2. MAIN FUNCTION OF THE
DIGESTIVE SYSTEM
•Digestion- the process by which your
body breaks down the food you eat
into substances that it can take
absorb (take in) and use.
3. ORGANS OF THE DIGESTIVE
SYSTEM
MAIN ORGANS
• Mouth (Oral Cavity)
• Pharynx
• Esophagus
• Stomach
• Small Intestine
• Large Intestine (Colon)
• Rectum
• Anus
ACCESSORY ORGANS
• Teeth and Tongue
• Salivary Glands
• Liver
• Gallbladder
• Pancreas
• Appendix
5. MOUTH (ORAL
CAVITY) • The mouth is where food enters
or is ingested into the digestive
tract and the process of
digestion begins.
• The roof of the mouth is formed
by the hard and soft palates and
hanging down from the center of
the soft palate is the uvula. The
soft palate and the uvula, in
most circumstances, prevent any
food or liquid from entering the
nasal cavities above the mouth.
• The floor of the mouth consists
of the tongue and its muscles.
• The mouth also consists of the
teeth (20 baby teeth and 32
6. SALIVARY GLANDS
• As we chew, the salivary glands
around the mouth produce
saliva that softens the food so
it is easier to swallow.
• Saliva also contains enzymes
that start to break down and
digest the food.
• These glands are located
outside of the digestive tube
itself and must convey their
secretions by ways of ducts
into the track.
7. SWALLOWING
• Swallowing occurs when
you push some chewed
food towards the back of
your mouth.
• As you swallow, two
involuntary events occur:
• The soft palate is
pressed upwards to stop
food from getting into
your nose.
• The epiglottis (flap of
cartilage at the top of
the windpipe), tilts down
over the larynx to stop
8. PHARYNX
•Tube-like structure found in
both the respiratory and
digestive systems.
•Because of its location
behind the nasal cavities and
mouth, it functions as part of
the respiratory and digestive
systems.
•Air must pass through the
pharynx on its way to the
lungs and food must pass
9. ESOPHAGUS
•Muscle-lined tube that
connects the pharynx to
the stomach.
•The esophagus is about
9-10 inches (25
centimeters) long and less
than an inch (2
centimeters) in diameter
10. STOMACH
after it has been chewed, swallowed,
and passed through the esophagus.
• The sight, smell, and taste of food all
start the production of gastric juices
so that by the time the food reaches
the stomach, it is ready to start
digestion.
• The gastric juices produced by the
stomach contain acid and enzymes
that break down proteins.
• Once the food has been reduced to a
liquid, the muscular ring at the exit of
the stomach relaxes and the liquid
enters the small intestine.
• The mixture of churned food and
gastric juices that leaves the stomach
is called chyme.
• Stomach muscle contractions result in
peristalsis, which propels food down
11. distinct regions:
1. Duodenum- mixes the chyme
with enzymes and bile to break it
down into molecules small
enough to be absorbed
2. Jejunum- where food is
absorbed
3. Ileum- absorbs vitamin B12
• The part of the gastrointestinal
tract between the stomach and the
large intestine where most of the
end absorption of food takes
place.
• Facts:
• Roughly 7 meters (20 feet long)
• Lined with protective mucus
• Lining also consists of
thousands of folds and tiny
projections called villi
• The primary function of the small
intestine is the absorption of
nutrients and minerals from food.
• Once all of the useful molecules
SMALL
INTESTINE
12. LARGE INTESTINE FACTS AND ANATOMY
FACTS:
• The large intestine performs
the vital functions of
converting food into feces,
absorbing essential vitamins
produced by gut bacteria,
and reclaiming water from
feces.
• About 1.5 meters (five feet
long), but much larger
diameter than small
intestine.
• It will process over 50 tons of
consumed items over a
lifetime.
• Waste products can stay
ANATOMY:
13. LARGE INTESTINE
• Chyme enters the large intestine from the small intestine.
