Transcript liver, gall bladder & pancreas © 2006 Plano ISD, Plano, TX

© 2006 Plano ISD, Plano, TX
Digestive System
a coiled, muscular tube (6-9 meters
long) beginning with the mouth and
ending with the anus
The main role of the digestive system is
to break down and absorb nutrients that
are necessary for growth and
maintenance.
© 2006 Plano ISD, Plano, TX
The Path of Digestion
•
•
•
•
•
•
•
Mouth
Esophagus
Stomach
Small intestine
Large intestine
Rectum
Helpers are:
liver, gall
bladder &
pancreas
© 2006 Plano ISD, Plano, TX
Digestion
process by which food is converted
into soluble forms
2 forms of digestion
physical or
mechanical
© 2006 Plano ISD, Plano, TX
chemical
Forms of Digestion
Physical Digestion
Chemical Digestion
 mechanical
 chemical
breakdown of food
breakdown of food
into smaller particles by enzymes
 begins in mouth
 begins in mouth
with saliva
by chewing – teeth
and tongue
 increases surface  mostly occurs in
area of food
small intestine
© 2006 Plano ISD, Plano, TX
Physical Digestion
 mechanical
 begins in mouth
by chewing
© 2006 Plano ISD, Plano, TX
Chemical Digestion
 chemical
 begins in mouth
with saliva
Stages of Digestion

movement propels food through system

secretion


breakdown of food into
molecular sizes
food molecules passing
absorption
through intestinal walls

elimination removal of undigested food
release of digestive juices
digestion
© 2006 Plano ISD, Plano, TX
Primary
Digestive Organs
© 2006 Plano ISD, Plano, TX
begin the
mechanical
breakdown of
food
esophagus - transports
food to stomach through
the process of
stomach - muscular
peristalsis
organ that stores,
mixes, digests and
controls passage of
food
teeth
mouth
tongue
© 2006 Plano ISD, Plano, TX
Esophagus
• Moves food from the back of throat to the
stomach
• Epiglottis – flap of skin that covers
windpipe (trachea), keeping food out of
lungs
• Valve at the end of the esophagus
(sphincter) allows food to pass into the
stomach but not back into the esophagus
• Takes about 8-10 seconds to move bolus
(chewed food) from swallowing to stomach
© 2006 Plano ISD, Plano, TX
Peristalsis
esophagus
food
stomach
© 2006 Plano ISD, Plano, TX
series of
involuntary
muscular
contractions
in the
esophagus
that
squeeze the
food down
to the
stomach
From the esophagus to the
Stomach
Click on picture to show video
© 2006 Plano ISD, Plano,http://www.gastrointestinalatlas.com
TX
Stomach
• Muscular walls of stomach contract to
churn and mix the food with gastric
juices
• Gastric juices (hydrochloric acid and
pepsin with mucus) - begin the break
down of proteins
• Chemical and mechanical digestion
takes about 2 to 3 hours
• Mixture of partially digested food is
called chyme
© 2006 Plano ISD, Plano, TX
small intestines coiled tube from 3 6m long, the major
site for digestion and
absorption of
nutrients; contain villi
large intestines 1.5 m long tube,
absorbs water from
undigested material
anus - opening for
removal of feces
© 2006 Plano ISD, Plano, TX
Small Intestine
• Chyme is flooded with enzymes
• Enzymes help break down the
nutrients to basic forms
• Liver produces bile (stored in the
gall bladder) – a salt that helps
break down fats
• Villi - finger like projections in
the wall of the small intestines
where blood vessels absorb
nutrients into the bloodstream
© 2006 Plano ISD, Plano, TX
Large Intestine
• Undigested material (fiber, water,
and un-digestible substances) moves
into the large intestine or colon
• Water is removed and undigested
material reduced to a solid waste
called feces
• Colon contains bacteria to help final
digestion
• Feces (yes, poop) is stored in the
rectum and eliminated
© 2006 Plano ISD, Plano, TX
Elimination
• Undigested waste is
moved into the
rectum where it is
eliminated through
the anus
• Peristalsis – the
muscular
contractions that
move food through
your digestive system
© 2006 Plano ISD, Plano, TX
Accessory
Digestive Organs
© 2006 Plano ISD, Plano, TX
salivary glands secrete a chemical
(enzyme) that breaks
down
into bile,
produces
liver -starch
glucose
which helps break down
fats in small intestines
gall bladder - stores bile
© 2006 Plano ISD, Plano, TX
pancreas - secretes
enzymes that break
down starches and
proteins
The Liver (& Gall Bladder)
• Liver produces bile to help with chemical
digestion
• Bile stored in the gall bladder (then sent to
beginning of small intestine)
• The liver filters harmful substances or
wastes, turning some of the waste into
more bile
• The liver 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.
© 2006 Plano ISD, Plano, TX
Accessory Digestive Organs
connected to stomach by ducts
liver
pancreas
gall bladder
© 2006 Plano ISD, Plano, TX
Pancreas
• Produces some
digestive
enzymes
© 2006 Plano ISD, Plano, TX
© 2006 Plano ISD, Plano, TX
ulcers
spot in stomach lining where cells
are destroyed, lining unprotected,
irritated by stomach acid
gastritis
swelling of stomach lining, caused
by irritating foods, alcohol, or
bacteria
acid
reflux
"back washing" of acid from the
stomach into the esophagus; also
called heartburn
© 2006 Plano ISD, Plano, TX
Chemical Digestion
 Mouth - chemical digestion begins in the
mouth with saliva (spit)
 Stomach - gastric juices (stomach acid,
mucus, enzymes) begin to break down the
food to smaller molecules
 Small intestine – food broken down even
more so your body can absorb the nutrients
** Most digestion occurs in the small
intestine – fats, proteins, and carbs.
 Large intestine – bacteria help with final
stage of digestion
© 2006 Plano ISD, Plano, TX
Nutrients
• Carbohydrates: starches and
sugars
• Proteins: simplest form is amino
acids
• Fats : absorbed as fatty acids
(with the help of bile from the
liver)
• Vitamins & Minerals
• Water
© 2006 Plano ISD, Plano, TX
Enzymes
 Enzymes are proteins that help
chemical digestion
 Enzymes help a chemical reaction
without being changed itself
 Found in raw fruits and
vegetables
 Also produced in the stomach,
small intestine and pancreas
© 2006 Plano ISD, Plano, TX
© 2006 Plano ISD, Plano, TX
1.
2.
3.
4.
© 2006 Plano ISD, Plano, TX
5.
6.
7.
8.
9.
10.
1. mouth
2. esophagus
3.
3. stomach
4. small intestine
5. large intestine
© 2006 Plano ISD, Plano, TX
6. anus
salivary glands
1.
liver
2.
3. bladder
gall
pancreas
4.
© 2006 Plano ISD, Plano, TX
1.
2.
3.
4.
5.
© 2006 Plano ISD, Plano, TX
6.
1.
2.
3.
4.
© 2006 Plano ISD, Plano, TX

Match the structure
with the number.




© 2006 Plano ISD, Plano, TX



salivary
small
large
gall
esophagus
pancreas
stomach
liver
anus
bladder
intestine
intestine
glands


Match the function
with the number.
contains
major enzymes
organ forfor
secretes
transports
stores
mixes
the 4 undigestible
and
accessory
enzymes
food
stores
by
for
 digestion
stores
bile
theproduces
first
andchemical
absorption
contains
villi
bile
starch
digestive
peristalsis
food
breakdown
organs
of nutrients
of food
 breakdown

© 2006 Plano ISD, Plano, TX


