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The Digestive System
For we are all, really, just doughnuts
J. Schwieger
Alimentary Canal
• The alimentary
canal is the mucous
membrane-lined
tube of the
digestive system.
• This is the tube
where digestion
takes place, and
from which wastes
are eliminated.
• It extends from the
mouth to the anus
and includes the
pharynx (throat),
esophagus (gullet),
stomach, and
intestines.
• It is also called
digestive tract.
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Mouth
• Teeth and saliva
begin digestion
process
• Tongue pushes
and helps to
manipulate food
so it can be
masticated
properly
• Uvula is an
extension of the
soft palate: it
helps to cover the
nasal passages
Cougar Skull
• Cougars are also
diphyodonts and
heterodonts.
• Their molars
(carnasial teeth)
overlap each other
to allow for a
scissors like cutting
action.
• The incisors are
for catching and
holding.
Wolf Skull - note the same carnasial molars. Wolves
are diphodonts as well.
Brown Bear Skull - note the crest on the skull for the
mandible muscle.
Sperm Whale
• This is the lower jaw of a
Sperm Whale on display in
a museum in Maine.
• One of the jaws on display
is 18 feet long!
• The teeth can be 6 inches
long!
• Whales teeth are all the
same. They get only one
set.
• It is estimated that this
individual was 75 feet
long and weighed 60
tons (120,000 lbs.)
Sperm Whale Juvenile Male
• This 33 foot individual was
photographed near the
Bonin islands in the
Pacific.
• Their teeth are adapted for
holding the squid and fish
they catch during their
deep, hour long dives.
• This male could grow as
long as 80-85 feet and
weigh as much as 70 tons
(140,000 lbs.)
• They are the largest
carnivore on the planet and
they have the largest brain
of any creature ever
known.
Scrimshaw
• Scrimshaw is
drawings done on
Sperm Whale teeth.
• They have become
rare and valuable
collectors items.
• These two examples
are from the JFK
museum.
• The teeth are
approximately 5
inches long.
Ivory
• Ivory is a hard, white, opaque
substance that is the bulk of the
teeth and tusks of animals such
as the elephant, hippopotamus,
walrus, mammoth and toothed
whales.
• Prior to the introduction of
plastics, it was used for billiard
balls, piano keys, buttons and
ornamental items.
• The word "ivory" was
traditionally applied to the tusks
of elephants.
• The chemical structure of the
teeth and tusks of mammals is
the same regardless of the
species.
Elephants
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In contrast to humans, elephants get 6 sets of molars.
Teeth are not, however, exchanged from the bottom to the top (vertically), as in humans and most
mammals, but rather from the back to the front (horizontally).
Elephant calves are born with approximately 2 small molar teeth, about the size of a thumbnail, in both
the upper and the lower jaw.
In the course of time the molar tooth next in size slowly moves from the back to the front and thus
replaces the old tooth.
Elephant Graveyard
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When the last tooth is worn
down, it becomes difficult
for elephants to chew their
food properly.
Then they usually start to
look around for softer
vegetation, which grows in
the swamps.
In the end old elephants
succumb to their weakness
and die at the water's edge.
Old elephants' inclination to
die in one and the same area
has enabled the rise of the
fairy tale and myth of the
elephant's graveyard.
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Elephants' tusks correspond to other
mammals' incisor teeth.
One of the tusk's unique characteristics
is that it does not have a coat of
dental enamel.
Two thirds of a tusk is visible. The
first third is lodged in the skull's tooth
socket.
Two thirds of the tusk are 'alive'. This
means that they have pulp cavities
which are filled with a tissue which
has an abundance of blood vessels and
branches of nerves.
This is why tusks are sensitive to
pressure and blows.
A tusk breaking off can have
disastrous consequences for the
elephant concerned.
In the worst case if the odontic nerve
and the pulp are exposed the animal
dies of the enormous pain.
What are tusks?
Crocodile teeth
• Teeth grow in a socket.
• If the tooth is lost a new one
will grow from an adjacent
socket.
• Once that tooth is lost it cannot
be replaced.
• Crocodiles grow continuously
throughout the lives.
• The largest ever recorded is a
specimen of the Salt Water
Crocodile.
• It was captured in a river in
Northern Australia
• It was 26 feet long and weighed
4,000 lbs.
• The jaws measured 6 feet long.
Teeth
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Enamel is composed
of CaPO4 and CaCO3
Dentin is hard and
calcified, though not
as hard as the enamel.
