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Primary 4 · Science · Systems: Digestive

Systems: Digestive questions for Primary 4 Science

10 questions to work through online, 2 of them written out the way the paper asks. Answer and you get the working straight away, then a score at the end. No sign-up, and you can retake it as often as you like.

  • Why the small intestine is long
  • What happens in the stomach
  • Where digestion begins
  • Following the food
  • Reading a lettered diagram
  • Chewing and surface
  • What the teeth and saliva do
  • Naming a part
  • Naming what carries food away
  • Reasoning about the system
0 of 10 answered
Question 1 of 10Why the small intestine is long
The digestive systemmouthWgulletXstomachYsmall intestineZlarge intestine
The parts in the order food passes through them.
The part labelled Z in the diagram above is several metres long and folded. Why?
Question 2 of 10What happens in the stomach

Same picture as the question above.

Which two of these happen at the part labelled Y in the diagram above?
A
Food is churned and mixed.
B
Digestive juices are added to the food.
C
Digested food passes into the blood.
D
Water is taken out of what is left.
Question 3 of 10Where digestion begins

Same picture as the question above.

According to the diagram, at which part does digestion begin?
Question 4 of 10Following the food
A boy swallows a mouthful of rice. Which order do the parts act on it in?
Question 5 of 10Reading a lettered diagram
The digestive systemmouthWgulletXstomachYsmall intestineZlarge intestine
The parts in the order food passes through them.
In the diagram above, where would you expect to find the most digested food?
Question 6 of 10Chewing and surface
Table of Number of pieces, Time to break down (min) for left whole, cut in half, cut into eight
Piece of breadNumber of piecesTime to break down (min)
left whole126
cut in half219
cut into eight89
Identical amounts of bread were put into the same digestive liquid.
Based on the table above, why does chewing food help digestion?
Question 7 of 10What the teeth and saliva do
Which two of these describe what happens in the mouth?
A
The teeth cut and grind the food into smaller pieces.
B
Saliva makes the food easier to swallow.
C
The food is squeezed along by the muscles of the gullet.
D
Undigested food is stored before leaving the body.
Question 8 of 10Naming a part
The digestive systemmouthWgulletXstomachYsmall intestineZlarge intestine
The parts in the order food passes through them.
Look at the part labelled Z in the diagram above, where digested food passes into the blood.What is the name of this part?
Question 9 of 10Naming what carries food away
Once food has been digested and passes through the wall of the small intestine, something carries it to every part of the body.What carries it?
Question 10 of 10Reasoning about the system
Why can a person who has had part of their small intestine removed become weak even though they eat normally?
Answers and explanations for all 10 questions

Every answer with the reasoning behind it. Worth reading after you have tried the set — or on its own, if you are a parent marking it.

  1. The part labelled Z in the diagram above is several metres long and folded. Why?

    Answer: so there is a large surface for digested food to pass into the blood

    Digested food passes through the wall of the small intestine into the blood. Length and folds give a huge surface for that to happen across, so very little is wasted.

  2. Which two of these happen at the part labelled Y in the diagram above?

    Answer: A and B only

    Y is the stomach. It churns the food and adds digestive juices to it. Absorbing into the blood and removing water both happen further along.

  3. According to the diagram, at which part does digestion begin?

    Answer: W

    Digestion begins at W, the mouth: the teeth break the food up and saliva starts to break it down chemically.

  4. A boy swallows a mouthful of rice. Which order do the parts act on it in?

    Answer: mouth, gullet, stomach, small intestine, large intestine

    Food goes in at the mouth, down the gullet to the stomach, on to the small intestine where it is absorbed, and finally to the large intestine.

  5. In the diagram above, where would you expect to find the most digested food?

    Answer: Z

    Digestion is completed in the small intestine, so food at Z is more fully digested than anywhere before it.

  6. Based on the table above, why does chewing food help digestion?

    Answer: Smaller pieces have more surface for the digestive juices to act on.

    Cutting the same bread into more pieces cut the time from 26 to 9 minutes. More pieces means more surface exposed, so the juices work faster — which is exactly what chewing does.

  7. Which two of these describe what happens in the mouth?

    Answer: A and B only

    In the mouth the teeth break the food up and saliva moistens it, which is what makes a dry mouthful possible to swallow.

  8. Look at the part labelled Z in the diagram above, where digested food passes into the blood. What is the name of this part?

    Answer: small intestine

    Z is the small intestine, where digested food passes into the blood.

  9. Once food has been digested and passes through the wall of the small intestine, something carries it to every part of the body. What carries it?

    Answer: blood

    Digested food is carried around the body by the blood.

  10. Why can a person who has had part of their small intestine removed become weak even though they eat normally?

    Answer: There is less surface for digested food to pass into the blood, so less of the food is used.

    The small intestine is where digested food is absorbed. With less of it, less food gets into the blood, so a normal meal delivers less to the body.