digestion Flashcards
balanced diet
provides sufficient energy 4 needs.
provides molecules/materials for metabolism
provides nutrients:carbs vitamins, minerals, proteins, fats, fibre water
-in correct/right proportions
chemical and mechanical digestion
chemical digestion is break down of food molecules into smaller ones using enzymes. to fit through gut wall. insoluble to soluble
-mechanical provides larger sa for chemical digestion and bread food Ito smaller pieces sans chemical change via teeth muscle. also speed up chemical digestion, make easier to swallow and churn digestive juices.
proteins
lipids
carbs
dietary fibres
broken down to make amino acids which are used to form enzymes and other proteins needed by cells for growth and repair. sources include egg, milk products, cheese, yoghurt, meat, fish , legume, nuts and seeds
needed to release energy in cells to enable all life processes to take place. eg rice bread potatoes pasta yam
lipids fat deposited just below skin for insulation to maintain body temp. also a store of energy for times the diet does not contain enough energy for daily needs. eg meat (for fat) and lipids also come I oils, milk products, nuts, avocados , oily fish
dietary fibre made from cell walls of [;ants eg lady veg such as cabbage, unrefined grains like brown rice, whole grown wheat. adds bulks to food so can easily be moved along digestive system via peristalsis. prevent constipation and bowel cancer
energy content experiment
water importance
solvent for dissolving enzymes, food, makes food easier to chew, softens in saliva use chemical digestion, without diarrhoea and dehydration
VITAMINS
vitamin a
helps cells grow, keeps skin healthy, helps eyes see in poor light
liver, red and orange veg, eg carrots, butters and fish oil (FOLB)
night blindness
vitamin c
for healthy skin, teeth and gums and keep lining of blood vessels healthy
citrus fruit, green veg, potatoes PGC
scurvy, bleeding gums and wounds don’t heal properly
Vitamin D
strong bones and teeth, helps produce hormone controlling uptake of calcium from food
fish, eggs, liver, cheese, milk CLEMS
rickets, softening of the bones
bile
neutralises stomach acid for optimum ph ad emulsifies lipid
villi stricture
-lacteal
-microvilli on cells
-cells once cell thick
-lots o capillaries
-goblt cells
duodenum and ileum
first section where food coming out of stomach finishes being digested by enzymes produced here and also secreted by pancreas. ph 6.57
ileum where absorption of digested good.
colon
mouth
oespahgus
pancreas
liver
absorbs water and minerals that haven’t been absorbed (undigested) to produce faeces which are stored in the rectum and removed through anus
-mechanincal digestion takes place teeth chew food to break into smaller pieces increase SA; ratio. amylase enzyme in saliva start digesting starch into maltose
oesophagus tube that connects mouth to the stomach where bolus goes after being swallowed. peristalsis push it down
secretes digestive enzymes and also alkaline fluid into duodenum for digestion
deamination, bile (emulsify fats large droplets into smaller) excess glucose stores as glycogen
peristalsis
circular muscles and longitudinal muscles contrast antagonistically
circular muscles above contract to push food
Circular muscles contract to reduce the diameter of the lumen of the oesophagus or small intestine
Longitudinal muscles contract to reduce the length of that section the oesophagus or the small intestine
contraction of circular muscles behind food mass
contraction of longitudinal muscles ahead of food mass
contractions o circular muscle mass pushed food forward
Waves of muscle contraction that pass along the gut. Behind the food, circular muscles contract, longitudinal muscles relax, and the gut narrows pushing the food along.