Connective tissue
called pulp fills the
pulp cavity within the
crown of the tooth.
The joint between the
teeth and the gums is a
fibrous joint.
Problems with teeth
include, not having a
2nd set, not having a
baby tooth, wisdom
teeth problems, decay,
cracking and breaking
and gum disease.
• Found in your mouth and
throat.
• The main ones secrete
saliva into your mouth
through ducts.
• About 1 to 1.5 L/day. 99%
is water.
• Main enzyme is amylase to
assist in the digestion of
starch. Also mucins,
lysosomes, urea and
bicarbonates to control pH
• Parotid through ducts near
upper teeth.
• Submandibular through
ducts under your tongue
• Sublingual through many
ducts in the floor of your
mouth.
Salivary Glands
Diseases of Salivary Glands
• Stones can collect and
block the ducts.
• Most common salivary
gland infection is mumps.
(parotid glands)(virus)
• Infections can pass from
lymph glands
• Cancer is rare, painful and
treatable.
Pharynx
• Common tube for food
and air (nasopharynx,
oropharynx and
laryngopharynx.)
• Epiglottis reflexively
closes over the opening
of the trachea so food
and liquids do not go to
lungs (aspiration)
• Spasm of diaphragm is
hiccups.
• Uvula – extension of
soft palate.
http://www.youtube.com/wtch?v
=Ww0YTjA1f0E
Esophagus
• Function; transport food to
stomach.
• Soft palate (uvula) closes
over nasal cavity.
• Laryngopharynx epiglottis - prevents food
from getting into lungs.
• Cardiac sphincter prevents stomach material
from backflowing into
esophagus.
• Deglutition - swallowing
• Voluntary - tongue
pushing food,
• Involuntary - esophagus
contracting to push food to
stomach.
• Not well protected from
harsh chemicals.
Esophagus
• Muscular tube
leading to stomach.
• Two layers of
muscles
longitudinal and
circular
• Peristalsiswavelike motion of
esophagus to push
food to stomach
Harmon Killebrew and Esophageal cancer
• He died of this disease last
summer.
• According to the National
Cancer Institute, there were
16,640 cases of esophageal
cancer, and 14,500 deaths
from the affliction in 2010.
• His symptoms included loss
of weight and difficulty in
swallowing.
• All the causes aren't known,
but some of the leading risk
factors for the disease
include smoking, obesity
and heavy alcohol
consumption.
• This is a disease that
commonly occurs after age
55.
• High acidity (pH =
2) allows enzyme
pepsinogen to start
protein digestion.
• Three layers of
muscles to churn
and mix the bolus.
• Does not absorb a
lot of material
(alcohol, aspirin)
• Destroys most
harmful materials.
• Specialized cells
produce alkaline
mucus to protect
itself.
• Food remains in
the stomach 3-4
hours.
• The chewed food
(bolus) becomes
chyme.
Hiatal Hernia
• A situation where
part of the stomach
extrudes above the
diaghragm.
• This can cause the
cardiac sphincter to
leak stomach fluid
into the sensitive
esophagus.
• This leakage can
cause burning,
heartburn and even
lesions or ulcers.
• Symptoms include
belching, nausea,
chest pains and
difficulty taking a
deep breath.
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At any one time, about
one in 25 adults will
have an active stomach
ulcer.
During their lifetime
one in 7 men and one
in 12 women will have
this potentially serious
condition.
Ulcers are areas of
damage to the lining of
the stomach, as in a
gastric ulcer, or the
upper part of the
intestine (duodenal
ulcer).
A number of factors
cause ulcers.
These include
prolonged use of antiinflammatory drugs
(often used to treat
arthritis), smoking,
alcohol, diet and
stress.
Ulcers
Ulcers
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The symptom of an
ulcer is pain in the
upper part of the
abdomen just below the
breast bone.
The pain generally
occurs when the
stomach is empty.
The pain is often
relieved by food or
antacid medication.
More serious symptoms
occur if the ulcer bleeds.
On rare occasions an
ulcer will perforate
through the stomach or
duodenal wall. This is a
major emergency
requiring surgery.
Most ulcers respond
well to treatment with
drugs which heal them.
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This is a bacterial organism that
is responsible for many stomach
diseases.
It enters the body through
infected food and the bacterium
hides in the mucus layer of the
stomach protecting itself against
the low pH of the stomach.
With stomach ulcers, H. pylori
infection is found in 60 to 80
percent of the cases.
It is still uncertain how the
infection acts to cause the ulcer.
