Transcript The Digestive System

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The process of changing complex solids
foods into simpler soluble forms which
can be absorbed by cells.
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Enzyme – chemical substance that can
promote reactions in living things
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Alimentary canal
› Also known as the GI
(gastrointestinal tract)
› Begins with the mouth
and ends with the
anus
› Include
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Mouth
Pharynx
Esophagus
Stomach
Small intestines
Large intestine
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Accessory Organs
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Teeth
Tongue
Salivary glands
Pancreas
Liver
Gallbladder
• Connected to the GI
tract by series of
ducts
• Aid in chemical
breakdown and
absorption of food.
Accessory Organs included
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Peritoneum
› Double layered serous membrane that lines
the abdominal cavity
Physical Breakdown of food
 Chemical digestion of food into the end
products of fat, carbohydrates and
protein
 Absorb nutrients into blood capillaries of
the small intestines
 Eliminate waste products of digestion
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1 – Ingestion
› Getting food into the body
› Mouth, teeth, lips and tongue
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2 – Mechanical Breakdown
› Smaller pieces of food (chewing, churning in
stomach, churning by muscular contraction in
small intestine)
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3 – Propulsion
› Initiated by swallowing (pharynx)
› Peristalsis (symmetrical contraction of muscles
that moves food along the GI tract
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4 – Chemical breakdown
› Commonly called “digestion”
› Enzymes breakdown food
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5 – Absorption
› Movement of small molecules from small
intestine into the blood to be carried to other
parts of the body
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6 – Defecation
› Expulsion of the food that was not absorbed
through the anus.
Lips – grab food and pull
into mouth
 Tongue – contain
papillae that help to grip
food better (sense of
taste from taste buds)
 Palate (roof of mouth)
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Assist in
› Ingestion (food in
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mouth)
Mechanical breakdown
(chewing)- also called
mastication
Chemical breakdown
(enzymes in saliva)
PTYALIN- converts
starches into simple
sugars – under control of
the nervous system
Propulsion (pushing food
back to pharynx for
swallowing)
› hard and soft
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Uvula
› Keeps food out of nasal
cavity when swallowing
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Teeth and Gums
› Digestive enzymes
help to chemically
break down food
once chewing
begins
› Mastication –
process of chewing
(mechanical
digestion)
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Children have 20
deciduous
(temporary)
› Start to appear
around 6 months
› Usually all are visible
by 2 yrs of age
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Permanent teeth
begin to form
around 6 years of
age in the jawbones
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32 total (16 in
mandible and 16 in
maxilla)
As these grow, the
deciduous teeth are
pushed out
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The wisdom teeth
are generally the last
to appear, usually
late teens to early
twenties.
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Incisors
Canine
Premolars
molars
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2123 System – 2 incisors, 1 canine, 2premolars, 3 molars
Secrete saliva into the mouth via
connecting ducts. Contains mucus,
antibodies, and enzymes to help moisten
food and protect the mouth from bacterial
infection.
 Parotid (largest)- under skin, just below and
in front of the ears.
 Submandibular – medial side of the lower
back part of the mandible.
 Sublingual – under each side of the tongue.
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Food at this point is called a BOLUS
Passage way for food and air
Propulsion of food by peristalsis
Most commonly considered part of the
respiratory system
 Epiglottis at end that guides food to the
esophagus when swallowing – Remember --- Air goes to the trachea 
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Swallowing = deglutination
Flexible muscular tube that connects the
pharynx to the stomach.
 About 10 inches long
 Travels through the diaphragm
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Food is propelled through by waves of
peristalsis (muscular contraction to push
food downward)
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Located in upper more left part of abdominal cavity
filled with gastric juices.
Acidic in nature – protected by mucus membrane
› Pepsin- breaks down protein
› Hydrochloric acid destroys unwanted bacteria
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Reservoir where food is broken down both
mechanically and chemically.
Contains cardiac sphincter (top)- circular muscular
layer that controls the passage of food into the
stomach.
Pyloric sphincter (bottom) – valve that regulates the
entrance of food into the duodenum of small
intestine.
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Rugae – mucous coated lining inside the
stomach (folds of tissue)
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Peristalsis continues in the stomach
The bolus of food now is known as
CHYME – semi liquid, creamy substance
 Chyme leaves the stomach through the
pyloric sphincter
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Fundus- upper part
 Body – middle part
 Pyloric region – lower end
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Gets its name from its diameter….much
smaller than the large intestine even though
it is longer
Site of most of the chemical breakdown of
food. Food is broken down into usable
substances which can now be used by the
tissue in the body.
 Site for Absorption – in small intestine,
digested food passes into the bloodstream
and on to body cells. Undigestible parts
pass on to the large intestine.
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Duodenum – 1st segment (curves around
the pancreas.
 Is about 12 inches long
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Jejunum- 2nd section, about 8 foot long
Ileum- final portion, 10 to 12 feet in length
 Chemical digestion, absorption, and
propulsion by peristalsis occur in all three
segments of the small intestine.
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Located behind the stomach
 Secretes digestive enzyme (pancreatic
juice) into the duodenum. It travels through
the pancreatic duct and common bile
ducts to get to small intestine.
 Enzymes here help digest proteins and fats.
