Human Nutrition Flashcards
Autotrophs
Make their own food eg plants via photosynthesis
Heterotrophs
Take food from their environment eg animals + fungi
Parasites
Take food from other sources eg fleas/ pathogenic bacteria
Saprophytes
Take food from dead sources eg decay causing fungi and bacteria
What do animals without a digestive system need
A full range of digestive enzymes in each cell
Alimentary canal
Long tube starting at the mouth ending at the anus
Ingestion
Taking food into the digestive system
Digestion
Breakdown of food
Absorption
Digested food enters bloodstream
Egestion
Removal of unabsorbed food
Incisors
At the front of the mouth, shaped like chisels - scissors
Canines
Long, pointed, fang like, tear food
Premolars
Large, flat, crush + grind food
Molars
Large, at the back, crush and grind food
Dental formula
2(I²⁄₂ C ¹⁄₁ P²⁄₂ M³⁄₃)
Mechanical digestion
Chewing + grinding of teeth on food
Chemical digestion
Occurs in the mouth by amylase (saliva)
Saliva contains
Water, salt, mucus, lysozyme, microorganisms + amylase
Amylase optimum pH
pH7
Amylase function
Breaks down starch into maltose
How food leaves the mouth
Food forms a bolus which is pushed back into the pharynx. Epiglottis makes sure food goes down the esophagus
Peristalsis
A wave of muscular contractions of the alimentary canal that moves content + mixes food with stomach secretions. Forces food from large intestine to rectum
How does fibre help peristalsis
Fibre from cellulose helps peristalsis absorbs + stores water, expanding waste + stimulating stomach muscles
What is the stomach
A musclar mag that holds + digest food
