Nutrition In Humans

Question 1

What contributes to differentiating energy requirement

Answer 1

Activity levels
Age
Pregnancy
Lifestyle
Climate
Metabolic rate
Health/medical conditions

Question 2

From the mouth the food passes through the pharynx (back of throat) and then where?

Answer 2

Dow on the oesophagus

Question 3

What is peristalsis?

Answer 3

Waves of muscular contraction followed by relaxation that pushes food down the oesophagus and down into the stomach. It occurs along the entire length of the digestive system

Question 4

How is the oesophagus adapted to suit its function as a passage way?

Answer 4

Muscular

Mucus is produced from goblet cells to reduce friction

Question 5

Describe three main events that take place in the stomach

Answer 5

HCL is produced. This gives the correct ph for the enzyme pepsin to work. Acid also kills any ingested bacteria
Mechanical digestion by peristaltic movements
Chemical digestion. Pepsin realised from stomach lining and breaks large protein molecules down to amino acids

Question 6

Where is bile produced and stored

Answer 6

Produced by liver, stored by gall bladder

Question 7

Why do we need bile

Answer 7

Neutralises stomach acid and emulsifies lipids

Question 8

From the stomach the food enters a region of the small intestine called the

Answer 8

Duodenum

Question 9

What is the alimentary canal?

Answer 9

The whole digestive system.

Question 10

What happens in the duodenum

Answer 10

Pancreatic juices from the pancreas neutralises stomach acid and more enzymes are added.

Question 11

What is the other part of the small intestine called?

Answer 11

The ileum

Question 12

What happens in the ileum

Answer 12

Small molecules (final products of digestion) e.g glucose, amino acids, fatty acids and glycerol, vitamins and minerals are absorbed.

Question 13

How is the ileum adapted to its absorption role?

Answer 13

The whole surface is folded and covered with villi

Question 14

What passes into the large intestine?

Answer 14

Digestion is finished by this point and the waste material consists of fibre and water and some dead or living bacteria

Question 15

What is the first part of the large intestine called?

Answer 15

Colon

Question 16

What does the colon do?

Answer 16

Reabsorbs most of the water from the contents leaving faeces

Question 17

What happens if the water is not absorbed?

Answer 17

Too much water is lost (dehydration)

The faeces is too liquid (diarrhoea)

Question 18

Why is there so much water to be absorbed?

Answer 18

Lots of water has been added from the bile, pancreatic juices, saliva, music, gastric juices.

Question 19

How does the structure of the large intestine compare to the small intestine?

Answer 19

Large also has some internal folds but no villi
Also muscular to move material by peristalsis
Wider diameters that the ileum but much shorter in length

Question 20

What is the final region of the large intestine called?

Answer 20

The rectum where the faeces is stored temporarily

Question 21

How does villi help absorption in the small intestine?

Answer 21

Big surface area
Contain blood capillaries to carry away absorbed nutrients
The villi have a rich blood supply. The blood supply has a lower concentration of food molecules and so diffusion occurs quickly.