digestive system
DESCRIPTION
Digestive System. Getting Ready Activity. Materials: (per pair) 1 piece of paper 1 pen Instructions: Going back and forth between you and your partner, try to map the journey that food takes as it goes through the digestive system - PowerPoint PPT PresentationTRANSCRIPT
Digestive System
Getting Ready Activity
Materials: (per pair)1 piece of paper1 pen
Instructions:• Going back and forth between you and your
partner, try to map the journey that food takes as it goes through the digestive system
• Be as detailed as possible (try to mention at least 8 organs)
• You have one minute to complete the activity
Language Connection• The digestive tract is often called the ‘gastrointestinal’ tract,
or GI tract for short• Gastro (greek) = stomach• Intestinal = intestines
Gastric – of or relating to the stomachGastronomy – study of the culture of foodGastric bypass – surgery that bypasses the stomachGastroenteritis – inflammation (infection) of the stomach
Digestive System• The organ system that is made up of the mouth,
esophagus, stomach, intestines, liver, pancreas, and gall bladder
• The system that takes in (ingestion), breaks up (digestion), absorbs (absorption), and eliminates wastes (egestion)
The GI Tract
• Essentially one long tube with two openings (mouth and anus) with accessory organs
• Gastrointestinal tract:Mouth Esophagus Stomach Small Intestine
Large Intestine Rectum Anus
• Accessory organs:Salivary glandsLivergall bladderpancreas
Tissues of the Digestive System• The entire digestive tract is lined with epithelial tissue• Goblet cells secrete mucus• Mucus protects the tract from digestive enzymes, and
lubricates the passage for the food• The tract also contains
muscle which allows the food to be pushed alongthe tract (peristalsis)
Warning... Gross video ahead
Mouth• Starting point of digestion• Mechanical digestion:
Mouth and Tongue – break apartFood
• Chemical digestion:Saliva – Saliva contains enzymes that break
down food. Saliva also lubricates the food.• Once broken up, the food (now a bolus) is swallowed
Esophagus• Long tube surrounded by muscle• The muscle contracts and relaxes
to push food along toward the stomach (peristalsis)
Stomach• Muscular organ that holds and churns food to continue
the process of digestion• Strong acids (Hydrochloric acid HCl) and enzymes are
secreted in the stomach to digest food• Acid that splashes up into the esophagus is the cause of
heartburn
Small Intestines• Small intestine is actually quite long – approximately 6m• Partially digested food that leaves the stomach is further
digested• Nutrients are absorbed
Large Intestines (Colon)• Large intestine are about 1.5m in length, but larger in
diameter than S. Intestine• Water is reabsorbed• Trillions of bacteria live in
your colon• They provide you with
vitamins (K, and biotin)
Warning – Frog picture ahead