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It also makes the hormone insulin
(endocrine system)
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Largest organ in body
Located below the diaphragm, RUQ
Connected to gallbladder and small
intestine by ducts
Produces and stores glucose in the form of
glycogen
Detoxify alcohol, drugs and other harmful
substances
Manufactures blood proteins
Manufactures bile
Stores vitamins A, D and B complex
Small green organ, inferior surface of the
liver
 Stores and concentrates bile until it is
needed by the body
 Releases bile to help break down fatty
foods via the common bile duct
 Fat is then stored in lacteals in the intestinal
wall until needed by the body
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You can live without your gallbladder, but
you have to keep your liver 
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Larger diameter than small intestine but shorter
in length
Approximately 2 inches in diameter
Major segments – cecum, colon, rectum and
anal canal (anus)
Nutrients and water not absorbed in small
intestines are absorbed here.
Contains E. Coli (bacteria)
Main function is propulsion and elimination of
waste products not absorbed in the small
intestines
In the colon…Chyme becomes FECES
Cecum – first part in lower right portion.
 Appendix – small fingerlike projection
that extends from the cecum (not
needed). It does contain lymphocytes.
 Colon- 4 segments- Ascending colon,
transverse colon, descending colon, and
sigmoid colon
 Rectum - last portion of the colon
 Anus - external opening
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Defacation = Elimination of feces
 Flatulence = gas Bacteria causes the
odor
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Heartburn or acid reflux symptoms
include chronic cough and chest pain
and burning. Knowing your triggers, such
as certain foods, medications, obesity, or
even stress, can help prevent heartburn.
Heartburn treatment may include
medications, home remedies, or diet
changes.
 http://www.webmd.com/heartburngerd/ss/slideshow-heartburn-overview
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Gastroenteritis is inflammation of the stomach and
intestines, which leads to diarrhea and vomiting.
Gastroenteritis is most often due to a bacterial or viral
infection. Gastroenteritis that results from a virus is
called viral gastroenteritis. Many different viruses
cause gastroenteritis, including some rotaviruses,
noroviruses, and adenoviruses. Viral gastroenteritis is
contagious. Bacterial gastroenteritis is often caused
by infection with E. coli and salmonella. Other causes
of gastroenteritis include parasite infection, exposure
to harmful chemicals in seafood or water, use of
certain medications, and irritation from particular
foods.
http://www.webmd.com/children/ss/nauseavomiting-remedies-treatment
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http://www.webmd.com/digestivedisorders/tc/peptic-ulcer-disease-topicoverview
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Appendix becomes inflamed
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If it ruptures, bacteria will spread to
peritoneal cavity causing a very
dangerous infection.
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Symptoms - fever, acute pain in LRQ
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RX- surgical removal & antibiotics
Inflammation of the liver
 Types A, B, C
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http://www.webmd.com/hepatitis/ss/slid
eshow-hepatitis-overview
Cirrhosis is a slowly progressing disease in which
healthy liver tissue is replaced with scar tissue,
eventually preventing the liver from functioning
properly. The scar tissue blocks the flow of blood
through the liver and slows the processing of nutrients,
hormones, drugs, and naturally produced toxins. It
also slows the production of proteins and other
substances made by the liver.
JAUNDICE – yellow discoloration of the skin and sclera
of the eyes.
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Cholecystitis is inflammation of the gallbladder, a
small organ near the liver that plays a part in
digesting food. Normally, fluid called bile passes
out of the gallbladder on its way to the small
intestine. If the flow of bile is blocked, it builds up
inside the gallbladder, causing swelling, pain, and
possible infection.
Commonly caused by CHOLELITHIASIS
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A gallstone stuck in the cystic duct , a
tube that carries bile from the
gallbladder, is most often the cause of
sudden (acute) cholecystitis. The
gallstone blocks fluid from passing out of
the gallbladder. This results in an irritated
and swollen gallbladder. Infection or
trauma, such as an injury from a car
accident, can also cause cholecystitis.
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Diarrhea is a loose, watery bowel movement
and is not usually a serious problem in the U.S. It
can occur due to illness, intestinal problems,
food poisoning, and many others factors. It
usually goes away on its own, but you should
drink plenty of fluids and can take over-thecounter medications to help ease the
discomfort. For prolonged cases of diarrhea,
medical attention is recommended.
http://www.webmd.com/digestivedisorders/video/drossman-diarrhea-overview
Constipation is a common but painful
condition that occurs when bowel
movements become infrequent or difficult.
It can be caused by nutritional deficiencies,
stress, pregnancy, cancer, depression, and
more. The best way to prevent constipation
is eating a healthy diet, exercising, and
drinking plenty of water. Laxatives can help
relieve constipation.
 http://www.webmd.com/digestivedisorders/ss/slideshow-constipation-facts-10
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Irritable bowel syndrome or IBS affects
mostly women. Causes are unknown. IBS
symptoms include diarrhea,
constipation, and abdominal cramps. IBS
treatments include diet and lifestyle
changes and medications.
 http://www.webmd.com/ibs/ss/slidesho
w-ibs-overview
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Anorexia
› Intense fear of gaining weight
› Restrict food intake, especially those with fat
content
› Weight is 85% less than expected body
weight
› Over exercising
› Avoiding food altogether, or only allowing
minimal low calorie intake.
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Common physical signs of malnutrition from
anorexia include:
A low body weight.
Constipation and slow emptying of the
stomach.
Thinning hair, dry skin, and brittle nails.
Shrunken breasts.
Stopping or never getting a monthly menstrual
period.
Feeling cold, with a lower-than-normal body
temperature.
Low blood pressure.
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All people with anorexia need
treatment. In most cases, this involves
seeing a doctor and having regular
counseling sessions. A hospital stay is
needed for those who are seriously
underweight or who have severe
medical problems. The goals of
treatment are to restore a healthy
weight and healthy eating habits.