Transcript SBI3U - 10.2

Section 10.2: The Human
Digestive Tract
Page 338-342
Mouth
• Mechanical digestion: teeth
• Chemical digestion: salivary glands release saliva
• Mucin = lubricant to facilitate the movement of food
Esophagus
• Lined with muscles to push food along
Epiglottis
• Prevents food from entering your trachea
Pharynx
• Located behind mouth and connects the esophagus and
trachea
Stomach
• Lined with gastric glands
• Muscles break food down mechanically
• Pyloric sphincter  valve controls the flow of food
out of the stomach
The Small Intestine
• duodenum = further chemical breakdown and
contain fingerlike-projections called villi
• jejunum = further break down
• ileum = absorbs nutrients, pushes undigested
material into large intestine
Relaxes and
contracts
The Small Intestine
The Large Intestine
• 3 parts:
Ascending colon
Transverse colon
Descending colon
• Removes water
from waste
material
Peristalses
• Muscles contract and relax to push food down
Chemical Digestion
Hydrolysis = break apart with water
3 Types of enzymes
1.Carbohydrases = breaks down carbohydrates
(sugars)
2.Lipases = breaks down lipids (fats)
3.Proteinases = breaks down proteins
Chemical Digestion
Mouth
• Enzyme amylase breaks down starch into sugars
Stomach
• Enzyme pepsin breaks down proteins
Organs Involved in Digestion
The Liver
• Create bile salts  breaks
down fat globules
• Detoxification
The Pancreas
• Source of digestive enzymes
The Gall Bladder
• Stores bile to digest fats
http://videos.howstuffworks.com/hsw/18425-inside-storybreaking-down-digestion-video.htm
http://kidshealth.org/kid/htbw/digestive_system.html