human nutrition

Question 1

what is a balanced diet

Answer 1

getting all the right nutrients in correct proportions

Question 2

how is diet related to age/sex/activity

Answer 2

Children Below 12: Require more calcium

Teenagers: Highest calorie Intake

Adults: Balanced meal with less calories

Pregnant Women: more iron, calcium and folic acid

Males: Generally, require more energy

Question 3

what is malnutrition

Answer 3

A condition caused by eating an unbalanced diet.

Question 4

forms of malnutrition

Answer 4

Overnutrition: balanced diet but eating too much of everything

Undernutrition: having too little food

Eating foods in incorrect proportions

Question 5

effects of malnutrition

Answer 5

Starvation: losing strength & finally dying because of lack of food

Coronary heart disease: eating too much fats which are rich in saturated fatty acids and cholesterol, may lead to heart attack

Constipation: lack of roughages in food causes constipation because roughages are indigestible and form bulks. Friction between bulks and walls of intestine stimulate the peristalsis

Obesity: Eating too much fats and carbohydrates leads to their storage in storage in the body mainly in the forms of fats and causing an increase in body weight. This can cause; heart attack, stroke, joint pain, mobility impairment, high blood pressure

Question 6

use of carbohydrates

Answer 6

energy

Question 7

use of fats

Answer 7

Source of energy, building materials, energy store, insulation, buoyancy, making hormones

Question 8

use of proteins

Answer 8

Energy, building materials, enzymes, haemoglobin, structural material (muscle), hormones, antibodies

Question 9

use of vitamin c

Answer 9

Protect cells from ageing, production of fibres

Question 10

use of vitamin d

Answer 10

Absorption of calcium

Question 11

use of calcium

Answer 11

Development and maintenance of strong bones and teeth

Question 12

use of iron

Answer 12

Making haemoglobin

Question 13

use of fiber

Answer 13

Provides bulk for faeces, helps peristalsis

Question 14

use of water

Answer 14

Chemical reactions, solvent for transport

Question 15

what are the deficiencies

Answer 15

Vitamin C: Scurvy; loss of teeth, pale skin & sunken eyes

Vitamin D: Rickets; weak bones and teeth

Calcium: Rickets; weak bones and teeth, also poor clotting of blood, spasms

Iron: Anaemia: Fatigue (less iron → less haemoglobin → less oxygen transported → less respiration → less energy)

Question 16

ingestion alimentary canal

Answer 16

taking substances (e.g. food, drink) into the body through the mouth.

Question 17

egestion alimentary canal

Answer 17

passing out of food that has not been digested, as faeces, through the anus.

Question 18

digestion alimentary canal

Answer 18

the break-down of large, insoluble food molecules into small, water soluble molecules using mechanical and chemical processes

Question 19

mouth alimentary canal

Answer 19

contains teeth used for mechanical digestion, area where food is mixed with salivary amylase & where ingestion takes place

Question 20

salivary glands alimentary canal

Answer 20

produce saliva which contains amylase and helps food slide down oesophagus

Question 21

oesophagus alimentary canal

Answer 21

tube-shaped organ which uses peristalsis to transport food from mouth to stomach

Question 22

stomach alimentary canal

Answer 22

has sphincters to control movement into and also has pepsin (a protease) to break down proteins into peptides, it also kills bacteria with hydrochloric acid. They also have elastic walls.

Question 23

small intestine alimentary canal

Answer 23

tube shaped organ composed of two parts the:

Duodenum: fats are emulsified by bile, and digested by pancreatic lipase to form fatty acids and glycerol. Pancreatic amylase and trypsin (a protease) break down starch and peptides into maltose and amino acids

Ileum: Maltase breaks down maltose to glucose. This is where absorption takes place; adapted by having villi and microvilli.

Question 24

pancreas alimentary canal

Answer 24

produces pancreatic juice which contains amylase, trypsin and lipase and hydrogencarbonate.

Question 25

liver alimentary canal

Answer 25

produces bile, stores glucose as glycogen, interconverting them to keep glucose concentration constant. Also carries out interconversion of amino acids (transamination), deamination and removal of old red blood cells and storage of their iron. Also, site of breakdown of alcohol and other toxins.