It probably weakens the
protective mucous layer of the
stomach.
This allows acid to seep in and
injure the underlying stomach
cells.
There is still a great deal of
research to be done to unravel
this relationship.
Heliobacter pylori
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A large fold of
connective tissue that
hangs down over the
intestines and
interconnects the
stomach, duodenum
and the large intestine.
It can have lots of
adipose tissue (fatty
apron)
Contains lymph nodes
which help fight
infection and prevent
its spread to the
peritoneum.
Falciform ligament,
attaches the liver to the
diaphragm.
Lesser omentum
suspends to stomach
and the first part of the
duodenum
Greater Omentum
• The diaphragm
is a thin domeshaped muscle
which separates
the thoracic
cavity (lungs
and heart) from
the abdominal
cavity
(intestines,
stomach, liver,
etc.).
• It is involved in
respiration,
drawing
downward in the
chest on
inhalation, and
pushing upward
in exhalation.
Diaphragm
• Elongated organ containing
exocrine (ducted) and
endocrine glands.
• Exocrine - digestive
enzymes through
pancreatic duct into the
duodenum.
• Endocrine - insulin which
is produced from cells in
the pancreas called the
islets of Langerhans
• Insulin helps the cells of
the body absorb glucose
from the blood.
• In the absence of insulin
glucose levels in the blood
increase to dangerous
levels and the excess has to
be removed via the
kidneys. This disease is
called diabetes.
Pancreas
• Endocrine cells which
produce insulin.
• For some reason, which
seems to have a genetic
tendency, these cells stop
producing insulin in some
people.
• This usually occurs in
young children and teens.
• This is called Juvenile
onset Diabetes.(Type 1
Diabetes)
• These people afflicted
with this disease will
need to take insulin the
rest of their lives.
• Fortunately there is plenty
of human insulin made
available through genetic
engineering.
Islets of Langerhans
• There are 18.2 million
people in the United
States have diabetes.
• An estimated 13 million
have been diagnosed,
• Type 2 diabetes is the
most common form of
diabetes.
• In type 2 diabetes, either
the body does not
produce enough insulin or
the cells ignore the
insulin.
• New technology like the
insulin pump pictured
here allows the diabetic to
do a better job of
maintaining a constant
blood sugar level.
• The hope for the future
may be in the success of
transplanting islets of
Langerhans cells.
Diabetes
Liver
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Largest gland of
body (1500 g)
Removes excess
nutrients from blood,
transforms glucose to
glycogen or fat.
Synthesizes plasma
proteins and blood
clotting proteins
Detoxifies alcohol
and other poisons
Destroys bacteria
and old RBC’s
Helps to activate
vitamin D.
It stores iron, copper,
and certain vitamins
(A, D, E, K. B12)
Hepatocyte – stores glycogen, Vit. A, B12, and Fe. Makes plasma proteins,
metabolizes fat soluble compounds (drugs, insecticides). Secretes bile (1
L/day)
Kupffer cells - specialized cells in the liver that destroy bacteria, foreign
proteins, and worn-out blood cells.
Stellate cells – when activated produce collagen and scar tissue for an injured
liver.
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A chronic liver disease which
damages liver tissue.
• This includes scarring of the
liver (fibrosis; nodular
regeneration), progressive
decrease in liver function,
excessive fluid in the
abdomen (ascites), bleeding
disorders (coagulopathy),
increased pressure in the
blood vessels (portal
hypertension), and brain
function disorders (hepatic
encephalopathy).
• Excessive alcohol use is the
leading cause of cirrhosis.
• Cirrhosis is a serious
condition. Only 30 per cent
of patients with this problem
will survive five years after
diagnosis and the outlook is
worse if the cause is alcohol
and the patient continues to
drink.
Cirrhosis of the Liver
Live donor liver transplantation (LDLT) is a procedure in which a living person donates a
portion of his or her liver to another. LDLT was first demonstrated in the United States in
1989. The recipient was a child, who received a segment of his mother's liver..
Liver Recipients
• Patients being considered
for LDLT are those who are
candidates to receive a
cadaveric liver.
• These patients are placed on
the liver transplant waiting
list and will not be denied a
donor liver if it becomes
available prior to LDLT.
• Thus, failure to find a
suitable donor for LDLT will
not jeopardize the recipient's
chances of receiving a
cadaveric liver
Basic Facts about the liver donor
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The donor could either be a
relative or even unrelated.
The blood type should be the
same as the recipient's.
The donor should be in good
physical and mental health.
