Transcript Digestive System

Digestive System
Function
• Break down food into particles
the body can use
• Particles are absorbed into
blood and carried throughout
body
• Wastes are removed from the
body
Organs Involved
1. Mouth
2. Esophagus
3. Stomach
4. Pancreas
5. Liver
6. Gallbladder
7. Small Intestine
8. Large Intestine
9. Rectum
• Digestion-process where body breaks
down food
• 2 Kinds:
1) Mechanical-physically broken down
2) Chemical-chemicals break food
down
–Enzymes-proteins that speed up
chemical reactions in the body
»Pepsin-breaks down protein
»Amylase-breaks down starch
• Absorption-nutrients pass
though wall of digestive
system into blood. The
circulatory system will then
carry the nutrients to the cells
of the body.
• Saliva-fluid released by mouth;
contains enzymes
The Mouth
• Mechanical digestion starts with
teeth
• Saliva mixes with food moistening
• Chemical digestion also starts
breaking down starch into sugar
• Salivary Glands-produce Saliva
Esophagus
• Muscular tube that connects mouth
to stomach, lined with mucus
• 2 openings at back of mouth-one to
trachea, one for esophagus
• Epiglottis-flap covering trachea
• Peristalsis-involuntary waves of
muscle contractions to push food
along
Stomach
• J-shaped Pouch
• Mechanical digestion occurs here
when strong muscles squeeze
food. MOST mechanical digestion
occurs here.
• Chemical digestion occurs at
same time-acids and other
chemicals break down food
Stomach cont…
• Contains hydrochloric acid-a very strong
acid which would burn through clothing but
without this acid, your stomach would not
work properly.
• Has a mucus lining-coats and protects
your stomach
• Your stomach
produces a new
lining every 2 days.
Stomach cont…
• Heartburn is when some of the
stomach acid starts to move back
up the esophagus causing a
burning sensation in chest.
• Stomach ulcer-when a person
produces too much stomach acid
and it burns a hole in the stomach
lining.
Small Intestine
• Most chemical digestion occurs and
absorption of nutrients takes place
• Covered with villi-tiny finger shaped
structures with capillaries inside
• Capillaries inside villi pick up
nutrients so blood can carry to rest
of body
Cross Section of
Small Intestine
Liver, Gallbladder and Pancreas
(Food does not pass through these organs)
• Liver-largest and heaviest internal
organ inside the body
–Produces bile-substance that
breaks down fat
• Gallbladder-stores bile
• Pancreas-produces chemicals that
break down starches, proteins and
fats
Large Intestine
• Removes water from undigested
material
• Contains helpful bacteria that
produce vitamins
Large Intestine Cont…
Rectum
• Waste is compressed into a solid
form
• “Holding tank” for wastes until
they can be removed
• Removed from the body through
the anus-a muscular opening at
the end of the rectum