Digestive System Flashcards
what cells line the GI tract
epithelium
give an example of an accessory organ
tongue, salivary glands, pancreas, liver, gallbladder
list the 7 activities of the digestive system
ingestion, mastication, deglutination, digestion, absorption, peristalsis, defecation
what is chyme?
soupy substance produced as a result of mastication + chemical digestion
describe the structure of the GI tract wall
serosa (epithelium), muscularis (smooth muscle) , submucosa (connective tissue with lymph nodules), mucosa (mucus + epithelium secretes enzymes)
where does most of the chemical digestion take place
small intestine (enzymes)
describe the structure of the muscle in the GI tract
smooth muscle which is circular and longitudinal
why is pepsinogen in an inactive form
to prevent it from digesting the digestive system itself as it digests proteins
what are the 4 regions of the stomach
cardia, fundus, body, pylorus
what are the longitudinal folds in the mucosa layer called
gastric folds/rugae
what do goblet cells secrete
protective mucous
what do parietal cells secrete
hydrochloric acid
what do chief cells secrete
pepsinogen
what do argentaffin cells secrete
serotonin, histamine and autocrine regulators
what do endocrine cells secrete (G cells)
secrete the hormone gastrin into the blood
what hormone controls the production of gastric juice
gastrin
What is the pH of the stomach?
pH 2
What is the pancreas?
A long gland that lies beneath the stomach and is surrounded by the curve of the duodenum. It produces pancreatic juices that contains digestive enzymes and an alkaline solution that helps neutralise the acidic chyme
How does the liver help with digestion?
It aids the digestion of lipids by secreting bile - bile salts (manufactured from cholesterol in the liver) emulsify lipids
Where are nutrients absorbed?
Small intestine
How do amino acids and monosaccharides pass into an epithelial cell of a villus in the intestines
By using a carrier molecule
Role of large intestine
To absorb sodium ions and water, to eliminate wastes and to provide a home for friendly bacteria
What vitamins do bacteria in the large intestine produce
Vitamin K
What is dietary fibre important for in the colon?
regular movement of faeces