Transcript The Functions of the Digestive System

Why do we need food?
Gives us energy to function.
Provides body with materials to
grow and repair tissue.
Nutrients – Carbohydrates (CHO),
fats, proteins, vitamins,
minerals, and water.
The Functions of the
Digestive System
1. Breaks down food into smaller bits and
then into molecules.
2. Food molecules, glucose and proteins,
are absorbed into the blood.
3.Blood carries nutrients throughout the
body.
4. Undigested food, wastes, are
eliminated from the body
Digestion
Digestion –
Process of the
body breaking
down food
into small
nutrient
molecules.
Types of Digestion
1. Mechanical Digestion – the tearing, grinding and
mashing of food. Occurs in mouth and stomach
2. Chemical Digestion – chemicals are added to food
to help in the final break down so it can be
absorbed.
Enzyme – proteins that speed up chemical reactions.
Absorption
Absorption – the process where
nutrient molecules pass through the
walls of your digestive tract into
your blood stream.
Digestion Begins
1.THE MOUTH – mechanical and chemical digestion
- Teeth tear and grind food – mechanical
- Saliva mixes with food and contains an enzyme
that starts chemical digestion.
2. THE ESOPHAGUS
Esophagus – the muscular tube that leads from the
mouth to the stomach. Lined with mucus.
- Food only remains in the esophagus for about 10
seconds so very little digestion takes place
here.
The epiglottis is a flap of tissue that covers
the trachea when we eat.
Peristalsis – waves of muscle contractions in
the walls of the digestive tract that push
food through.
Food does NOT slide down any part of the
digestive tract.
Digestion Begins (cont.)
3. THE STOMACH
- Both Mechanical and Chemical digestion take
place in the stomach.
(Hyperlink to Stomach noises)
- Food is mashed and ground down into a liquid
(chyme) and mixed with hydrochloric acid
(HCl) and pepsin (an enzyme).
- Nutrients are NOT absorbed into the body
from the stomach.
- Gastric juices in our stomach help digest
food.
1. Pepsin – helps digest protein
2. Hydrochloric Acid (HCL) – Kills bacteria in
our stomach
Stomach is lined with MUCUS to protect it
from the acid.
Final Digestion
4. THE SMALL INTESTINE
- Longest part of digestive system
- Where MOST of chemical digestion takes
place.
- Where MOST of the nutrients are absorbed
into the bloodstream.
Absorption in the Small Intestine
Villi – millions of finger-like projections that
cover the inside of the small intestine.
Villi increase the surface area of the
intestines so we can absorb more nutrients
Final Digestion (cont.)
5. THE LIVER
- Produces Bile – a chemical that breaks up fat.
Stored in Gall Bladder
- Filters blood
- Where blood gets iron
6. THE PANCREAS
- Produces enzymes that break food down into
very small molecules
Final Digestion (cont.)
7. THE LARGE INTESTINE
- Contains bacteria that feed on undigested
food.
- Reabsorbs water from waste before the
waste is eliminated.
8. THE RECTUM
- Compresses waste into solid form.
9.
THE ANUS – opening at the end of the
rectum.