Human Biology (b)

Question 1

nutrition defn.

Answer 1

how an animal gets its food

Question 2

different types of animals (how. they get food)

Answer 2

herbivores- feed mainly on plants
carnivores- feed mainly on other animals
omnivores- feed on both plants and animals

Question 3

autotroph defn.

Answer 3

organism that produces complex organic compounds from simple substances present in its surroundings (generally using energy from photosynthesis or chemosynthesis)

Question 4

heterotroph defn.

Answer 4

cannot manufacture its own food and must take it in from the environment

Question 5

stages in human nutrition

Answer 5

ingestion- consumption through the mouth into GI tract (gastro intestinal or alimentary canal)
digestion- physical (chewing/churning) and chemical (enzymes) breakdown of food
absorption- passing of useful components of food from GI tract into the blood
Egestion- removal of unabsorbed wastes from the GI tract

Question 6

what is the digestive system

Answer 6

long tube starting at the south and ending at the anus (associated glands, salivary glands, liver, pancreas, attached

Question 7

enzymes, where they’re found and their pH

Answer 7

Salivary amylase- mouth- 7
protease- stomach- 1
intestinal amylase- duodenum (small intestine)- 8/9
lipase- duodenum (small intestine)- 8/9

Question 8

human dental formula

Answer 8

(i2, c1, pm2, m3) x2= 32

Question 9

what each tooth does

Answer 9

incisors cut food
canines grip food
premolars and molars cut and grind food

Question 10

how the mouth takes part in digestion

Answer 10

mouth chews (physical) 
saliva contains water, salts and amylase(inhibited by acid in stomach) which breaks starch down into maltose (pH 7)

Question 11

what chewing etc does

Answer 11

food formed into bolus and is pushed into pharynx, epiglottis closes over the trachea and food passes down the oesophagus by peristalsis

Question 12

what is peristalsis

Answer 12

muscular action in the walls of the alimentary canal that moves content along, fibre stimulates peristalsis by absorbing water and expanding, the physical bulk stimulates the intestine

Question 13

what is the oesophagus

Answer 13

muscular tube that moves food by peristalsis, has no direct digestive role but can aid mechanical digestion

Question 14

glands for digestion

Answer 14

liver, gall blader, pancreas, salivary gland

Question 15

about the stomach

Answer 15

muscular bag that holds and digests food, lining is heavily folded forming millions of gastric glands which produce gastric juice (mucus, pepsinogen and hydrochloric acid)

Question 16

what does mucus do in the stomach

Answer 16

coats the stomach and prevents self-digestion

Question 17

about pepsinogen

Answer 17

inactive enzyme (so it doesn’t digest the cells producing it), converted to protease pepsin by the acid in the stomach

Question 18

what does the acid in the stomach do

Answer 18

1. kills bacteria
2. loosens fibrous and cellular foods
3. activates pepsinogen
4. denatures salivary amylase

Question 19

what does the stomach turn food into

Answer 19

chyme

Question 20

pancreas role

Answer 20

secretes insulin and pancreatic juice

Question 21

what does pancreatic juice do

Answer 21

contains sodium hydrogen carbonate that neutralises chyme and contains enzymes (ie. amylase and lipase)

Question 22

what does the liver do

Answer 22

1. breaks down red blood cells
2. makes bile
3. detoxifies the blood
4. forms urea out of excess amino acids and uric acid from excess nucleic acids
5. converts glucose to glycogen for storage
6. converts carbohydrates to fat
7. stores vitamins and minerals ( ie. iron, copper and zinc)
8. makes cholesterol
9. produces heat

Question 23

what is bile

Answer 23

formed in the liver and stored in the gall bladder, formed by the remains of red blood cells, yellow/green viscous fluid, composed of water, bile salts and bile pigments, enters duodenum through the bile duct

Question 24

the role of bile

Answer 24

1. emulsifies lipids for digestion

2. neutralises chyme

Question 25

the end products of digestion

Answer 25

carbohydrates —> monosaccharides(glucose)
proteins —> amino acids
lipids —> glycerol & fatty acids