Download Digestive System Types of Digestion Teeth/Saliva

Digestive SystemOver -
Digestive System
Disassemble the food you eat into smaller parts that can
be used to make energy (ATP) by your body and
provide nutrients.
Types of Digestion
Mechanical digestion physically breaks up and
crushes food. This occurs in both the mouth (teeth)
and stomach.
Chemical digestion breaks down food into molecules
using enzyme (special proteins) and acids.
Chemical digestion begins in the mouth and
continues into the stomach and small intestine.
The pathway for food
and drink as it enters
the digestive system
on it’s path through
the body.
Remember food
never really goes into
the body but rather
travels through it.
Teeth/Saliva
Teeth are the 1st step of
digestion. They help break
down the food to make it
smaller and easier to swallow.
Teeth are attached to strong
muscles and jaw bones to
help you break and grind your
food.
As you chew, your saliva gets
mixed in with the food and
makes it softer.
Saliva contains enzymes that
break down carbohydrates
The epiglottis
A flap of cartilage that closes over
the opening to the respiratory tract
as you swallow, keeping food out
–After food passes, epiglottis opens
again
–If you talk or laugh as you swallow,
food may enter the upper portion of
the respiratory tract
Esophagus
After you swallow, your food travels down the
esophagus, a long straight tube. The esophagus
squeezes the food with rhythmic muscles and
pushes the food along to the stomach.
No absorption takes place in
the esophagus.
Food and drink form a bolus
that moves by peristalsis down
towards the stomach.
–Your response is to choke & cough,
forcing food out of the respiratory
tract
Peristalsis
A series of involuntary
smooth muscle
contraction along the
walls of the digestive
tract
Stomach
•The lining of the stomach secretes mucus that
forms a protective layer between it and the acidic
environment of the stomach
•Food remains in stomach for about 2-4 hrs
•When food leaves it is the consistency of tomato
soup (YUMMY!).
Stomach
The stomach continues the digestion by squeezing
the food and adding acids that digest food. The
stomach churns the food until it turns into a milky
liquid called chyme. Then, the food passes to the
small intestine.
Small Intestines
A muscular tube about 6 m long
Called “small” because of how
narrow it is (only 2.5 cm in diameter)
- Digestion is COMPLETED here
- First 25 cm of the small intestine
called the duodenum
The small intestine then absorbs the
nutrients and minerals from the food.
Sending nutrients into the capillaries
that surrounds the small intestines.
Small Intestines
Liquid food stays in the intestine for 3-5
hrs. as it is moved through
•As food moves it passes over thousands
of tiny fingerlike structures called villus =
a single projection on the lining of small
intestine that function in the absorption of
food
•Now that food is in the form of small
molecules, it can be absorbed directly into
the cells of the villi (plural for villus)
•Food then diffuses into blood vessels of
the villus & enter the bloodstream
Pancreas
A soft, flattened gland that
secretes both digestive
enzymes & hormones into
the small intestine.
–The mixture of enzymes it
releases break down
carbohydrates, proteins, &
fats
Liver
Liver play a role in both the circulatory system as
well as the digestive system.
The liver processes the nutrients you eat so they
can be used by the rest of your body. It also stores
nutrients for later use.
Gall Bladder
Stores bile made by the
liver and secretes this
bile into the small
intestine.
Bile breaks up fats into
small droplets (much
like soap does) so that
they can be broken
down and absorbed
Large Intestines
- All indigestible material from a meal
then moves into the large intestine
= a muscular tube that is also called
the colon
- Large intestine is only about 1.5 m
long, but it is much wider that the
small intestine ( about 6.5cm in
diameter)
Large Intestines
•As indigestible mixture passes through the large
intestine, water and salts are absorbed by the
intestinal walls, leaving behind a more solid material
•This way water is NOT wasted
Bacteria in the large intestine make some B vitamins
and Vitamin K, which are absorbed as needed by the
body
These bacteria also stop harmful bacteria from
colonizing, reducing the risk of intestinal infections
End of Digestive
End EnESystem
Rectum: END of the digestive system where
feces is stored until eliminated out through
anus.
No picture need :)
Nutrients for the Body
Proteins in food are broken down into smaller pieces
then used to make more proteins with a specific
function.
Fat from food is broken down into fatty acids so it
can travel in the blood and be captured by hungry
cells. Then, the fatty acids that are not needed right
then are packaged away in bundles that are kept in
fat cells.
Your body breaks down the carbs into simple sugars
which are then absorbed into the bloodstream. Next,
the sugar level rises and your pancreas release
insulin.
Nutrients for the Body
Nutrients for the Body
Nutrients for the Body
Nutrients for the Body
Water to dissolve substances in blood, tissue fluids
and biochemical reactions
Fiber is plant material that the body cannot
digest that helps keep your food moving through
the digestive system and out.
Nutrients for the Body
Nutrients for the Body
Which systems does the
digestive system work with?
Circulatory
Muscular
Lymphatic
Ci
Circulatory System working with the Digestive System