The Digestive System

Question 1

How much food do humans eat (on average) per day?

Answer 1

Humans eat between 1 - 2.7kg of food per day

Question 2

How much food do humans eat (on average) over a lifetime?

Answer 2

Humans eat more than 28,800kg of food over a lifetime.

Question 3

How many organs are in the digestive system?

Answer 3

10 organs.

Question 4

How many specialised cells are in the digestive system?

Answer 4

Over 20 specialised cells.

Question 5

How long does the digestive system last?

Answer 5

30 - 40 hours.

Question 6

What does the gastrointestinal tract do?

Answer 6

It transports food.

Question 7

What is the internal surface area of the gastrointestinal tract?

Answer 7

30 - 40 meters.

Question 8

What is the purpose of the pancreas, gallbladder and liver?

Answer 8

They break down food.

Question 9

What do enzymes, hormones, nerves and blood do?

Answer 9

Break down food, modulate digestive process and deliver the final products.

Question 10

What is the mesentery?

Answer 10

A large stretch of tissue.

Question 11

What is the mesentery’s purpose?

Answer 11

It supports and positions organs.

Question 12

What is the function of the teeth in the digestive process?

Answer 12

They mechanically break down food.

Question 13

What is the function of saliva in the digestive system?

Answer 13

Saliva carries enzymes.

Question 14

What do the enzymes in saliva break down?

Answer 14

Starch.

Question 15

Do enzymes complete chemical or mechanical digestion?

Answer 15

Chemical.

Question 16

What are the functions of stomach acid?

Answer 16

It kills bacteria, and lowers the Ph for enzymes to survive.

Question 17

Why are the walls of the stomach muscular?

Answer 17

To churn up food.

Question 18

What happens in the small intestine?

Answer 18

Small, soluble molecules are absorbed into the bloodstream.

Question 19

What happens in the large intestine?

Answer 19

Water is reabsorbed.

Question 20

What is the liver’s function?

Answer 20

It produces bile to digest lipids.

Question 21

What is the function of the pancreas?

Answer 21

It produces several enzymes.

Question 22

What are enzymes?

Answer 22

Catalysts.

Question 23

What do enzymes do?

Answer 23

They speed up chemical reactions.

Question 24

True or false: enzymes can bind to many types of substrates.

Answer 24

False

Question 25

True or false: enzymes are not altered by the reactions they speed up.

Answer 25

True

Question 26

What does pepsin break down?

Answer 26

Proteins.

Question 27

What are proteins broken down into (by pepsin)?

Answer 27

Amino acids.

Question 28

What are lipids broken down by?

Answer 28

Lipase

Question 29

What does lipase break down lipids into?

Answer 29

Fatty acids

Question 30

What does amylase break down?

Answer 30

Carbohydrates

Question 31

What are carbohydrates broken down into (by amylase)?

Answer 31

Small sugars

Question 32

What is the purpose of villi?

Answer 32

To absorb soluble substances to be passed into the bloodstream.

Question 33

What is the process of soluble substances being passed into the bloodstream called?

Answer 33

Diffusion

Question 34

Name 3 adaptations of villi:

Answer 34

Thin walls, large surface area, good blood supply.

Question 35

Why do villi have thin walls?

Answer 35

So that substances don't have to travel far to get to blood.

Question 36

Why do villi have a large surface area?

Answer 36

To make absorption faster - more molecules can be absorbed at one time.

Question 37

Why do villi have good blood supply?

Answer 37

So that substances can be immediately transported to body cells.

Question 38

What is the first step of the digestive process?

Answer 38

The brain anticipates food, and sends an electrical impulse to make the salivary glands start to produce saliva.

Question 39

What happens after the salivary glands start to produce saliva?

Answer 39

Chewing combines saliva and food.

Question 40

What does chewing the saliva and food create?

Answer 40

A bolus.

Question 41

What is the name of the tube which the bolus is passed down?

Answer 41

The oesophagus.

Question 42

What is the name of the muscle contractions that moves food down the oesophagus?

Answer 42

Peristalsis.

Question 43

After the bolus is in the stomach, what happens next?

Answer 43

The stomach walls break it into chunks.

Question 44

What do the cells in the lining of the stomach secrete?

Answer 44

Hormones.

Question 45

What do the hormones (which the cells in the lining of the stomach secrete) trigger?

Answer 45

Acid and enzyme-rich juices are released from the stomach wall. They also alert the pancreas, liver and gallbladder to produce digestive juices and transfer bile.

Question 46

How long does it take for the bolus to become chyme?

Answer 46

3 hours

Question 47

What does the bolus become?

Answer 47

Chyme

Question 48

After the bolus becomes chyme, where does it go?

Answer 48

The small intestine

Question 49

The liver sends bile to the gallbladder, where is this secreted?

Answer 49

The first portion of the small intestine - the duodenum.

Question 50

What does bile dissolve (in chyme)?

Answer 50

fat.

Question 51

What is fat in chyme broken down into?

Answer 51

fatty acids and glycerol.

Question 52

What are the names of the lower regions of the small intestine?

Answer 52

The jejunum and ileum.

Question 53

What is another name for the large intestine?

Answer 53

The colon.

Question 54

What happens in the colon?

Answer 54

leftover fibre, water and dead cells are reabsorbed.

Question 55

Where does stool go after being in the large intestine?

Answer 55

the rectum.

Question 56

Where is stool egested from?

Answer 56

the anus.

Question 57

What is egestion?

Answer 57

The expulsion of undigested food via the anus.

Question 58

What do gut bacteria live off, in a diet?

Answer 58

Fibre

Question 59

What do gut bacteria do?

Answer 59

Assist in breaking down food molecules, produce some vitamins, break down harmful toxins.

Question 60

Give some examples of vitamins that gut bacteria produce.

Answer 60

Vitamin K and B12

Question 61

What can increase gut bacteria?

Answer 61

Probiotics