The Digestive System - mrenns.com€¦The Digestive System The digestive system has 3 main...
Transcript of The Digestive System - mrenns.com€¦The Digestive System The digestive system has 3 main...
The Digestive System The digestive system has 3 main functions.
To breakdown food into smaller nutrients.
To absorb nutrients into the bloodstream.
To eliminate wastes from the body.
From Small to Big
The food we eat is not useful immediately.
But, these are too big for our body to use.
The 3 main nutrients in food are carbohydrates, proteins and fats.
G G G G G G
They must be broken into smaller pieces.
G G G G G G G G G
sugars
amino acids
fatty acids
carbohydrates
proteins
fats
Huge, useless molecules
Small, useful molecules
G G G G G G G G G
sugars
amino acids
fatty acids
carbohydrates
proteins
fats
Huge, useless molecules
Small, useful molecules
digestion
Digestion
Digestion is the break down of food into smaller nutrients.
There are 2 kinds of digestion:
Digestion
Digestion is the break down of food into smaller nutrients.
Physically breaking food down by
cutting, tearing and slicing.
Breaking down food by using chemicals
like acid and enzymes.
e.g. teeth
Mechanical
e.g. stomach
Chemical
Digestive System Organs
mouth
esophagus
stomach liver
gall bladder
salivary glands
pancreas
small intestine
large intestine
rectum
epiglottis
1. Mouth
Digestion starts in the mouth.
Both mechanical and chemical digestion begin in the mouth.
Your teeth tear & mash food into smaller pieces.
Saliva moistens and digests food using enzymes.
Mechanical Chemical
1. Mouth
Saliva is produced by the salivary glands.
There are 3 salivary glands surrounding
the mouth.
Saliva contains enzymes that break down carbohydrates
into sugars.
Epiglottis
When you swallow, the epiglottis directs the food down the esophagus.
The epiglottis is a small flap that blocks food from
entering the trachea.
epiglottis
esophagus trachea
Choking is caused by food entering
the trachea.
2. Esophagus
Food then moves down the esophagus.
The esophagus is a muscular tube that connecting the mouth to the stomach.
Circular muscles in the esophagus push
the food downward.
3. Stomach
Digestion continues in the stomach.
Both mechanical and chemical digestion continue in the mouth.
The stomach squeezes and
churns the food.
Acid & enzymes turn food into liquid form.
Mechanical Chemical
4. Small Intestine
Food enters the small intestine in liquid form.
The small intestine finishes chemical
digestion and then absorbs nutrients
into the blood.
Other organs produce enzymes to help with chemical digestion…
Enzymes made in 3 organs help with digestion:
Makes enzymes to
digest starch and fats.
Makes an enzyme
called bile to digest fats.
Makes enzymes to
digest starch, proteins and
fats.
liver s. intestine
4. Small Intestine
pancreas
Absorption
3-5 hours after eating, food in the small
intestine is fully digested.
The small nutrients can now be absorbed into
the bloodstream.
The nutrients cross through the walls of
the intestine. blood s. intestine
The intestine is designed to help absorption.
Absorption
The small intestine has millions of tiny folds called villi that make the surface
area of the intestine much greater.
4. Large Intestine
Material entering the large intestine is mainly water and undigested food.
The lg. intestine has 2 jobs:
2. Package undigested food into waste
1. Absorb needed water from the food
5. Rectum
The rectum is a short tube below the intestine.
The rectum compacts the waste into solid
form - your poo!
When there is enough, the waste is passed from
the body through an opening called the anus.
The End