Human Nutrition - Digestion Flashcards
nutrition
the way in which an organism obtains and uses food
autotrops
organisms that can make their own food ie. green plants, but photosynthesis
heterotrops
organisms that canot make their own food and must get it from environment
herbivores
feed only on plants
carnivores
eat other animals
omnivores
eat both plants and animals
example of herbivore
cow
example of carnivore
dogs
example of omnivore
human
stages of human nutrition
- Ingestion
- Digestion
- Absorption
- Egestion
(assimilation)
ingestion
the taking of food into the alimentary canal i.e putting it into the mouth
digestion
the mechanical or chemical breakdown of food into smaller molecules so that it can be absorbsed
absorption
soluble products of digestion can now pass through the cells lining the small intestine into the blood and lymph systems
egestion
the removal of unabsorbed and undigested material from the digestive system (through the anus)
assimilation
the absorbed food is used to make new molecules of for release of energy
7 components of a balanced diet
carbohydrates, protein, lipids, vitamins, minerals, fibre, water
what is a balanced diet
the 7 components must be present in the right amounts
factors affecting amount of food required in a person
age- growing teenagers need more food than elders
activity levels- more if you exercise a lot
frequency of sugar and alcohol
restricted intake
frequency of dairy
2-3 a day
frequency of meat/fish/protein
2-3 a day
frequency of fruit and veg
3-5 a day
frequency of starchy carbs
6-11 a day
pH of mouth
7-8
type of digestion in mouth
chemical and physical
mechanical digestion
breakdown of large pieces of food by physical or mechanical ways
mechanical digestion in the mouth
chewing action of the teeth
chemical digestion
chemical breakdown of food by enzymes
chemical digestion in mouth
amylase converts starch to maltose
human teeth types
incisors canines premolars and molars
incisor function
cutting
canine function
stabbing and tearing
premolar and molar function
chewing and grinding
dental formula for half mouth
I 22 C 11 P22 M33
how many teeth in adult whole mouth
32
herbivore teeth
broad, rigid premolars and molars
carnivore teeth
long sharp canines
salivary glands arranged in mouth
3 pairs of them
4 components of saliva
water and mucous (mucin)
salts
salivary amylase
lysozome
function of mucin in saliva
moisten and lubricate the food and make it easier to swallow
function of salts in saliva
provide neutral to slightly alkaline pH, optimum for amylase
function of salivary amylase in saliva
enzyme that converts starch to maltose
function of lysozome in saliva
helps kill microorganisms eg.bacteria
name for ball of food made in the mouth
bolus
flap of skin and cartilage in throat
epiglottis
peristalsis
involuntary muscle contractions of the gut wall which moves food
what is the stomach
a muscular bag that receives food from the oesophagus
pH of stomach
2