The Digesgive System

Question 1

List all the parts of the human digestive system

Answer 1

• The mouth
• The oesophagus
• The stomach
• The liver
• The gallbladder
• The pancreas
• The small intestine
• The large intesting

Question 2

Function of the mouth:

Answer 2

The mouth is made up of two parts that help digest food. Firstly the teeth and tongue work together to chop and grind the food together. This also increases its surface area that the enzymes can come in contact. Secondly there arw the salivary glands. The salivary glands produce an enzyme called ‘amylase’ which catalyses the reaction that breaks down starch into simple sugars. Saliva also contains mucus which makes the food slippery and easier to swallow.

Question 3

Function of the oesophagus:

Answer 3

The oesophagus has muscles in its wall. These muscles contract behind the food to push it along towards the stomach.

Question 4

What is the wave like muscle contraction in the oesophagus called?

Answer 4

This type of wave-like muscle contraction is called ‘peristalsis’.

Question 5

Function of the stomach:

Answer 5

Food enters the stomach through a ring of muscle known as a sphincter. Contractions of the thick muscular walls of the stomach churn up the food into a liquid known as ‘chyme’.
Here the food is mixed with stomach acid so that the protein-digesting enzymes (proteases) have the correct pH to work efficiently. The stomach acid also kills bacteria that are ingested with the food.

Question 6

What are the rings of muscle in the entance and exit of the stomach called?

Answer 6

Sphincters

Question 7

What is the already churned up liquid of food in the stomach called?

Answer 7

Chyme

Question 8

Function of the liver

Answer 8

The liver produces a liquid called bile which is stored in the gall bladder. After a meal, bile travels along the bile duct and into the small intestine. The bile breaks up the fat in food into smaller
droplets which can then mix with watery liquids. This process is called ‘emulsification’.

Question 9

What is the process if bile breaking up globules of fat inti smaller molecules called?

Answer 9

Emulsification

Question 10

Function of the gall bladder:

Answer 10

Stores bile and bile leaves through a part in the gall bladder called the bile duct.

Question 11

Function of the small intestine:

Answer 11

The food is kept moving through the intestine by peristalsis. The small intestine is made up of the duodenum and ileum. Bile enters the duodenum after a meal and breaks up the fat into tiny droplets ready for lipases to break it down into simpler substances. Glands in the ileum produce more enzymes to break down the food. Now small molecules of digested food pass through the walls of the ileum and into the blood stream. Bile also reduces the pH of the acid comming in from the stomach to not burn the small intestine.

Question 12

Function of the large intestine:

Answer 12

The large intestine is made up of the colon, appendix and rectum. By the time food gets to the colon, digestible foods have been broken down and absorbed into the blood. Only indigestible material and water remains. The colon absorbs water into the blood and the undigested materialbecomes more solid. Semi-solid material (faeces) collects in the rectum before leaving the body via the anus.

Question 13

What is the function of bile?

Answer 13

Bile breaks down large globules of fat in the small instestine so they can then mix in with the other liquids. Bile also neutralizes the stomach acid comming into the small intestine so it doesnt burn it.

Question 14

Function of the pancreas:

Answer 14

This gland secretes hormones which control glucose levels in the blood. After eating, glucose levels tend to rise. This causes insulin to be released which causes excess glucose to be converted to glycogen for storage in the liver. When blood sugar drops, insulin secretion is replaced by glucagon which converts glycogen back into glucose.