The decision to be a donor
should be made after careful
consideration of facts and
knowledge of the
procedures, the risks and
complications.
The donor must be relatively
close in size (or larger) than
the recipient.
It is rare, but not unheard of
for a donor to die during this
process.
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A good donor is someone
who is in good physical and
mental health, older than the
age of 18 and free from:
• HIV infection
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Known viral hepatitis
Active alcoholism with
frequent and heavy alcohol
intake
Psychiatric illness under
treatment
History of malignancy
Heart and lung disease
requiring medications
Diabetes mellitus of greater
than 7 years duration
Liver
donors
Donor Recovery
• The donor is in the intensive
care unit for about 24 hours
and in the hospital for 5-7
days.
• Most patients are up and out
of bed (with assistance) by
the second or third
postoperative day.
• It is necessary to stay off
work and usual home
activities for a month full
time.
• After that, 2 to 4 weeks part
time, depending on the
rapidity of the recovery.
• After 3 months donors are
living a normal life.
Performing the Operation
• Two teams perform the
donor and recipient
operations simultaneously.
• As the diseased liver is
removed from the recipient
by one team, approximately
half of the donor's normal
liver is removed by the other
team.
• Once the donor operation is
completed, both teams
complete the transplant by
attaching the half-liver into
the recipient.
• The donor operation takes
about 5 hours and the
recipient operation about 10
hours.
• Both half-livers (of donor
and recipient) grow to be full
Recipient Recovery
• After 2 days in intensive care
the recipient stays in the
hospital for another 10 days.
• For the first few weeks
frequent checks are needed.
• Weekly lab work is done for
the first 4 months.
• Liver transplantation requires
a lifelong commitment by the
patient and family.
• This includes taking
medications daily, visiting a
physician regularly, eating a
proper diet, maintaining an
exercise program and trying
to avoid infections.
• Holly Werlein, 25 liver
recipient
Holly’s story – part 1
• I never thought in a million years that I would go
through something like this. My story isn't like most
peoples who unfortunately had to wait. I am one of
the rare few that went through acute fulminate liver
failure. I just happened to be in the right place at the
right time. I was at the Cleveland Clinic for a totally
unrelated appt. and my mom noticed my eyes were
yellow. I hadn't been feeling all the best, upset
stomach, fatigue and just figured it was nothing. Well
my doctor had my liver enzymes tested and they
were in the thousands, so she immediately admitted
me. I thought this was crazy! They tested me for
everything possible and couldn't find anything wrong.
Holly’s story part 2
• Our 2 day trip turned into an unexpected month long
stay at the hospital. I remember 3-4 days in the
hospital and the rest is vague memories, until I woke
up! I had no idea I had a liver transplant! Apparently,
my parents told me, I was telling docs I was in
Florida. They thought my liver was going to
regenerate since I was so young, but the toxins
continued to build up and finally docs realized that
after a liver biopsy. I was immediately put on the list
1st in the nation for a liver. Miraculously, they found
one in 8 hours and I was transplanted with no time to
spare. It's amazing how quickly this all happened and
they never figured out the cause of my liver failure,
which is scary. They said it had shrunk to 1 lb and
had brown spots on it, which is weird.
Holly’s story part 3
• My recovery was quick at first, but I went through
good old rejection about 2-3 weeks after. I had to be
airlifted from Michigan back to Cleveland. They put
me on high dose IV steroids for 2 weeks and by then
I was ready to get out of there. Ever since that
episode, I've been doing well and have participated in
the US and world transplant games. My family has
been my rock and I'm so thankful for them and each
day that I am alive! However, the realization process
for me has been hard at times. I feel like I'm
dreaming. It was a completely unexpected change of
life for me and it still feels surreal that it even
happened.
Holly’s story - conclusion
• The Gift of Life is so amazing and we are all true
miracles! I’m so happy to be alive and so thankful for
my donor! I'm really into being a donor advocate and
like to share my experience with others. I feel I'm
alive to help do as much as I can to promote organ
donation.
Small Intestine - starts at the pyloric sphincter and ends at the ileocecal sphincter.
• First part of small intestine
is the duodenum (22 cm).
• Receives ducts from the
liver and pancreas. (The
common bile duct)
• This is where most of the
digestion of foods takes
place.
• pH is now above 7 thanks
to the secretion of
NaHCO3 secreted by the
pancreas.
• Digestive enzymes come
from the pancreas.
