Chp 28 Digestion

Question 1

Digestion

Answer 1

Break down of large food molecules into smaller, soluble ones

Question 2

Mechanical digestion

Answer 2

Physical breakdown of food into smaller pieces

Question 3

Chemical digestion

Answer 3

Breakdown of food into smaller molecules by enzymes, stomach acid or bile

Question 4

Steps of human digestion

Answer 4

Ingestion
Digestion
Absorption
Egestion

Question 5

Mouth : Physical

Answer 5

Reduce food into smaller pieces increasing surface area for enzymes to work on
Food is turned into bolus

Question 6

Teeth formula

Answer 6

2I 1C 2PM 3M

Question 7

Incisor

Answer 7

Cutting + bitting

Question 8

Canine

Answer 8

Gripping + tearing

Question 9

Premolar + molars

Answer 9

Grinding + Crushing

Question 10

Mouth : Chemical

Answer 10

Salivary amylase
Consists of water, salt, mucin, amylase and lysozyme

Question 11

Oesophagus

Answer 11

Pushes food down into stomach

Question 12

Peristalsis

Answer 12

Rhythmic contraction and relaxation of muscles

Question 13

Stomach

Answer 13

Entrance : Cardiac sphincter muscle
Exit : Pyloric sphincter muscle
Muscular
Expandable
J-Shaped bag

Question 14

Gastric gland

Answer 14

Produces gastric hormones which causes production of gastric juice

Question 15

HCl in stomach

Answer 15

Converts pepsinogen into pepsin
Kills microorganism
Loosen fibrous food
Deactivates salivary amylase

Question 16

Pepsinogen

Answer 16

Activated becomes pepsin
Breaks down protein into peptides

Question 17

Mucus

Answer 17

Thick alkaline substance that protects the stomach from acid and enzymes

Question 18

Small intestine

Answer 18

absorption of nutrients through diffusion
covered in villus

Question 19

Deamination

Answer 19

Amino acids not used broken down in liver forming urea

Question 20

Lacteal

Answer 20

Absorbs fatty acid and glycerol into cells of villus lining

Question 21

Adaptation of villi

Answer 21

Large number
Large number of microvillus
Walls only one cell thick
Rich in blood supply

Question 22

Adaptation for small intestine

Answer 22

Very long
Numerous villi and microvilli
Thin walls
Lymph supply to carry fat away

Question 23

Duodenum

Answer 23

Secretes intestinal juice, bile and pancreatic juice

Question 24

Pancreatic juice

Answer 24

Produce in pancreas, enters duodenum via pancreatic duct
Contains water, sodium bicarbonate and enzymes
Sodium bicarbonate neutralises acid chyme

Question 25

Bile

Answer 25

Produced in liver, stored in gall bladder, enters duodenum via bile duct Consists of water, bile salt, bile pigments, cholesterol and phospholipids Bile salt emulsifies fat Excretes pigments biliverdin and bilirubin Excretes excess cholesterol

Question 26

Intestinal juice

Answer 26

Produced in duodenum Maltase, sucrase, peptidase

Question 27

Pancreas

Answer 27

Makes enzymes Starch -> amylase -> maltose Lipids -> lipase ->Fatty acid + glycerol Protein -> protease -> peptides

Question 28

Ileum

Answer 28

Absorption of digested food into circulatory system Blood capillaries->hepatic portal vein -> Liver

Question 29

Large intestine

Answer 29

Water reabsorption and elimination of faeces

Question 30

Caecum

Answer 30

Ends in appendix (Both useless)

Question 31

Colon

Answer 31

Reabsorbs water + mineral salts Prevents dehydration

Question 32

Rectum

Answer 32

Store semi-solid waste

Question 33

Anus

Answer 33

Waste passes out of body as faeces

Question 34

Liver

Answer 34

Storage of fat soluable vitamins, glycogen and minerals Detoxification of poisonous substance Produce heat Formation of cholesterol

Question 35

Hepatic artery

Answer 35

Brings oxygenated blood to liver

Question 36

Hepatic vein

Answer 36

Carries deoxygenated blood + other nutrients from liver

Question 37

Fibres in diet

Answer 37

Stimulates peristalsis - absorbs water providing bulk for intestine to push Prevents constipation - keeps faeces soft Prevents over-eating

Question 38

Balanced diet

Answer 38

Contain all essential nutrients in correct amount