Science Starter What is the order that food passes through the digestive organs? What is the role of the small intestine in the body? In Earth Science, what is the difference between chemical and mechanical weathering?

Today’s Agenda Science Starter Digestion Notes Enzymes & Digestion Article Accessory Organs Exit Quiz

The Digestive System Unit 7

15.1: Overview Functions: mechanical and chemical breakdown of food        *absorption of nutrients Consists of alimentary canal and accessory organs

Wall of the Alimentary Canal

Mixing Movements Contractions mix food with digestive juices   Peristalsis - pushes food down the tube

15.2 Digestive System Organs esophagus 2.  liver 3.  stomach 4. pyloric sphincter 5.  duodenum 6.  pancreas 7.  jejunum 8.  ileum 9.  cecum 10. appendix 11.  ascending colon 12.  descending colon 14.  anus

Esophagus Esophageal hiatus is where it penetrates the diaphragm   Lower Esophageal sphincter at entrance to stomach

Stomach

Stomach Gastric Juices contain acids that break down food  - secreted by gastric glands PEPSIN  - most important digestive enzyme for breaking down food   Mucus prevents stomach from digesting itself  

Chyme - paste, after food has been broken down, released then into the duodenum via the pyloric sphincter valve

PANCREAS Secretes insulin which breaks down sugars Pancreatic Juice also breaks down fat

 Liver  1 large right lobe  | 1 smaller left lobe

Liver Functions 1. Blood glucose levels 2.  Breakdown of lipids and fats 3.  Protein metabolism 4.  Stores vitamins 5.  Destroys damaged RBCs 6.  Removes toxins 7.  Secretes bile

Gall Bladder - under liver cystic duct --> common bile duct, stores bile, digests fat                  *gallstones may form  

Small Intestine 1. Duodenum 2. Jejunum 3. Ileum   Starts at the pyloric sphincter 1.  Duodenum 2.  Jejunum 3.  Ileum

Intestinal villi - increase surface area to absorb nutrients, connect to vessels

Small Intestine = ABSORPTION

Large Intestine   Cecum  Appendix Colon (4 parts) Rectum Anus

Function of Large Intestine The main job is    WATER REABSORPTION...

*Read the article on digestion* 15.3 Types of Digestion Mechanical- physically breaking the food into smaller pieces. Begins in the mouth (chewing) Chemical- breaking down the food into simpler nutrients that can be used by the cells. Begins in the mouth when food mixes with saliva *Read the article on digestion*

Accessory Organs & Organ System Color the accessory organs and read about the pancreas, liver, and gallbladder When you finish pick up a digestive system organ cut out. Put the organs together, color them, and place them on a sheet of large paper sheet!

**Homework: Food Particle Story** Exit Quiz Where does mechanical digestion occur? Where does chemical digestion occur? What is the role of the pancreas in digestion? List all of the accessory organs **Homework: Food Particle Story**