organisation

what is a tissue, organ, and organ system?

tissue: group of cells with a similar structure and function

organ: group of tissues working together for a specific function

organ system: organs which work together to form organisms

what are the main organs in the digestive system and what are their functions?

mouth: food is chewed, enzymes in saliva digest starch into smaller sugar molecules

oesophagus: food passes down

stomach: enzymes digest proteins, contains hydrochloric acid. stays in stomach for 7 hours, churning motion turns food to fluid, increasing surface area for enzymes to digest

small intestine: chemicals from liver and pancreas pass through, pancreas releases enzymes which continue digestion of starch and protein and begin lipids, liver releases bile to speed up digestion of lipids

what happens during digestion?

enzymes break down large molecules, carbohydrates, proteins, and lipids, into small molecules so they can be absorbed by the blood stream