The mouth and
carbohydrate
digestion
Digestion in the mouth
Digestion begins inside
the oral cavity
• Mechanical
digestion- the teeth
grind food forming a
bolus
• Chemical digestionsalivary glands begin
carbohydrate
digestion
Salivary Glands produce
saliva which begins
carbohydrate digestion:
•There are three salivary
glands•Parotid (above the
mouth)
•Sublingual (below the
mouth- most superior)
•Sub-mandibular (below
the mouth- most inferior)
Sub mandibular
Saliva: is composed the following substances:
• Water- liquefies food
• Salts (electrolytes)
• Salivary amylase- enzyme that breaks down complex
carbohydrates
• Musin: protein that lubricates food
• IgA antibodies: protects against invaders
• Lysozyme: a bacteriostatic agent (keeps bacteria from
multiplying); fights tooth decay
• Growth factor
The saliva begins digestion of complex carbohydrates….
What are carbohydrates?
• Carbohydrates are
made of C, H and O
(carbon, hydrogen
and oxygen).
• Carbs make up 1-2 %
of each cell’s mass
What are carbohydrates?
They include:
• Polysaccharidescomplex sugars,
example- starch and
glycogen
• Disaccharides- double
sugar; example
fructose, galactose
• Monosaccharidessimple sugars (made
up of one sugar
molecule) exampleglucose
Saccharide = sugar
Carbohydrate digestion
The saliva in the mouth begins digestion
of Polysaccharides
• Two types of polysaccharides that are
ingested by the body are starch and
glycogen.
• Starch is the large molecule made by a
plant to store its glucose molecules. It
is found in starchy foods such as
potatoes & grains.
• Glycogen is the large, compact
molecules animals make in order to
store their glucose molecules, found
mainly in muscle and liver cells.
How saliva digests
polysaccharides
• Polysaccharides must
be broken down into
its glucose “building
blocks” to be absorbed
into our intestines and
then body cells.
• This is achieved by a
hydrolysis reaction.
• As each sugar is
broken off the chain,
an H2O must be added
into the reaction.
Hydro= water
Lysis= break
How saliva digests
polysaccharides
An enzyme (amylase) is
used to accomplish
hydrolysis.
• Speeds up the reaction
• Digests
polysaccharides in the
mouth, pharynx and
esophagus
• When carbs reach the
stomach they have
been broken into
disaccharides.
Click here for amylase reaction animation
Disaccharides
When polysaccharides
are digested they
become disaccharides:
• consist of 2
monosaccharides, or
a “double sugar”.
• Example: sucrose
(table sugar)
Di = two
Monosaccharides
• Di- and
polysaccharides can be
easily broken down to
the monosaccharide,
glucose; then it reacts
with oxygen in a series
of reactions called
cellular respiration to
form ATP which is the
direct energy source
for the cell.
Mono= one
After chemical and mechanical digestion is accomplished in
the mouth:
• It passes the wad of food (bolus) into the pharynx.
The pharynx has three regions(2 that move food)
• Oropharynx- back of the throat
• laryngopharnyx- behind the
larynx (voice box)
(the third is the nasopharynx which moves air when you breath
through your nose)
After passing through the pharynx, food moves into the
esophagus:
• Function: Moves food from pharynx to stomach:
1. Esophageal muscle relaxes to move food into the
pharynx
2. A wave of muscle contraction (parastalsis) moves food
into the esophagus
3. Mucous is released to reduce friction
This takes 4-8 seconds to move it to the stomach; amylase
is still active during this process
•If bolus gets stuck, stretch receptors cause more muscle
contractions
•Cardiac (gastroesophageal) sphincter opens to pass bolus
into the stomach.
Heartburn:
Hiatus hernia:
Hiccups:
The mouth and carbohydrate digestion
Digestion begins inside the oral cavity:
______________________________digestion- the teeth grind food forming a bolus
_______________________digestion- salivary glands begin carbohydrate digestion
• Salivary Glands produce ________________which begins
________________digestion:
•There are three salivary glands•___________________________________________(above the mouth)
•_______________________________(below the mouth- most superior)
•________________________________(below the mouth- most inferior)
Saliva: is composed the following substances:
• _________________________________liquefies food
• Salts (____________________________)
• _______________________enzyme that breaks down
complex carbohydrates
• Musin: protein that ______________________food
• ____________________: protects against invaders
• ____________: keeps bacteria from multiplying; fights tooth decay
• ___________________________________
carbohydrates
MAIN CHARACTERISTICS
Carbohydrates are made of C, H and O (__________________________________).
Three types are:
• _____________________________________complex sugars, example• _____________________________________ double sugar; example
• _____________________________________ simple sugars (made up of
one sugar molecule) example-
Carbohydrate digestion- digestion of Polysaccharides begins by breaking down:
_____________________________________
• made by• found in_____________________________________
• made by• found in-
carbohydrates
Carbohydrate digestionPolysaccharides must be broken down into its glucose “building blocks” in order to:
Chemical reaction that breaks down polysaccharides is called
__________________________________________________________________.
How it works:
• The enzyme used to accomplish hydrolysis: __________________________
How it works:
Where it works:
What it breaks polysaccharides into:
example:
Why is it important to digest carbs? What is the big picture here?
After chemical and mechanical digestion is accomplished in
the mouth:
• It passes the wad of food (______________) into the
_____________________________.
The pharynx has three regions(2 that move food)
• _________________________back of the throat
• ______________________behind the larynx (voice box)
(the third is the nasopharynx which moves air when you breath
through your nose)
After passing through the pharynx, food moves into the esophagus:
• Function:
1. Esophageal muscle relaxes to:
2. A wave of muscle contraction (______________) moves food into the esophagus
3. Mucous is released to
4. __________________________________________opens to pass bolus into the
stomach.