2. Digestive Enzymes
These exist in the alimentary Digestion is the process of
tract making food absorbable by
Purpose - breaking down dissolving it into simpler
components of food so that chemical components. This
they can be absorbed by the occurs in the body chiefly
body. through the action of
The main sites of action are digestive enzymes.
the oral cavity, the stomach,
the duodenum and the Enzymes are “molecular machines that do useful
jejunum. work. Some manufacture large, complex molecules
for use in the cell. Others take molecules apart,
They are secreted by different
breaking them down into their raw material to be
glands: the salivary glands, recycled.”
the glands in the stomach, - Hari Sharma, MD
the pancreas, and the glands
in the small intestines.
3. Ailmentary
Tract
Includes the
Upper and Lower
Gastrointestinal tract
http://en.wikipedia.org/wiki/Alimentary_tract
4. The Mouth Starts
Everything Moving
Even before you eat, when Your tongue helps out,
you smell a tasty food, see pushing the food around
it, or think about it, while you chew with your
digestion begins. teeth.
Saliva begins to form in When you're ready to
your mouth. When you do swallow, the tongue
eat, the saliva breaks pushes a tiny bit of
down the chemicals in the masticated food called a
food a bit, which helps bolus toward the back of
make the food mushy and your throat and into the
easy to swallow. opening of your
esophagus, the second
part of the digestive tract.
6. Oral Cavity
In the oral cavity, salivary glands secrete ptyalin.
It is a type of amylase, which digests starch into
small segments of multiple sugars and into
individual soluble sugars.
Secreted by small and large salivary glands.
Salivary glands also secrete lysozyme, which kills
bacteria but is not classified as a digestive enzyme.
7. The Esophagus
http://www.plwc.org/oncology_content/content_images/esophagus_credit_large.jpg
The esophagus is like a stretchy pipe that's about 10 inches (25
centimeters) long.
It moves food from the back of your throat to your stomach. But also
at the back of your throat is your windpipe, which allows air to come in
and out of your body.
8. Esophagus
When you swallow food or liquids, a special flap called the
epiglottis covers over the opening of your windpipe to
make sure the food enters the esophagus and not the
windpipe.
If you've ever drunk something too fast, started to cough,
and heard someone say that your drink "went down the
wrong way," the person meant that it went down your
windpipe by mistake. This happens when the epiglottis
doesn't have enough time to flop down, and you cough
involuntarily to clear the windpipe.
Once food has entered the esophagus, it doesn't just drop
right into the stomach. Instead, muscles in the walls of the
esophagus move in a wavy way (peristaltia) which slowly
squeezes the food through the esophagus. This takes about
2 or 3 seconds.
9. Stomach
Your stomach is
attached to the end of
the esophagus.
It has three important
jobs:to store the food
you've eaten; break
down the food into a
liquidy mixture; and
slowly empty that
mixture into the small
intestine.
http://www.bupa.co.uk/health_information/images/organ/stomach.gif
10. Stomach
The stomach is like a mixer, churning and mashing
together all the small balls of food that came down
the esophagus into smaller and smaller pieces. It does
this with help from the strong muscles in the walls of
the stomach and gastric juices that also come from
the stomach's walls.
In addition to breaking down food, gastric juices also
help kill bacteria that might be in the eaten food.
The enzymes that get secreted in the stomach are
called gastric enzymes.
11. Enzymes in the Stomach
Pepsin is the main gastric
enzyme. It breaks proteins Pepsin in complex with pepstatin
into small peptide fragments,
it is a peptidase.
Gelatinase, degrades gelatin
and collagen, which are the
proteoglycans found in meat.
Gastric amylase degrades
starch, but is of minor
significance.
Gastric lipase is a tributyrase
by its biochemical activity, http://en.wikipedia.org/wiki/Pepsin
because it acts almost
exclusively on tributyrin, a
butter fat
12. Pancreas
The pancreas is the main
digestive gland in our body.
It secretes many different
enzymes - proteases,
nucleases and an amylase
http://en.wikipedia.org/wiki/Pancreas
13. Pancreatic enzymes
Trypsin, is a peptidase, like pepsin in the stomach.
Chymotrysin, is also a peptidase.
Steapsin, is a carbohydrate digesting enzyme.
Carboxypeptidase splits peptide fragments into individual
amino acids. It is a protease.
Several elastases degrade the protein elastin and other
proteins.
