Digestion

Question 1

What are the four stages of nutrition?

Answer 1

Ingestion, digestions, absorption, egestion

Question 2

What is ingestion?

Answer 2

Taking substances into the body through the mouth.

Question 3

What is digestion?

Answer 3

The breakdown of large insoluble molecules into smaller, water-soluble ones

Question 4

What is absorption?

Answer 4

The movement of digestive food through the wall of the intestine and into the blood or lymph.

Question 5

What is egestion?

Answer 5

The removal of undigested food (faeces) through the anus.

Question 6

What is the mouth’s role in digestion?

Answer 6

Here food enters the alimentary canal. It is converted to a bonus of food which is produced by teeth, tongue and saliva during mastication.

Question 7

What is the role of the salivary glands in digestion?

Answer 7

They produce saliva and pour onto the into the mouth. The saliva contains amylase which can start to breakdown starches.

Question 8

What is the role of the epiglottis in digestion?

Answer 8

It is a flap of muscle which closes the entry to the Trachea during swallowing.

Question 9

What is the role of the Oesophagus during digestion?

Answer 9

It is a muscular tube which helps food move down to the stomach by peristalsis.

Question 10

What is the liver’s role in digestion?

Answer 10

It produces bile, which helps to neutralise the acidic chyme and also emulsifies fats. Important in assimilation.

Question 11

What is the stomach’s role in digestion?

Answer 11

It is a muscular bag which stores food for a short time, and mixes food with acidic digestive juices to form the creamy liquid called Chyme.

Question 12

What is the duodenum’s role in digestions?

Answer 12

It is the first part of the small intestine, where semi-liquid food is mixed with pancreatic juice and bile.

Question 13

What is the pancreases role in digestion?

Answer 13

It produces pancreatic juice (contains enzymes, mucus and hydrogen carbonate which neutralises acidic chime) which is poured into the small intestine through the pancreatic duct.

Question 14

What is the illium’s role in digestion?

Answer 14

It is the longest part of the small intestine, where digestive food is absorbed into the blood and lymphatic system.

Question 15

What is the large intestine’s role in digestion?

Answer 15

The colon is part of the large intestine. It reabsorbs water from the blood contents: also absorbs some vitamins and mineralers

Question 16

Why are enzymes needed in digestion?

Answer 16

Because when ingested, carbohydrates, proteins and fats maybe too large to cross the gut wall and too insoluble to be transported in the watery blood plasma. Enzymes break down these food molecules by hydrolysis reactions

Question 17

What enzyme functions in the mouth?

Answer 17

Amylase is found in saliva and breaks down starch into maltose in the mouth

Question 18

What is the process called which can pass the food bolus down the gut.

Answer 18

Peristalsis

Question 19

What enzyme functions in the stomach?

Answer 19

Protease functions alongside hydrochloric acid to turn proteins into peptides.

Question 20

What enzymes are secreted by the pancreas, and what do they do?

Answer 20

It secretes: amylase to complete the conversion of starch to maltose, protease to complete the breakdown of peptides into amino acids, and lipase to convert fats into fatty acids and glycerol.

Question 21

What does the pancreas secrete to neutralise the acidic chyme from the stomach?

Answer 21

It secreted hydrogen carbonate which neutralises the acid so that amylase, protease, lipase can work In optimum (alkaline) pH levels.

Question 22

What is bile and what is its function?

Answer 22

Bile is made in the liver and stored in the gallbladder from where is it is released when needed. Bile emulsifies the flats (it converts them from large globules into smaller droplets giving them a greater surface area of the lipase to work on)

Question 23

What is water’s role in digestion?

Answer 23

The water is the solvent for the biochemical reactions of digestion and is also used in the hydrolysis reactions that split up the large insoluble food molecules