human nutrition Flashcards
what is a balanced diet
getting all the right nutrients in correct proportions
how is diet related to age/sex/activity
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
what is malnutrition
A condition caused by eating an unbalanced diet.
forms of malnutrition
Overnutrition: balanced diet but eating too much of everything
Undernutrition: having too little food
Eating foods in incorrect proportions
effects of malnutrition
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
use of carbohydrates
energy
use of fats
Source of energy, building materials, energy store, insulation, buoyancy, making hormones
use of proteins
Energy, building materials, enzymes, haemoglobin, structural material (muscle), hormones, antibodies
use of vitamin c
Protect cells from ageing, production of fibres
use of vitamin d
Absorption of calcium
use of calcium
Development and maintenance of strong bones and teeth
use of iron
Making haemoglobin
use of fiber
Provides bulk for faeces, helps peristalsis
use of water
Chemical reactions, solvent for transport
what are the deficiencies
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)
ingestion alimentary canal
taking substances (e.g. food, drink) into the body through the mouth.
egestion alimentary canal
passing out of food that has not been digested, as faeces, through the anus.
digestion alimentary canal
the break-down of large, insoluble food molecules into small, water soluble molecules using mechanical and chemical processes
mouth alimentary canal
contains teeth used for mechanical digestion, area where food is mixed with salivary amylase & where ingestion takes place
salivary glands alimentary canal
produce saliva which contains amylase and helps food slide down oesophagus
oesophagus alimentary canal
tube-shaped organ which uses peristalsis to transport food from mouth to stomach
stomach alimentary canal
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.
small intestine alimentary canal
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.
pancreas alimentary canal
produces pancreatic juice which contains amylase, trypsin and lipase and hydrogencarbonate.
liver alimentary canal
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.
gall bladder alimentary canal
stores bile from liver
bile alimentary canal
- 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
large intestine alimentary canal
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
anus alimentary canal
ring of muscle which controls when faeces is released.
diarrhoea cause and cure
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
incisor
Rectangular shape, sharp for cutting and biting
canine
Sharp-pointed for holding and cutting
premolar
Blunt for chewing and crushing
molar
Blunt chewing and crushing. Two roots
structure of a tooth
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
tooth decay stages
- 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)
prevention of tooth decay
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`
what is chemical digestion
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.
use of amylase
breaks down starch into maltose, it is produced in the pancreas (but also in the salivary gland)
use of protease
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.
use of lipase
breaks down lipids into fatty acids and glycerol, produced by the pancreas.
use of hydrochloric acid
Denaturing enzymes in harmful microorganisms in food
Giving the optimum pH for pepsin activity
what is absorption
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.
adaptations of small intestine
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
structures in villi
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.
function of small intestine and colon
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
digestion of starch in the alimentary canal
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