Several nucleases degrade nucleic acids, like DNAase and
RNAase.
Pancreatic amylase, besides starch and glycogen, degrades
also most other hydrocarbons, but not cellulose . Forming
disaccharides and trisaccharides.
Bile from the Liver, emulsifies fat, allowing more efficient
use of the lipase enzyme in the duodenum. This converts
lipids to their component fatty acid and glycerol molecules.
14. The Small Intestine
The small intestine is a long tube that's about 1 1/2 inches to 2 inches
(about 3.5 to 5 centimeters) around, and it's packed inside you beneath
your stomach. If you stretched out an adult's small intestine, it would be
about 22 feet long (6.7 meters).
The small intestine breaks down the food mixture even more so your body
can absorb all the vitamins, minerals, proteins, carbohydrates, and fats
from your food. The small intestine can help extract them - with a little
help from the pancreas, liver, and gallbladder.
These organs send different juices to the first part of the small intestine.
The juices help to digest food and allow the body to absorb nutrients. The
pancreas makes juices that help the body digest fats and protein. -
pancreatic enzymes.
Your food may spend as long as 4 hours in the small intestine and will
become a very thin, watery mixture. The nutrients from food can pass
from the small intestine into the blood stream.
Once in the blood, your body is closer to benefiting from complex
carbohydrates, vitamins, proteins, and minerals. The next stage in
digestion is the liver. And the leftover waste - remnants of the food that
your body can't use - goes on to the large intestine.
15. Small Intestine
http://en.wikipedia.org/wiki/Jejunum
The jejunum and ileum secretes a juice called succus
entericus which contains six types of enzymes that degrade
disaccharides into monosaccarides - these are considered
peptidases.
16. Peptidases - enzymes
Sucrase, breaks down sucrose
Sucrose, a common disaccharide
into glucose and fructose
Maltase, breaks down maltose
into glucose.
Isomaltase, breaks down maltose
and isomaltose
Lactase, breaks down lactose into
glucose and galactose
Intestinal lipase, breaks down
fatty acids
Erepsin, is a protein-digesting
enzyme
http://en.wikipedia.org/wiki/Digestive_enzyme
17. Liver and Gallbladder
Nutrient-rich blood comes directly The gallbladder serves as a
to the liver for processing. warehouse for bile, storing it
A juice from the liver called bile until the body needs it.
helps to absorb fats into the
bloodstream.
The liver filters out harmful
substances or wastes, turning some
of the waste into more bile.
The liver even helps figure out how
many nutrients will go to the rest
of the body, and how many will
stay behind in storage. For
example, the liver stores certain
vitamins and a type of sugar your
body uses for energy.
http://www.britishlivertrust.org.uk/content/liver/images/liver-biliarytract.gif
18. Large Intestine
At 3 or 4 inches around (about 7
to 10 centimeters), the large
intestine is fatter than the small
intestine and it's almost the last
stop on the digestive tract. Like
the small intestine, it is packed
into the body, and would measure
5 feet (about 1.5 meters) long if
you spread it out.
The large intestine has a tiny tube
with a closed end coming off it
called the appendix. It's part of
the digestive tract, but it doesn't
seem to do anything, though it
can cause big problems, because
it sometimes gets infected and
needs to be removed.
The large intestine, or colon, may
be divided into the cecum,
http://www.becomehealthynow.com/popups/lrg_intest.htm ascending colon, transverse
colon, descending colon, and
sigmoid colon.
19. Digestive Waste
After most of the nutrients are removed from the digested
food, there is waste left over - stuff your body can't use.
This becomes feces.
This passes through the part of the large intestine called
the colon - which is where the body gets its last chance to
absorb the water and some minerals into the blood.
As the water leaves the waste product, what's left gets
harder and harder as it keeps moving along, until it
becomes a solid.
The large intestine pushes the feces into the rectum, the
very last stop on the digestive tract. The solid waste stays
here until the body is ready to make a bowel movement-
pushing it through the anus
20. A Healthy Digestive System
You can help your digestive system by drinking plenty
of water and eating a healthy diet that includes
organic, fresh foods rich in fiber.
High-fiber foods, like fruits, vegetables, and whole
grains, make it easier for digested food to pass
through your system and keeps your colon healthy.
The digestive system is a very important part of your
body. Without it, you couldn't get the nutrients you
need to grow and repair properly or stay youthful and
healthy.
