Gastrointestinal system

Question 1

where does the GI system begin and end

Answer 1

begins in the mouth, continues through the thoratic cavity and ends in the anus

Question 2

what does the upper GI include

Answer 2

mouth, oesophagus, stomach and duodenum

Question 3

what does the lower GI system include

Answer 3

small intestine, large intestines, rectum and anus

Question 4

meaning of digestion

Answer 4

it is the chemical and mechanical breakdown of food

Question 5

what are the three phases of digestion

Answer 5

cephalic phase

gastric phase

intestinal phase

Question 6

what is the cephalic phase

Answer 6

starts with the external stimulus of food response from cerebral cortex, it leads to:

• increased saliva production and salivary amylase, lysozymes.

Question 7

what is the gastric phase

Answer 7

deglutition reflex (swallowing) moves food to the stomach in order for the phase to occur.

• the release of hydochloric acid and pepsin for mechanic digestion (churning)
• starts in the stomach, fills in the stomach which causes the stomach receptors recognising this and increases the production of gastric acid for the breakdown

Question 8

what is the intestinal phase

Answer 8

takes place in the small intestine.

• it feeds forward to promote digestion and absorption of nutrients

Question 9

what is ingestion

Answer 9

food being taken into the mouth

Question 10

what is secretion

Answer 10

the release, by cells within the GI tract of water, acid, buffers and enzymes

Question 11

what is chemical digestion

Answer 11

series of catabolic reactions that break large carbohydrates, lipids, and protein food molecules into smaller molecules which can be used by body cells

Question 12

which cells produce hydrochloric acid

Answer 12

parietal cells

Question 13

what does the villi do in the small intestine

Answer 13

increase the surface area in the small intestines which increases the surface area for absorption

Question 14

what are the three parts of the small intestine (in order)

Answer 14

1. Duodenum
2. Jejunum
3. Heum

Question 15

what happens in the large intestines during the food passage

Answer 15

excess water is absorbed, they also manufacture and absorb certain vitamins such as vitamin K which is needed for clotting

• a mixture of waste material, mucus and bacteria are then passed on to the rectum

Question 16

what happens in the mouth during the food passage

Answer 16

the teeth chew the food (mechanical digestion) also while swallowing saliva which contains an enzyme called amylase

Question 17

what is the scientific word for the food being broken down and being turned into a ball

Answer 17

bolus

Question 18

what happens in the stomach during the food passage

Answer 18

it is churned into a thick liquid called chyme. HCL is excreted by the parietal cells which lowers the pH levels in the stomach which increases the effectiveness of pepsin (an enzyme that is used to digest proteins)

Question 19

what happens in the small intestine during the food passage

Answer 19

bile is produced by the liver and is stored in the gallbladder which begins to breakdown of fat.

Question 20

what does lipase break down into

Answer 20

fat molecules to fatty acids and glycerol

Question 21

what does amylase break down into

Answer 21

maltose

Question 22

what does the rectum do during the food passage

Answer 22

stores the waste material prior to excretion