1. THE DIGESTIVE SYSTEM

2. ON YOUR DIAGRAM
a) label the parts of the digestive system ​that you know, then use your textbook (Chp. 35) to help you out. b)We will review the labelling c) Use your textbook to complete the ​Function of the parts you have identified on the hand-out provided

4. THE DIGESTIVE SYSTEM Composed of two main portions:
The Alimentary Canal
Through which materials for digestion move
Accessory Organs
From which secretions, enzymes and juices aid the digestive process

5. 4 MAIN PARTS OF THE DIGESTIVE SYSTEM
1) Ingestion: the taking IN of nutrients 2) Digestion: the breakdown of organic molecules into ​smaller compounds a) Mechanical Digestion -the physical breakdown of food (chewing, ​grinding, peristalsis [stomach action or ​churning]) b) Chemical Digestion -the breakdown of the complex molecules ​into simple ones by the action of enzymes

6. 4 MAIN PARTS OF THE DIGESTIVE SYSTEM
3) Absorption: the transport of digested nutrients to the ​tissues of the body 4) Egestion: the removal of materials from the body that cannot be digested Trip Through the Digestive System

7. STRUCTURE & FUNCTIONS Tongue Function: To taste food
Shapes food into a ball called a bolus
Push food to the back of the mouth into the pharynx
Teeth
Function: to cut, tear, smash and grind food into small pieces and form a paste

8. STRUCTURE & FUNCTIONS Salivary Glands
Function: to produce saliva in response to smell, feel, taste or thought of food Saliva contains SALIVARY AMYLASE, which begins to break down starches
Epiglottis
Function: a flap of tissue that covers the wind pipe (trachea) when swallowing

9. STRUCTURE & FUNCTIONS Esophagus
Function: A muscular tube that moves food from the pharynx to the stomach uses muscle action called peristalsis.
Note: Peristalsis is the wave like motion of muscular tissue that pushes substances through out digestive system!
Pharynx
Function: the part we call our throat, connection the mouth and esophagus

10. STRUCTURE & FUNCTIONS Sphincters
Function: a ring of muscle that separates the stomach from the small intestine. Opens and closes to control the movement of food into intestines
Acts like a purse strong that can open and close
3 Sphincters in Digestive System
1) Cardiac sphincter: prevents the regurgitation of the stomach contents back into the esophagus.
2) Pyloric sphincter: located at the end of the pyloric canal of the stomach, and controls gastric secretions.
3) Ileocecal sphincter: located at the end of the small intestine, and prevents the contents of the small intestine from entering the large intestine.

11. STRUCTURE & FUNCTIONS Stomach
Function: stores food and releases it slowly into small intestine
Helps break down food (mechanical digestion)
Produces gastric juices that help digest food
Product leaving the stomach is called Chyme
Small Intestine
Function: digests food into small molecules and to absorb the molecules into the bloodstream
Is about 20 feet long
Is the place where most absorption occurs
Villi line the small int. & function absorb nutrients

12. STRUCTURE & FUNCTIONS How the Small Intestine Works 1. Duodenum
The first part of the small intestine
The main role is to complete the 1st phase of digestion
Food from the stomach is mixed with enzymes from the pancreas and bile from the gallbladder. The enzymes and
the bile help to break down food into smaller molecules
2. Jejunum
The second part of the small intestine
The inside walls absorb the food nutrients
Have circular folds called villi, which increase SA to absorb nutrients
3. Ileum
The third part of the small intestine
Its absorbs bile acids, which are returned to the liver to be made into more bile, then stored in the gallbladder for future use
Also absorbs vitamin B, which the body uses to make nerve cells and red blood cells.

13. STRUCTURE & FUNCTIONS Large Intestine (Colon)
Function: to absorb remaining water from food waste
Semi-solid feces are formed
About 5 feet long
Some complex carbohydrates are digested here
Rectum
Function: Stores feces until they can be eliminated
Final 6 inches of large intestine
Can expand

14. STRUCTURE & FUNCTIONS Appendix
Function: extension of first part of large intestine
Leftovers of digestion flow through here
Helps in the body’s defense against disease, but we don’t need it to be healthy
Storage for good “gut” bacteria
Liver
Function: to produce bile (a chemical that helps to digest fats)
Regulates blood glucose levels
Converts toxic ammonia into urea and detoxifies harmful substances we ingest
Stores fats and carbohydrates for energy
Gall Bladder
Function: to store and concentrate the bile produced in the liver
Releases bile and bile salts into small intestine through the bile duct
Note: If proteins & fats are detected in the intestine, the GB is stimulates to release stored bile

15. STRUCTURE & FUNCTIONS Pancreas
Function: to produce digestive juices that help to reduce the acidity of gastric juice from stomach
To produce:
Insulin (hormone) which controls sugar levels in the blood
Amylase – breaks down starch
Trypsin – Breaks down proteins
Lipase – breaks down fat
Sodium bicarbonate – helps neutralize stomach acid (basic)
Uvula
Function: to cover the breathing passage between your nose and mouth when you swallow
Helps change the sound of your voice