Digestion and Absorption.

Question 1

What is digestion and why is it important?

Answer 1

When food has been eaten it must be broken down in the body by the process of digestion so that the nutrients can be absorbed into the bloodstream.

Question 2

Where does the process of digestion take place?

Answer 2

The whole process takes place in the digestive system which begins at the mouth and ends at the anus.

Question 3

Food must be small enough to swallow and is physically broken down by two means. What are they?

Answer 3

Food must be small enough to swallow, and is first broken up in the mouth by the action of the teeth and jaws. The muscular action of the stomach also reduces the size of the food particles.

Question 4

What three ways are food digested by the mouth?

Answer 4

• Teeth.
• Tongue.
• Salivary glands.

Question 5

What do the teeth do for physical digestion?

Answer 5

Tear, rip and grind the food into pieces small enough to swallow.

Question 6

What does the tongue do for physical digestion?

Answer 6

Pushes the food round the mouth and down the throat.

Question 7

What do the salivary glands do for physical digestion?

Answer 7

Produce saliva to moisten food and make it easy to swallow.

Question 8

How does food enter the stomach?

Answer 8

Food enters the stomach via the sphincter muscle at the top.

Question 9

What do strong muscular waves in the stomach do?

Answer 9

Strong muscular waves move the food around and help to break it down and mix it with gastric juices and mucus produced in the stomach.

Question 10

What is the broken down food in the stomach referred to?

Answer 10

The broken down food is referred to as chyme.

Question 11

Fill in the missing spaces:
During digestion, a ____ of ______ or digestive _____ are produced. These contain ______ that speed ____ chemical ______.

Answer 11

During digestion, a variety of chemicals or digestive juices are produced. These contain enzymes which speed up chemical reactions.

Question 12

What three places do proteins break down?

Answer 12

• Stomach.
• Duodenum.
• Ileum.

Question 13

How does the digestion of proteins happen in the stomach?

Answer 13

Pepsin breakdown proteins into small chains of amino acids called peptides.

Renin clots milk so that the pepsin can act on it more efficiently.

Question 14

How does the digestion of proteins happen in the duodenum?

Answer 14

Trypsin breakdown proteins into peptones.

Question 15

How does the digestion of proteins happen in the ileum?

Answer 15

Erepsin converts peptones to amino acids to complete protein digestion.

Question 16

How does the absorption of amino acids by the villi take place?

Answer 16

Amino acids are absorbed in the villi, into the blood capillaries then into the circulatory system.

Question 17

What two places do fats break down?

Answer 17

• Duodenum.
• Ileum.

Question 18

How does the digestion of fats happen in the duodenum?

Answer 18

Bile emulsifies fats to disperse them in small droplets.
Lipase changes fat to fatty acid and glycerol.

Question 19

How does the digestion of fats happen in the ileum?

Answer 19

Lipase continues to break down fat into fatty acid and glycerol.

Question 20

How does absorption of fats in the small intestine take place?

Answer 20

In the small intestine the villi contain lacteal which absorbs the fatty acids and glycerol and is then recombined to form fats. They then pass into the lymphatic system, then into the bloodstream.

Question 21

What three places do carbohydrates break down?

Answer 21

• Mouth.
• Duodenum.
• Ileum.

Question 22

How does the absorption of carbohydrates take place?

Answer 22

Glucose is absorbed by the blood capillaries in the villi.

Question 23

How does the digestion of carbohydrates happen in the ileum?

Answer 23

Maltase beaks down maltose to glucose.
Invertase breaks down sucrose into glucose and fructose.
Lactase breaks down lactose into glucose and galactose.

Question 24

How does the digestion of carbohydrates happen in the duodenum?

Answer 24

Pancreatic amylase breaks down undigested starch to maltose.