ABSORPTION of NUTRIENTS
Digestive System
Warm-up
• What happens to food after you eat it?
• Name the biomolecules (carbohydrates,
proteins, lipids) you think are in this food.
Engage
• Time to Chew!
Explore
• Digestion Animation – What happens at
each step in Digestion?
Digestion Notes
• The function of the digestive system is to
convert food into smaller molecules that can be
used by cells.
• Digestion begins in the MOUTH
– Teeth tear food apart
– The Enzyme AMYLASE begins to break down
carbohydrates (starch).
Enzymes are proteins
• Each enzyme is the specific helper to
a specific reaction
– each enzyme needs to be the right shape for
the job
– enzymes are named for the reaction
they help
Oh, I get it!
They end
in -ase
•
•
•
•
sucrase breaks down sucrose
proteases breakdown proteins
lipases breakdown lipids
DNA polymerase builds DNA
s6
Enzymes aren’t used up
• Enzymes are not changed by the reaction
– used only temporarily
– re-used again for the same reaction with other
molecules
– Enzymes work by speeding up the rate of a
reaction (lowering the activation energy)
substrate
active site
product
enzyme
It’s shape that matters!
• Lock & Key model
– shape of protein
allows enzyme &
substrate to fit
– specific enzyme for
each specific
reaction
• The food (bolus) passes down your
ESOPHAGUS by peristalsis to your
STOMACH.
– In the stomach, HYDROCHLORIC ACID
helps to break down food.
– The enzyme PEPSIN starts to break down
proteins.
• The mixture leaving your stomach is
called CHYME.
• The chyme moves into the SMALL
INTESTINE.
– Most of the chemical digestion and
absorption of nutrients occurs here.
• Amylase breaks down starch
• Trypsin breaks down protein
• Lipase breaks down fat
– Your PANCREAS produces these enzymes.
Small Intestine
• Your liver releases BILE into the small
intestine which helps in fat digestion.
Small Intestine - Villi
• VILLI in your small intestine are fingerlike
projections made of connective tissue that
absorb nutrients into your bloodstream.
Large Intestine
• The chyme now moves to the LARGE
INTESTINE, where water is removed.
• Microorganisms
(probiotics)
help maintain
the health of the
large intestine by
reducing the growth
of harmful bacteria
Removal
• After water has been removed, the waste
moves through the rectum and out of the
body through the anus.
• Large Intestine is an organ that functions
in both digestive and excretory system
Excretory System
• Animals produce waste products that
must be removed from their body.
• Most animals have a system that deals
with nitrogen-rich wastes from the
breakdown of proteins and nucleic
acids.
• Ammonia (NH3) is toxic.
• In addition, it helps maintain
homeostasis – balancing osmotic action
and pH.
Urinary System
Circulatory System
• Humans and other vertebrates have a closed
circulatory system
Heart
• Composed of muscle
• The right and left sides of the heart are
separated by a septum (prevents the mixing
of oxygen rich and oxygen poor blood)
Blood Vessels
• 3 types
– Artery: carry oxygen rich blood from heart to
tissue. Thick walled due to pressure..
– Capillary: smallest blood vessels (one cell
thick. Important for bringing nutrients and
oxygen to tissues and absorbing CO2 and
other waste products.
– Vein: returns oxygen
poor blood to heart.
Contains valves for
one way flow.
Organs
• Esophagus- food tube connecting mouth
to the stomach.
• Stomach- continues digestion of food.
Hydrochloric Acid helps in this process.
• Small Intestine- Most of the absorption of
nutrients happen here.
• Large Intestine- Leads waste to the
rectum. Water is absorbed here.
• Rectum- Holding area for feces.
• Anus- opening where wastes leave the
body.
• Liver- cleans the blood by filtering poisons
and wastes.
• Gallbladder- aids the breakdown of fats.
• Pancreas- located behind the stomach.
Produce hormones (insulin) that regulate
blood sugar levels. Produces enzymes that
help with digestion.
Elaborate/Evaluate-Draw and
Describe
• Name the biomolecules
contained in this
cheeseburger.
• Describe how the
cheeseburger is
digested from the
mouth to the large
intestine. Include
enzymes that break
down each biomolecule
in the different organs.