Transcript Digestion And Absorption

Digestion
Digestive System
• Digestion is the process of
breaking food down into
molecules small enough for the
body to absorb.
Types of Digestion
Mechanical Digestion
• The physical breakdown of
food by teeth in the mouth,
and muscles in the
stomach.
• Chemical Digestion
• The breakdown of fats,
proteins, and complex
carbs into smaller units by
enzymes.
The Mouth
• Mechanical digestion begins
Chemical Digestion
within the Mouth (cont.)
• The salivary
glands produce
Amylase.
• Starch is digested
into its monomer
glucose.
Esophagus
Peristalsis
• A muscular tube that
connects the mouth to the
stomach.
• Peristalsis: Involuntary
waves of muscle
contractions that push food
toward the stomach.
• Mucus: is a thick slippery
substance produced by the
body. It helps make food
easier to swallow.
• The stomach also produces mucus, which
coats and protects the lining of your
stomach.
The Stomach
• Digestive juice contains
the enzyme PEPSIN.
• Pepsin chemically
digests the proteins in
your food, breaking them
down into amino acids.
• Digestive juice also
contains hydrochloric
acid. This acid helps
break down food and kills
many of the bacteria that
enters your body.
The Stomach
• Most mechanical digestion takes place in
the stomach. Three layers of muscles
mixes food with digestive juices in a
churning motion.
• As you eat your stomach will expand
between 1-2 liters to hold the food you eat.
The Small Intestine
• The small intestine is about 35 - 40 feet long.
• Almost all chemical digestion and absorption of
nutrients take place in the small intestine.
• The small intestine contains millions of tiny
finger shaped structures called villi.
Digestion of Lipids (fats)
Absorption
• Is the process by which nutrient molecules pass
through the wall your digestive tract and into the
circulatory system.
The Liver
• The largest and heaviest organ inside the body.
• The liver produces bile, a substance that breaks
up fat molecules.
• Bile flows from the liver to the gallbladder, after
you eat the gallbladder passes bile into the small
intestine.
The Pancreas
• The pancreas is a triangular organ that lies below
the small intestine.
• It produces enzymes that help break down
starches, proteins and Fats.
The Large Intestine
• The last section of the
digestive system.
• All the remaining water is
absorbed into the bloodstream.
• The remaining material is
readied for elimination.
• The large intestine ends in a
short tube called the rectum.
• The material is compressed
into solid form.
• The waste material is
eliminated from the body
through the anus.