Biology 5C

Digestive system

a coordinated system that breaks down food and delivers nutrients to cells

Ingestion

taking food into the body

Digestion

breaking down food into smaller molecules

Absorption

movement of nutrients into the bloodstream

Elimination

removal of undigested material

Amylase

acts on carbohydrates into smaller sugar molecules

Protease

acts on protein into amino acids

Lipase

acts on fats into fatty acids and glycerol

Oral cavity

food enters, teeth break down food, saliva breaks down carbs (amylase) and fats (lipase), tongue moves food into bolus

Oesophagus

hollow tube connecting mouth to stomach, peristalsis moves food down

Stomach

temporary storage tank, churns food, protease enzymes and HCl breaks down protein, becomes chyme

Small Intestine

primary site of digestion/absorption

Duodenum

digestive enzymes and bile aid digestion

Jejunum

absorbs nutrients into bloodstream

Ileum

final absorption of nutrients

Large Intestine

Final absorption of water, vitamins, and minerals, contains bacteria aiding digestion

Cecum

junction between small and large intestines

Colon

Water absorption, compacts waste

Rectum

Stores faeces before elimination

Anus

Final part of digestive tract, controls elimination of faeces

Salivary glands

Produce saliva that lubricates food for easier swallowing

Liver

Produces bile (physically breaks down fats into smaller droplets), detoxifies harmful substances

Gallbladder

stores and concentrates bile, releases bile into small intestine

Pancreas

produces digestive enzymes, secretes bicarbonate to neutralise stomach acid in small intestine

Appendix

located at the junction between the small and large intestines

Chewing

teeth grinds and tears food into smaller pieces, tongue moves it around

Churning

stomach muscles contract to mix food with gastric juices

Peristalsis

wave like contractions in oesophagus and intestines pushing food through digestive tract

Segmentation

muscular contractions mix chyme with digestive juices in small intestine

Herbivore

ruminant, a complex stomach with 4 chambers, long digestive tract to maximise nutrient absorption

Carnivore

simple stomach, single chambered stomach quickly digesting meat, small intestine adapted to protein and fat absorption

Omnivore

mixed digestive system, single chambered stomach but with adaptations to absorb plant and animal matter