Keanna
Sullivan
Digestion of
Carbohydrates,
Lipids, and Proteins
Carbohydrates
1. Begins with the
mouth, the chewing
stimulates secretion of
saliva from salivary
glands. Also the chewing
breaks down the food into
smaller pieces. Salivary
amylase breaks down the
starch into smaller
polysaccharides and
maltose.
4. Liver:
Monosaccharide’s to the
liver in the bloodstream
via the portal vein. They
are converted to glucose
and transport to cells to
provide energy.
Immediate glucose is
used to provide energy.
Excess glucose is stored
as glycogen in the liver.
2. Stomach: acids destroy
salivary amylase, but no digestion
occurs in the stomach. Pancreatic
amylase is then secreted into the
small intestine.
3. Small Intestine: Pancreatic amylase breaks
down the remaining starch into maltose. Specific
enzymes in small intestine break down
disaccharides into monosaccharide. All the
monosaccharide’s are absorbed by small
intestine and then enter the bloodstream.
5. Large Intestine:
Carbohydrates pass into
the large intestine
undigested. Bacteria
break down some
undigested
carbohydrate. The
remaining fiber is
excreted in feces.
Lipids
1. Mouth: Some
digestions of lipids occur
in your mouth and
stomach but most begin
in the small intestine.
2. Stomach: Lipid
digestion begins in the
stomach with the aid of
lingual lipase and gastric
lipase.
3. Small Intestine: When chyme
enters the duodenum, the
hormonal response triggers bile.
Bile is produced by the liver and
stored in the gallbladder. The bile
salts hydrophilic side can interfere
with water while the hydrophobic
side interfaces with lipids. Lipases
break down the lipids into fatty
acids and glycerides. The
molecules then pass through the
plasma membrane of the cell.
After that they enter the intestinal
lining.
After Digestion, the fatty
acids combine with
cholesterol and bile. They
move into your cells mucosa
when they are reconverted
into the large molecules. The
large molecules pass most
vessels near the intestine.
The vessels then transport
fat to the veins in your chest.
The blood carries lipids to be
stored in adipose tissue
through your body.
Proteins
1. Mouth: Protein
digestion takes place in
the small intestine, and
stomach. Protein is found
in meat, eggs, dairy
products, fish, nuts and
beans. Before your body
can use protein to repair
tissues, enzymes called
amino acids must digest
the large molecules of
protein.
2. Stomach: hydrochloric
acid and pepsinogen, interact
to create pepsin. These two
substances are secreted by
the stomach and play an
important role in protein
digestion. Hydrolysis is the
process, which takes place
when proteins are
disintegrated by the
enzymes. Hydrochloric acid is
used for breaking the bonds
between the proteins. The
proteins are the disintegrated
into amino acids. Pepsin is
capable of digesting collagen,
which is a fibrous protein
that is one of the main
constituents of connective
tissue in animals.
3. Small Intestine: From
the stomach, protein digestion
carries on in the duodenum,
representing the first segment
of the small intestine. Pepsin
and trypsin continues the
disintegration of proteins into
amino acids in the small
intestine. Hydrolysis involves
the insertion of a water
molecule between two amino
acids, forcing eh bond
between them to break. Amino
acids are able to penetrate the
intestinal lining. They then
enter the bloodstream through
the capillaries. Amino acids
are then transporting between
various tissues depending on
which cell structures need to
be repaired or created.
4. Large Intestine:
The
protein breakdown only
happens in the stomach and
it ends in the small
intestine. The large intestine
takes up the rest of the
water and produces waste
from what is left. The body
cannot use it so nothing is
absorbed.
Summary
Absorption begins in the mouth with digestion. After food is
broken down in to tiny pieces from the enzymes in your saliva it then
travels into your stomach. There is where digestion then intensifies. It
intensifies by the action of hydrochloric acid as well as enzymes like
protease, lipase, and amylase. Protease is the enzyme that breaks
down protein. Lipase breaks down fats or lipids, and the amylase
break down carbohydrates. Next your small intestine is where
All nutrient absorption occurs. Such as protein, lipids, fat, and water.
Nutrients enter your blood through the small intestine. They either
enter through passive diffusion or active transport absorption. Calcium
and magnesium are transported actively. Depending on what nutrients
your body needs it will absorb more of. Your body thrives on
homeostasis so it is always trying to balance out which nutrients it
requires. Protein should be 10-35% of your diet. Amino acids are the
building blocks of protein. Proteins role in the body consist of repairing
and building tissues. Your diet should consist of 20% fat and 60%
carbohydrates.