Digestive
System
Functions of the Digestive
System
1.
Ingestion = Food
enters the mouth.
Functions of the Digestive
System
1.
2.
Ingestion = Food enters the
mouth.
Digestion =
Process that breaks
food down into
small molecules
Functions of the Digestive
System
1.
2.
Ingestion = Food enters the
mouth.
Digestion = Process that
breaks food down into small
molecules
a) Mechanical digestion =
Food is chewed and
churned.
b) Chemical digestion =
Breaks down large food
molecules into smaller
molecules to be
absorbed by cells
Functions of the Digestive
System
1.
2.
3.
Ingestion = Food enters the
mouth.
Digestion = Process that
breaks food down into small
molecules
Absorption =
Small molecules of
food are taken into
the body cells.
Functions of the Digestive
System
1.
2.
3.
4.
Ingestion = Food enters the
mouth.
Digestion = Process that
breaks food down into small
molecules
Absorption = Small
molecules of food are taken
into the body cells.
Elimination =
Wastes made of
unabsorbed food
molecules pass out of the body.
Large Intestine
Which is not a function of
the digestive system?
a)
b)
c)
d)
Breaking down food into
molecules the body can
use
Absorbing food
molecules into the blood
to deliver to the body
Changing waste into
molecules the body can
use
Eliminating undigested
waste from the body
Organs of the Digestive
Tract
1.
Mouth = Digestion starts here.
Organs of the Digestive
Tract
1.
Mouth = Digestion starts here.
a) The tongue & teeth mechanically
break food up.
Organs of the Digestive
Tract
1.
Mouth = Digestion starts here.
a) The tongue & teeth mechanically
break food up.
b) Saliva chemically digests food.
a) Saliva = Mostly made of
water, also contains mucus
and enzymes
Organs of the Digestive
Tract
1.
Mouth = Digestion starts here.
a) The tongue & teeth mechanically
break food up.
b) Saliva chemically digests food.
a) Saliva = Mostly made of
water, also contains
mucus and ptyalin (an
enzyme)
c) When swallowing, the epiglottis
(a small flap of tissue) automatically
closes over the trachea (windpipe).
Organs of the Digestive
Tract
2.
Esophagus
a) Smooth muscles force food into the
mucus-lined esophagus.
b) Rhythmic muscular
contractions
(peristalsis) push food
downward.
Organs of the Digestive
Tract
3.
Stomach
a) Food undergoes mechanical digestion
when stomach muscles churn the food.
b) Chemical digestion
happens when hydrochloric
acid (HCl) and pepsin
break down the complex
proteins.
c) Peristalsis pushes the food
toward stomach’s exit.
Which is not an example
of mechanical digestion?
a)
b)
c)
d)
Teeth chewing food
Tongue breaking up
food
Smooth muscles in
stomach churning
food
Hydrochloric acid
breaking down
proteins
Organs of the Digestive
Tract
4. Small Intestine (6 meters long)
a) Most digestion happens here.
b) Intestinal juice
(full of enzymes)
breaks down food.
Organs of the Digestive
Tract
4. Small Intestine (6 meters long)
a)
b)
Most digestion happens here.
Intestinal juice (full of enzymes) breaks down food.
c) Digestive Helpers
•
Liver = Bile is
produced here (Bile
breaks up fats like
dish detergent
breaks up grease.).
Organs of the Digestive
Tract
4. Small Intestine (6 meters long)
a)
b)
Most digestion happens here.
Intestinal juice (full of enzymes) breaks down food.
c) Digestive Helpers
•
Liver = Bile is produced
here (Bile breaks up fats
like dish detergent breaks
up grease.).
•
Gall bladder = Bile
is stored here until
released into the small intestine.
Organs of the Digestive
Tract
4. Small Intestine (6 meters long)
a)
b)
Most digestion happens here.
Intestinal juice (full of enzymes) breaks down food.
c) Digestive Helpers
•
•
•
Liver = Bile is produced
here (Bile breaks up fats
like dish detergent breaks
up grease.).
Gall bladder = Bile is
stored here until released
into the small intestine.
Pancreas = Produces
pancreatic juices that
are released into the small intestine to break
down proteins, starches, and fats
Organs of the Digestive
Tract
4. Small Intestine (6 meters long)
a)
b)
Most digestion happens here.
Intestinal juice (full of
enzymes) breaks down food.
c) Digestive Helpers
• Liver
• Gall bladder
• Pancreas
d) Digested food is
absorbed through the villi in the
small intestine into a network of
blood vessels that carry the nutrients to
all parts of the body.
Organs of the Digestive
Tract
4. Small Intestine (6 meters long)
a)
b)
c)
Most digestion happens here.
Intestinal juice (full of enzymes)
breaks down food.
Digestive Helpers
•
d)
Liver, Gall bladder, Pancreas
Digested food is absorbed
through the villi into a network of
blood vessels that carry the
nutrients to all parts of the body.
e) By the time food leaves the small
intestine, it is empty of all nutrients
except water.
Where does most
digestion take place?
a)
b)
c)
d)
Mouth
Stomach
Small intestine
Liver
Organs of the Digestive
Tract
5. Large Intestine (1.5 meters long)
a) Undigested food spends 18–24 hours
here, and most of the water is absorbed.
Organs of the Digestive
Tract
4. Large Intestine (1.5 meters long)
a)
Undigested food spends 18–24 hours here, and most of
the water is absorbed.
b) Helpful bacteria
living in the large
intestine make
vitamins K and B.
Organs of the Digestive
Tract
4. Large Intestine (1.5 meters long)
a)
b)
Undigested food spends 18–24 hours here, and most of the
water is absorbed.
Helpful bacteria living in the
large intestine make vitamins
K and B.
c) Materials not
absorbed form into
solid waste (dead
bacteria, some fat and
protein, undigested
food, dried out parts of
digestive juices, and old intestinal cells).
Organs of the Digestive
Tract
4. Large Intestine (1.5 meters long)
a)
b)
c)
Undigested food spends 18–24 hours here, and most of the water is
absorbed.
Helpful bacteria living in the large
intestine make vitamins K and B.
Materials not absorbed form into
solid waste (dead bacteria,
some fat & protein, undigested
food, dried out parts of digestive
juices, and old intestinal cells).
d) Solid waste passes
into the rectum and is stored until it is
eliminated from the body through the anus.