Download Digestion

Digestive System
1 Function:
• Break down food into small molecules so it
can be absorbed and moved by the blood
which delivers it to your cells for energy.
Interactions with other systems
2 Types of digestion
2 types of digestion
• Mechanical: food is cut, mixed, or churned
into smaller pieces.
2 types of digestion
• Chemical: saliva, bile, and acid help break
down or dissolve the chemical bonds of
the food molecules
The Path of Food
1. Ingestion (eating)
2. Digestion (breaking down food
molecules)
3. Absorption (by cells)
4. Elimination (disposal of unused food)
Organs of the Digestive
System
1. Food is chewed in the mouth
•
•
Mechanical-chewing and ripping it into smaller
pieces
Chemical-saliva starts to dissolve starches
http://www.youtube.com/watch?v=CsYbO6zBR74
2. Slimy pieces of food slide down the
pharynx, past the epiglottis, into the
esophagus
http://www.youtube.com/watch?v=QvGYvK6qScE&feature=related
3. Food is squeezed down the esophagus
by muscle contractions called peristalsis.
4. Food lands in the stomach
• Mechanical digestion-food is churned and mixed
• Chemical digestion-food is mixed with enzymes
and acids to break it down.
http://www.youtube.com/watch?v=cp-SEs6dxR8&feature=related
heartburn video
5. 2-4 hours later, food is now a watery liquid
and it slowly moves into your small
intestine.
Stomach Stapling
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Small Intestine
6. In the small intestine food is digested even
more and then absorbed by the bloodstream.
7. Fat is chemically digested in the small
intestine by bile. The liver makes bile and
extra bile is stored in the gall bladder
• Carbohydrates, proteins, and fats are also
chemically digested by a digestive solution
made by the pancreas.
8. Millions of villi in the small intestine allow
the blood to pick up the nutrients (absorb)
to deliver to cells around the body.
http://www.youtube.com/watch?v=xu5jDCX2cHM
http://www.youtube.com/watch?v=_GTQBiZni6w
9. Remaining food and liquid is moved into
your large intestine by peristalsis.
10. Water is absorbed from the large
intestine back into the body.
http://www.youtube.com/watch?v=PpzfKt-47iA&feature=related
11. Remaining food is compacted and
released from the body as feces through
the rectum and anus.
The End!
1. Mouth
2. Salivary Glands
3. Gall Bladder
4. Liver
5. Pancreas
6. Small Intestine
7. Esophagus
8. Stomach
9. Large Intestine
10. Rectum
11. Anus
Review of digestion
1. Draw a plate of food
2. Food
goes into
the mouth
a. Mechanical digestion by teeth (tear dinner in
half)
b. Chemical digestion by saliva (tear dinner in
half again)
3. Food moves into the esophagus
No digestion
occurs
4. Into the stomach
a. Mechanical digestion churning muscles (tear
pieces in half)
b. Chemical digestion by acid (tear pieces in
half again)
5. Into the small intestine
a. Chemical digestion by bile (tear pieces in half
again)
b. Absorption by blood stream (I will come
around and collect some nutrients)
6. Into the large intestine
a. Absorption of water by blood stream (I will
come around and collect some water)
7. Elimination of unused food
a. Form compact feces from remaining food
particles (I will come around and collect the
feces)