• The rest of the small
intestine is involved in
absorption of nutrients
Small Intestine
• Parts include the
duodenum, jejunum
ileum and ileocecal
sphincter
• Duodenum completes
digestion of
fats,proteins,
carbohydrates and
nucleic acids
• The small intestine
absorbs fatty acids,
amino acids, glucose
and minerals.
Large Intestine
• Parts include the
cecum (appendix),
ascending colon,
transverse colon,
descending colon,
sigmoid colon,
rectum,internal and
external anal
sphincters
Large Intestine
• The large intestines
main functions include
the absorption of
vitamins, water and
minerals
• Material is moved
through by peristalsis
• NaHCO3 reduces
acidity
• Mucus helps to
lubricate the waste
• Waste is passed at
least every 24 hours
Large Intestine
• Bacteria in the large
intestine help to
digest certain
carbohydrates that
the body cannot. (I.e.
raffinose)
• Bacteria will
produce waste gases
that are passed out as
flatus
• Certain foods (beans,
nuts have lots of
raffinose
• Flexible sigmoidoscopy is a
procedure using a small,
flexible tube with a fiberoptic
camera and light attached to its
tip to look into the rectum
and the colon.
• The end of the scope can be
bent to pass around corners.
• Using a sigmoidoscope, a
doctor can look into the last
two feet of the colon for signs
of cancer, polyps,
diverticulosis or colitis
• The American Cancer
Society recommends that from
age 40 on, individuals should
receive an annual rectal exam.
• After age 50 individuals should
have their stool tested for
blood annually and should
have a flexible sigmoidoscopy
every three to five years.
Flexible Sigmoidoscopy
• Colonoscopy lets the doctor
see the lining of your large
intestine (rectum and colon).
• Using a thin flexible
telescope (colonoscope), the
doctor can look inside your
colon for problems such as
swellings, tumors or growths
(polyps).
• The doctor can remove some
samples (biopsies) for
laboratory analysis.
• Can treat some lesions (such
as polyps) at the same time.
• Because of the more invasive
nature of this procedure the
patient is given a general
anesthetic.
• The colon must be empty and
clear before the procedure.
Colonscopy
Colonscopy images
• A polyp* is extra tissue that
grows inside your body.
• Colon polyps grow in the
large intestine.
• Most colon polyps are not
dangerous. Most are benign,
which means they are not
cancer.
• But over time, some types of
polyps can turn into cancer.
• Usually, polyps that are
smaller than a pea aren't
harmful.
• Larger polyps could someday
become cancer or may
already be cancer.
• To be safe, doctors remove
all polyps and test them
Colon polyps
• This is a small gland
under your sternum
that is actually a part
of lymphatic system
• Helps to produce
white blood cells
• It is most active in
teenagers and shrinks
in adults.
Thymus
Appendix
• Blind ending of the
large intestine.
• Has no known
functions, perhaps
an immune
function
• Appendicitis is
most common
childhood
abdominal
operation.
Morbid obesity
• A disease that seems to
have genetic links.
• Some people gain weight
even when they eat a little.
• One strategy is to restrict
the size of the stomach.
• The other strategy is to
restrict the ability of the
system to digest and
absorb food.
Lab-Band procedure
• In this procedure an
inflatable silicone band is
placed around the upper part
of the stomach to create a
small pouch.
• The outlet from the pouch is
restricts the emptying of the
food and thus creates the
feeling of fullness
Lab-Band surgery before and after pictures
Intestinal bypass
• 1954 - This was the first
attempt at surgically induced
weight loss.
• Also referred to as the "J-I
bypass," this procedure
excluded most of the small
intestine from the flow of
food.
• It was intended to produce
malabsorption and was
associated with many
complications such as severe
diarrhea, electrolyte
imbalances, kidney stones,
and liver failure.
• This operation is no longer
in use.
Gastroplasty
More commonly known
as "stomach stapling."
• There were many different
variations of stomach
stapling.
• The most commonly
performed was the
"Horizontal Gastroplasty"
which was developed in
1979 at Ohio State
University.
• These types of operations
were plagued by failures
of the staple lines and
have mostly been
abandoned.
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• The upper part of the
stomach is divided using an
automatic stapling device.
• This creates the small
stomach pouch
(approximately the size of a
small egg).
• The small intestine is then
divided and re-connected to
the remaining small
intestine about three feet
below the point of division.
• This connection, called the
Roux-en-Y anastamosis, is
seen in the diagram to the
right.
• The stomach, duodenum,
and several feet of upper
small intestine are bypassed.
Roux-en-Y Gastric Bypass