The digestive system

Question 1

What is the function of muscle cells?

Answer 1

Muscle cells can contract as they contain special protein fibres which can change their length

Question 2

Why do muscle cells contain lots of mitochondria?

Answer 2

They provide lots of energy which is needed for contraction

Question 3

How is muscle tissue adapted to its function?

Answer 3

It contains lots of protein fibres that allow it to contract and also it contains lots of mitochondria which provide the energy needed to contract

Question 4

What is the definition of a tissue?

Answer 4

A tissue is a group of cells with a similar structure and function

Question 5

What is the definition of an organ?

Answer 5

An organ is a group of tissues working together for a specific function, for example the stomach which contains muscle tissues and glandular tissue

Question 6

What do organs make up?

Answer 6

Organ systems

Question 7

Why can’t food molecules by absorbed into the bloodstream?

Answer 7

The molecules are too large and have to be digested

Question 8

What happens to food molecules during digestion?

Answer 8

They are broken down into smaller molecules by enzymes and can then be absorbed

Question 9

Describe the process of digestion (step by step)?

Answer 9

First food is chewed and passes through the mouth where enzymes in saliva begin to digest the starch into smaller sugar molecules
The food then passes down the oesophagus into the stomach where enzymes begin the digestion of proteins. The stomach also contains hydrochloric acid which helps the enzymes work by providing an ideal ph for them
The stomach muscles then churn the food into a fluid increasing the surface area for the enzymes to digest
The fluid then passes into the small intestine and chemicals are released into the small intestine from the pancreas and liver
The pancreas releases enzymes which continue the digestion of starch and protein. They also start the digestion of lipids
Bile is released from the liver and speeds up the digestion of lipids and neutralises stomach acid
The food continues down the small intestine where it releases enzymes to continue the digestion of protein and lipids
Also, in the small intestine small food molecules produced by digestion are absorbed into the bloodstream
The food then passes through the large intestine where water is absorbed into the body
Then faeces is released from the body

Question 10

What can the products pf digestion be used for in the body?

Answer 10

To make new carbohydrates, lipids and proteins