Digestive System Flashcards
Digestion
The physical and chemical breaking down of food into its constituents molecules, which can be absorbed into the bloodstream
Ingestion
The process of taking in food (mouth)
Absorption
The passage of single biomolecules from the gut into the bloodstream
Assimilation
The movement of digested food molecules into the cells of the body where they are used
Ejestion
The getting rid of undigested material from the body.
Stages of Digestion
Ingestion Digestion Absorption Assimilation Ejestion
Physical/Mechanical Digestion
Teeth Muscle, e.g. muscle of the stomach chewing Churning Peristalsis
Buccal Cavity
Teeth or chewing (Mechanical Digestion)
Salivary Glands
Produces saliva to digest bolus of food (Chemical Digestion)
Oesophagus
Food to Stomach by peristalsis
a wave of muscular contractions
Stomach
Muscular bag lined with gastric glands
Secretes gastric juices
Churns and mixes food with gastric juices
Adaptions of stomach
Mucous - goblet cells - prevent self-digestion
Pepsinogen - zymogen cells - Inactive enzymes
Hydrochloric acid - oxyntic cells - Kills bacteria
Small Intestine
Duodenum, jejunum and ileum
Lined with villi
Each villus has 600 microvilli
Produces Vitamin B and K
Receives pancreatic juices from pancreas and bile from gall bladder
Absorption (glucose, amino acids, fatty acids)
Large Intestine
Holds food
Caecum and appendix - vestigial organs
Colon reabsorbs water
Faeces stored in rectum
Symbiotic Bacteria
Colon bacteria feed on wate in large intestine and produces Vitamin B and K