Question 26

gall bladder alimentary canal

Answer 26

stores bile from liver

Question 27

bile alimentary canal

Answer 27

• produced by liver and stored in gall bladder, its role is to emulsify fats, to increase surface area for the action of enzymes
• in neutralising the acidic
  mixture of food and gastric juices entering the
  duodenum from the stomach, to provide a
  suitable pH for enzyme action

Question 28

large intestine alimentary canal

Answer 28

tube shaped organ composed of two parts:

Colon: organ for absorption of minerals and vitamins, and reabsorbing water from waste to maintain body’s water levels

Rectum: where faeces are temporarily stored

Question 29

anus alimentary canal

Answer 29

ring of muscle which controls when faeces is released.

Question 30

diarrhoea cause and cure

Answer 30

Diarrhoea: when not enough water is absorbed from the faeces

To cure this is to give oral rehydration therapy

One of these this infectious by a bacterium causing the diseases cholera (spreads rapidly)

The cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water into the gut, causing diarrhoea, dehydration and loss of salts from the blood

Question 31

incisor

Answer 31

Rectangular shape, sharp for cutting and biting

Question 32

canine

Answer 32

Sharp-pointed for holding and cutting

Question 33

premolar

Answer 33

Blunt for chewing and crushing

Question 34

molar

Answer 34

Blunt chewing and crushing. Two roots

Question 35

structure of a tooth

Answer 35

Enamel: the strongest tissue in the body made from calcium salts

Cement: helps to anchor tooth

Pulp cavity: contains tooth-producing cells, blood vessels, and nerve endings which detect pain.

Dentine: calcium salts deposited on a framework of collagen fibres

Neck: in between crown and root, it is the gums

Question 36

tooth decay stages

Answer 36

• plaque hardens to form tartar
• acid wears out surface of the enamel (takes time/not painful)
• erosion is faster in the dentine because it is softer (faster))
• erosion hits the pulp, where nerves and blood vessels are (very painful)

Question 37

prevention of tooth decay

Answer 37

Eating food with low sugar content

Regular and effective teeth brushing to remove plaque

Finishing a meal with a crisp vegetable and a glass of water`

Question 38

what is chemical digestion

Answer 38

Where enzymes are used to break down large insoluble substances such as proteins into smaller soluble substances like amino acids so that they can be absorbed.

Question 39

use of amylase

Answer 39

breaks down starch into maltose, it is produced in the pancreas (but also in the salivary gland)

Question 40

use of protease

Answer 40

breaks down proteins to peptides (done by pepsin) then into amino acids (done by trypsin). Pepsin comes from the stomach and trypsin comes from the pancreas.

Question 41

use of lipase

Answer 41

breaks down lipids into fatty acids and glycerol, produced by the pancreas.

Question 42

use of hydrochloric acid

Answer 42

Denaturing enzymes in harmful microorganisms in food

Giving the optimum pH for pepsin activity

Question 43

what is absorption

Answer 43

Movement of digested food molecules through wall of the intestine into the blood or lymph.

The small intestine is the region for absorption of digested food.

Question 44

adaptations of small intestine

Answer 44

The small intestine is folded into many villi which increase the surface area for absorption. One villus will have tiny folds on the cells on its outside called microvilli.

More surface area means more absorption can happen

Question 45

structures in villi

Answer 45

Capillary: transports glucose and amino acids

Vein: delivers absorbed products to liver via hepatic portal vein.

Gland: produces enzymes

Lacteal: absorbs fatty acid and glycerol

Epithelium: only one cell thick for faster transport. The cells of the epithelium are folded to form microvilli.

Question 46

function of small intestine and colon

Answer 46

Small intestine and colon absorb water

The small intestine absorbs 5–10 dm3 per day

The colon absorbs 0.3–0.5 dm3 per day

Question 47

digestion of starch in the alimentary canal

Answer 47

amylase is secreted into the alimentary canal
and breaks down starch to maltose
– maltose is broken down by maltase to
glucose on the membranes of the epithelium
lining the small intestine