THE DIGESTIVE SYSTEM

Functions Ingestion

Enters the mouth (ingested) Digestion

As soon as food enters mouth digestion begins Breaks down food (mechanical and chemical

process) Absorption

Nutrients are absorbed in bloodstream Elimination

Unused substances are eliminated

Mechanical? Chemical? BOTH!

Mechanical digestion takes place when food is chewed, mixed and churned

Chemical digestion occurs when chemical reactions break down food.

Alimentary Canal (Digestive tract)

MouthEsophagusStomachSmall intestineLarge intestineRectumAnus

Food passes through these organs!

How does food move through? Peristalsis!

Waves of muscle contractions!

Accessory organs Food does not pass through these

organs! They aid in the breakdown of food. (Helpers!) Tongue Teeth Salivary glands Liver Gallbladder Pancreas

What happens at each stage?Identify if mechanical and/or

chemical digestion is taking place……

What is the main job of the organ?

Mouth (Digestion begins!)

Mechanical digestion happens when you chew your food with your teeth and mix it with your tongue

Chemical digestion begins when the saliva mixes in and helps to break down the food

Thank you epiglottis! This flap saves us from choking by protecting the windpipe to prevent food from entering it.

That way…the food goes right from the mouth to the…..

Esophagus

A muscular tubeNO digestion takes place here!Smooth muscles move the food

downwardwith the help of peristalsis!!!Secretions from the mucus glands help

keep food moist!

Stomach Muscular bag Mechanical and chemical digestion take

place here! Mechanically food is mixed in the stomach by

peristalsis Chemically food is mixed with enzymes and

hydrochloric acid Mucus is released to protect the stomach Food is now called CHYME.

Small Intestine Food enters the duodenum…the first part

of your small intestine. MOST digestion takes place here!

Chemical digestion—bile added from gall bladder and liver to break down fats, a solution from the pancreas is mixed in to neutralize the stomach acid and break down sugar.

Absorption of broken down food (chyme) takes place here. Nutrients move into the blood stream to be delivered to all cells of your body.

Peristalsis continues to force the remaining undigested and unabsorbed materials into the next stage…..

Large Intestine When food enters, it is still a watery

mixture. Water is absorbed here from the

undigested material. This helps to maintain homeostasis!!

Peristalsis is slowing down and the material moves into…..

Rectum and Anus

Muscles in the rectum and anus control the release of waste from the body…….