4. describe the structure, function, and interactions of the organs of the human digestive

Digestion is the process of breaking down food.

Digestion is how the body breaks down food to get the nutrients from it.

Digestion begins in the mouth,

teeth bite, at the front, Incisors

teeth chew, at the back teeth, Molars

teeth tear, the Canine teeth (the sharp pointy ones)

Having extra teeth, or hyperdontia, is nothing out of the ordinary. In fact, it’s estimated that up to 4% of people have more teeth than normal. These extra teeth are usually found in people’s mouths, funnily enough, which is why doctors were slightly surprised to discover a 22-year-old man sporting one in his nose. Yep, his nose.

We make Saliva in our mouth,

Saliva aids swallowing.

Saliva contains an ENZYME (salivary amylase) that converts starch to sugar.

investigate the action of amylase on starch; identify the substrate, product and enzyme


List of Tasks

  1. Make up a starch Solution
  2. Pour an equal amount it into two testubes
  3. Add some Salivary Amylase to the starch, by means of a straw or dropper
  4. Keep it at 37 oC by putting it in a water bath
  5. Test it.
    1. Add Iodine to the testtubes & observe
    2. or add benedicts solution and warm for a few minutes


When we tested the Starch and Salivary Amylase solution with Iodine we found the Starch was ___________

The one without Salivary Amylase went _________ because it had ________

When we tested the Starch and Salivary Amylase solution with Benedicts Solution it went ________ because it had _________

The one without Salivary Amylase stayed _________ because it had ________


The Enzyme Salivary Amylase changed the Substrate Starch into the Product Sugar


Make up a starch Solution

Add a small (1-2g) of starch to some warm water, making a paste, add cold water up to about 250ml (this will be too much)

Add some Salivary Amylase to the starch

There is chemical stock of this enzyme, but in order to see it really work, from the body, add a dolop of human saliva.

However, Saliva will contain germs (bacteria and viruses) from the donor. Therefore we should use a section of a drinking straw, to deliver the saliva into the test tube.

It is Essential that the Saliva Donor disposes of this straw without putting it down or allowing it to touch ANYTHING or ANYBODY before it gets sterilized in a Bleach Solution.

Keep it at 37oC

Hold the test tube in your hand for about 5-8 mins, body temperature is 37

Test it.

Add Iodine to the solution and see what happens ?

Add Iodine to a solution that had no Salivary Amylase added, what happens?

Add Iodine to a solution that was not kept at 37oC, what happens?

Add Bendicts solution to test for sugar instead of adding Iodine, see what happens!


When we added the Iodine, the one with Starch only went Dark Blue

The one with starch & Saliva did not go Blue ... it has no starch.


Salivary Amalayse converted the Starch into Sugar !

The Substrate, the Enzyme, the Product.

There are 3 sections here,

the 1st the substrate this is the raw material upon which can be changed to another material

the Enzyme is the biological chemical that allow the Substrate turn into the useful Product

The Product is the substance that the body wants and has to create enzymes to produce it!

the caterpillar, coccuun, butterfly.

substrate, enzyme, product

starch → saliva → sugar

The caterpillar is the organism that starts this change, but it does not change into a butterfly without first creating a coccuun.

The Coccuun is not living, but allows the caterpillar change into a butterfly.

The Butterfly is only come about by being metamorphazised from a caterpillar, but that needed a coccun to happen.

Write out the following and fill in the gaps as the word fits.

Enzymes are _______ found in living cells which act as biological _______ . Enzymes have a specific _______

which means they can only work on ____reaction each. Enzymes work best at a particular temperature called the _______ temperature. Above this temperature the enzymes are ________(or denatured). This is because their ________ is changed. Enzymes also work best at an optimum ______.

one shape pH proteins catalysts optimum destroyed function

Our bodies carry out many functions using enzymes. These biological chemicals help along natural reactions in much the same way as a catalyst does in chemistry (check out more on catalysts here)

identify and locate the major parts of the digestive system including the mouth, oesophagus, stomach, liver, pancreas, small intestine and large intestine, and know their functions





So what happens it then?

Another word for throat is Oesphagus!

Once swallowed the food passes down the oesophagus. The oesophagus has muscle tissue in its wall. A ring of muscular contraction moves slowly downwards, passing the food in front of it. This is called peristalsis.

Really fantastic digestion animation right here

Where does it go from here ?

Sketch the Diagram,

Fill out the functions of the various organs of the digestive system