topic 4

Question 1

peristalsis

Answer 1

rythmic, wavelike contractions in the walls of the alimentary canal

Question 2

salivary glands

Answer 2

secrete saliva (water, mucin, salivary amylase and lysozymes)

Question 3

mastication in mouth

Answer 3

breaks food into smaller pieces (increases sa ratio for enzyme efficiency)

Question 4

salivary amylase

Answer 4

starch to maltose

Question 5

lysozymes

Answer 5

digest bacteria

Question 5

pyloric sphincter

Answer 5

muscle at lower end of stomach that controls flow of food from stomach to small intestine

Question 6

stomach peristalsis

Answer 6

peristalsis churns and breaks up food and mixes it with gastric juice

Question 7

small intestine

Answer 7

ph: 8
intestinal juice
pancreatic juice
bile

Question 7

stomach juice

Answer 7

hydrochloric acid
- kills microorganisms
- acidic environment for enzymes
- stops salivary amylase (denaturing)
- convert pepsinogen to pepsin

pepsin: catalyse the digestion of proteins to peptones

Question 8

maltase

Answer 8

maltose to glucose

Question 9

lactase

Answer 9

lactose to glucose + galactose

Question 10

sucrase

Answer 10

sucrose to glucose + fructose

Question 11

peptidases

Answer 11

peptones to amino acids

Question 12

intestinal / pancreatic lipase

Answer 12

fats to fatty acids + glycerol

Question 13

pancreatic amylase

Answer 13

starch to maltose

Question 14

trypsin (a protease)

Answer 14

protein to peptones

Question 15

what neutralises stomach acid

Answer 15

sodium hydrogen carbonate

Question 16

large intestine

Answer 16

absorb water and mineral salts

Question 17

bile

Answer 17

bile salts: emulsify fats (break up fat globules into small droplets)
- Increase SA for efficient enzyme digestion by lipase

Question 18

sugars

Answer 18

small intestine to liver via hepatic portal vein

glucose oxidised during respiration
excess stored as glycogen in liver and skeletal muscle cells

Question 19

amino acids

Answer 19

small intestine to liver via hepatic portal vein

converted into new protoplasm (growth and repair of cells, form enzymes and hormones)

excess is deaminated

Question 20

deamination of amino acids

Answer 20

amino group removed from acid group through hydrolysis reaction

amino group converted into ammonia and then urea

urea transported to kidneys

remaining part is converted into glucose and glycogen

Question 20

fats

Answer 20

transported by lacteal to thoracic duct and then bloodstream

mostly not broken down, used to build protoplasm

during fasting, broken down to provide energy

Question 21

functions of liver

Answer 21

regulation of blood glucose concentration

production of bile

deamination of amino acids

iron storage

protein synthesis (from amino acids in diet)

breakdown of hormones

detoxification

Question 22

detoxification

Answer 22

alcohol dehydrogenase breaks down alcohol to acetaldehyde further broken down to compounds used in respiration

Question 23

effects of alcohol on digestive system

Answer 23

increased risk of gastric ulcers cirrhosis (liver cells destroyed, less able to function) haemorrhage, bleeding in liver lead to liver failure and death

Question 24

effects of alcohol on the nervous system

Answer 24

is a depressant (slows down brain functions) become carefree reduced self-control slurred speech blurred vision, poor muscular coordination slower reaction