Transcript What Happens to Food Once it Enters Your Mouth?

What Happens
to Food Once it
Enters Your
Mouth?
Digestion – the process that breaks down food into
small molecules that can be absorbed and moved into blood.
• Mechanical
Digestion: takes
place when food is
chewed, mixed, and
churned.
• Happens in the
mouth, esophagus,
and stomach.
• Chemical Digestion:
takes place when
chemical reactions
break down large
food molecules into
smaller ones.
• Happens in the
mouth, stomach,
small intestine.
Enzymes
• Proteins that speed
up reactions without
being used up.
• Enzymes are very
important to the
digestive process.
Organs of the Digestive System
• Digestive Tract – mouth, esophagus,
stomach, small intestine, large intestine,
rectum, anus. All food passes through
these organs.
• Accessory Organs – tongue, teeth,
salivary glands, liver, gall bladder, and
pancreas. Liver, gall bladder, and
pancreas make and store enzymes.
The Mouth – both mechanical and
chemical digestion happen here.
The Esophagus
• About 25 cm long.
• Takes about 4-10
seconds for food to
reach the stomach.
• Peristalsis moves
food down the
esophagus.
• No digestion occurs
here.
The Stomach
• Mechanical and
chemical digestion
happen here.
• Hydrochloric acid and
enzymes break down
food and kill bacteria.
• Food leaves in 2-4
hours as a thin,
watery liquid called
chyme.
The Small Intestine
• About 4-7 m in length.
• Many enzymes are
mixed with food here.
• Covered with villi to
increase surface
area.
• Food molecules are
absorbed here and
released into the
bloodstream.
Small Intestine and Villi
Large Intestine
• Main job is to absorb
water back into the
body from chyme.
• Peristalsis slows
down here meaning
food stays for up to 3
days.
• Semi-solid wastes are
released by the
rectum and anus.
Bacteria
• Are very important to the digestive
process.
• Feed on undigested material in large
intestine.
• Produce vitamins.
• Also produce gas.
Digestive System
• Chemical and physical digestion.
• Ingestion happens in the mouth;
digestion occurs in the mouth, stomach,
and small intestine; absorption occurs in
the small and large intestine.
• Accessory organs move and cut up food
and supply enzymes and other chemicals.
• Large intestine reabsorbs water.
One last look…