Download File - King`s General Science

Main regions of the
alimentary canal and
associated organs
Mechanical
Digestion?
Chemical
Digestion?
Chemical Digestion
• Enzymes help to break the food into
smaller particles by speeding up
chemical reactions in living cells.
• Enzymes are not used up…they act as a
biological catalyst…
Protein example
Enzymes
Big Molecule of Protein
(for example)
Lots of Smaller Amino-acids
Enzymes used to break Proteins into smaller particles
Ingestion
• Is the taking in of food into the mouth and
swallowing it
• Teeth and jaws grind the food into smaller bits
• The saliva in the mouth contains
enzyme (Amylase) which helps
break up food chemically.
The oesophagus is the
tube which connects the
mouth to the stomach
Enzymes in the Alimentary Canal
The Rules of Engagement
•The Cracker Challenge states that one must
completely chew and swallow five (often six) dry
crackers in under 1 minute. Additionally, this
must be done without the aid of water or any
other beverage. The challenge is notorious for
seeming simple in theory but being exceedingly
difficult to actually accomplish. Many contenders
have fallen into the trap of underestimation.
Why Is The Challenge So Hard?
•In order to facilitate easy chewing and
swallowing, our mouths produce saliva. The
major hurdle standing between you and the
glory that comes with completing the Cracker
Challenge is that our mouths do not
produce saliva fast enough to easily
break down five dry crackers as quickly
as the challenge calls for. By the second or
third cracker, most people will find their
mouths bone-dry and be unable to properly
swallow the abundance of crumbs.
Digestion
• Is the breaking-up of food into small
soluble pieces.
• Food in the stomach is mixed up and stored
(turned into a soup-like liquid)
• Stomach cells make enzymes (Pepsin) and
hydrochloric acid are released to aid digestion
• This acid also kills bacteria present in food.
Stomach – bag with lots of muscle in its walls…
Food held ~ 1-4 hours, liquids ~ a few minutes
• Food is then slowly released into the small
intestine (gut) where most of the digestion
happens.
• First part – Duodenum
Where pancreas & bile fluids
added joins
Small intestine ~ 6 meters long
In the duodenum (enzymes ~ amylase, trypsin,
lipase) from the pancreas are added and bile
which is made in the liver is also added.
The bile helps to neutralize the acid from the
stomach and also helps to break the fat into
little droplets.
Gall bladder
stores bile
Enzymes in the Alimentary Canal
Enzymes in the Alimentary Canal
Enzymes in the Alimentary Canal