a neighbor, are your answers the same?

4. The Digestive Organs Mouth Pharynx Larynx Esophagus Stomach
Small Intestines – 3
duodenum, jejunum, ileum
Large Intestines – 4
ascending, transverse, descending, sigmoid
Rectum
Anus

5. Quick Write/Pair Share
From this list of organs, which ones sound like they should belong to another body system? Which ones and which systems would you pair them with?
Share this with a neighbor, are your answers the same?

7. Mouth Digestion starts here!!!
Mechanical Digestion- The breaking down physically of food by chewing (mastication). First stage of digestion.
Chemical Digestion-Breaking down and converting of food chemically by enzymes into a suitable substance for absorption. In the mouth, Chemical Digestion of Carbohydrates begin.

8. Pharynx Also called the throat Nasopharynx
Oropharynx
Laryngopharynx
A passageway for food, liquids, and air

9. Esophagus Muscular tube located behind the trachea
(About 10 inches long)
Transports food from the pharynx to the stomach
Has both Upper and Lower esophageal sphincters

10. Stomach J-shaped pouch located below the diaphragm
Chemical digestion of protein occurs in the stomach due to gastric juice secretion
Mechanical digestion occurs in the stomach due to maceration (churning). Three layers of muscles in the stomach create the movement of maceration.

11. Quick Write/Pair Share
What is the difference between mastication and maceration? Where does each occur?
Share this with a neighbor, are your answers the same?

13. Small Intestines
Chemical digestion of nutrients and absorption of nutrients is completed in the small intestines
Three divisions of the small intestines:
Duodenum – first portion of the small intestine where the majority of chemical digestion occurs.
Jejunum – middle portion of the small intestine where the majority of absorption of nutrients occurs.
Ileum – final portion of the small intestine where absorption occurs.

15. Large Intestines
The large intestines are the last part of the digestive system.
Absorption of water, vitamins, electrolytes, production of vitamin K, and formation of feces occurs in the large intestines.
Consists of the Ascending, Transverse, Descending, and Sigmoid colons.

17. Rectum
The last portion of the large intestine which functions as a temporary storage of solid wastes before excretion.

18. Anus
The final portion of the rectum where solid waste is excreted from the body.