• Chyme passes through the cecum where it is mixed with beneficial bacteria that
have colonized the large intestine throughout a person’s lifetime.
• The chyme is then slowly moved through the four regions of the colon.
• Most of the movement of chyme is achieved by slow waves of peristalsis over a
period of several hours, but the colon can also be emptied quickly by stronger
waves of mass peristalsis following a large meal.
• While chyme moves through the large intestine, bacteria digest substances in the
chyme that are not digestible by the human digestive system.
• Bacterial fermentation converts the chyme into feces and releases vitamins
including K, B1, B2, B6, B12, and biotin.
• Vitamin K is almost exclusively produced by the gut bacteria and is essential in the
proper clotting of blood.
• Gases such as carbon dioxide and methane are also produced as a byproduct of
bacterial fermentation and lead to flatulence, or gas passed through the anus.
• The absorption of water by the large intestine not only helps to condense and
solidify feces, but also allows the body to retain water to be used in other
14. THE APPENDIX
• The appendix is a cul-de-sac of
a tube connected to your cecum.
• For years, many said the
appendix had no purpose, but
recent studies have found that
the appendix may in fact act as a
reservoir for good bacteria.
• These bacteria contribute to
keeping the gut healthy and
helping you recover from
infections.
15. THE RECTUM AND ANUS
• The rectum and anus are the final stages of
the digestive tract.
• The rectum is the last straight section of
the large intestine before reaching the
anus. The rectum is an 8-inch chamber
that connects the colon to the anus. It is
the rectum's job to receive stool from the
colon, to let the person know that there is
stool to be evacuated, and to hold the stool
until evacuation happens. When anything
(gas or stool) comes into the rectum,
sensors send a message to the brain. The
brain then decides if the rectal contents
can be released or not.
• The anus is the last part of the digestive
tract. It is a 2-inch long canal surrounded
by sphincter muscles that are important in
17. THE LIVER
• The biggest internal organ is
the liver.
• Functions of the liver:
• Breakdown of lipids and
fat
• Breaks down
• Remove toxins
• Recycles red blood cells
and makes new plasma
• Regulates blood glucose
levels
• Stores vitamins and
minerals
• Produces and secretes bile
(a yellowish or greenish
bitter liquid that helps
dissolve fat as food is
18. THE GALLBLADDER
• A small hollow bag that lies behind the
liver and stores the bile.
• It is connected to the common bile
duct by the cystic duct and the
common bile duct connects the liver to
the small intestine.
• Bile is released into the small intestine
when we eat and helps in the digestion
of fats.
• Bile contains a fatty material called
cholesterol. If there is too much
cholesterol in the bile, it may start to
turn solid and form lumps called
gallstones.
• Some people with gallstones have their
gall bladder removed (you do not need
a gallbladder to live), but these people
may have to go on a very low fat diet
as they cannot digest fats properly.
19. THE PANCREAS
• A large, carrot-shaped gland that lies just
below your stomach.
• Main function of the pancreas is to secrete
insulin to break down sugars.
• It also produces enzymes or digestive juices,
which are secreted into the small intestine to
further break down food after it has left the
stomach.
• The pancreas secretes the body’s own
antacid, sodium bicarbonate to settle an
upset stomach.
• The head of the pancreas is on the right side
of the abdomen and is connected to the
duodenum (the first section of the small
20. LABEL THE DIGESTIVE SYSTEM DIAGRAM
• 1. Mouth (Oral
Cavity)
• 2. Liver
• 3. Gallbladder
• 4. Large Intestine
• 5. Appendix
• 6. Anus
• 7. Esophagus
• 8. Stomach
• 9. Pancreas
• 10. Small Intestine
22. WHAT’S MY PROBLEM?
• You are going to receive a worksheet.
• Your job? Correctly identify15 common digestive
system ailments.
• Read the directions on the worksheet and begin!
• We will check our work after.