Download Digestion and Absorption

Digestion and Absorption
Digestion
• Digestion-The bodily process of breaking
food down into simpler compounds the
body can use.
• The Digestive Tract- a tube, about 30 feet,
that extends from the mouth to the anus. It
contains the esophagus, the stomach, and
the small and large intestine. These parts
work together to both mechanically and
chemically help the body use food.
The Digestion Process
• 2 phases- Mechanical and Chemical
• Mechanical- Begins in the mouth.
1.Teeth chew and break down food.
2.Contractions of the muscular walls of the
digestive tract carry on the mechanical action.
These contractions mix food particles and break
them into smaller pieces.
3.Waves of contraction, peristalsis, the muscles
push food through the digestive tract.
* Emotions such as sadness, depression and fear
can slow this process down. Anger and
aggression can speed up this process.
The Digestion Process
• Chemical Phase1. Also begins in the mouth. As you chew food is
mixed with saliva, an enzyme-containing liquid.
Saliva moistens the food partials and begins to
break down starches.
2. In the stomach, gastric juices containing
hydrochloric acid are secreted. These juices
break down food further. * Carbohydrates
leave the stomach first, Proteins are second,
followed by fats. As a result you will feel
hungry sooner after a meal high in Carbs.
The Digestion Process
• 3. Next the food leaves the stomach and enters
the small intestine. Here several juices intestinal,
pancreatic, and bile break down the food.
• 4. Then indigestible residues, bile
pigments, other waste and water travel
into the large intestine. The large intestine
acts as a storage area. Eventually the
body will excrete these material in the
feces.
The Absorption Process
• The body can absorb water, ethyl alcohol,
and simple sugars directly from the
stomach. They pass through the stomach
walls and into the bloodstream. However,
most absorption takes place in the small
intestine through capillaries.