Diet 1 - Digestive System

Question 1

Phases of digestion

Answer 1

1. Ingestion
2. Movement
3. Mechanical and chemical digestion
4. Absorption
5. Elimination

Question 2

Types of digestion

Answer 2

• mechanical (physical)
  Mastication
• chemical
  Enzymatic reactions to improve digestion of
  > carbohydrates
  > proteins
  > lipids

Question 3

Alimentary tract

Answer 3

• mouth
• pharynx
• oesophagus
• stomach
• small intestine
• large intestine
• rectum
• anal canal
• accessory organs
  > saliva glands
  > pancreas
  > liver
  > biliary tract

Question 4

Digestive system organisation

Answer 4

• gastrointestinal tract (GI) tract
• direct link/path between organs
  structures:
• Mouth
• Pharynx
• Oesophagus
• Stomach
• Small intestine
• Large Intestine
• Rectum

Question 5

Mouth

Answer 5

• teeth mechanically break down food into small pieces
• tongue mixes food with saliva (contains amylase - helps break down starch)

Question 6

Pharynx

Answer 6

• epiglottis is a flap at back of throat
• it closes over preventing food from entering it

Question 7

Oesophagus

Answer 7

• approx. 10” long
• functions are:
  1. Secrete mucus
  2. Move food from throat to stomach using muscle movement called peristalsis
  (If acid from stomach gets in here = heartburn)

Question 8

Stomach

Answer 8

• J shaped muscular bag - stores food eaten and breaks it down into tiny pieces
• mixes food with digestive juices - contains enzymes to break down proteins and lipids
• acid in stomach kills bacteria
• food found here is called chyme

Question 9

Small intestine

Answer 9

• 7 meters long
• lining of walls has finger like projections called villi - increases surface area
• villi are covered in microvilli - further increases surface area for absorption
• 3 parts - Duodenum, Jejunum and lleum

Question 10

Small intestine (2)

Answer 10

• nutrients from food pass into bloodstream through small intestine walls

Absorbs:
– 80% ingested water
– Vitamins
– Minerals
– Carbohydrates
– Proteins
– Lipids

• secretes digestive enzymes

Question 11

Large intestine

Answer 11

• 5 feet long
• accepts what small intestines don’t absorb
  Rectum (short term storage - holds faeces before expelled)

Question 12

Large intestine (2)

Answer 12

Functions:
- bacterial digestion.
Ferment carbohydrates
- protein breakdown
- absorbs more water
- concentrate wastes

Question 13

What are your accessory organs

Answer 13

• liver
• gall bladder
• pancreas
  Not part of food path - but play critical role

Question 14

Liver

Answer 14

• directly affects digestion by producing bile
  Bile:
• helps digest fat
• filters out toxins and waste - including drugs and alcohol

Question 15

Gall bladder

Answer 15

• stores bile from liver - releases into small intestine
• fatty diets cause gallstones

Question 16

Pancreas

Answer 16

• produces digestive enzymes to digest fats, carbohydrates and proteins
• regulates blood sugar by producing insulin