gastrointestinal system Flashcards
What are the secretions and functions of the mouth and pharynx?
secretions:
- salt and water
- mucus
- amylase
functions:
- chewing, swallowing
- lubrication
- lubrication
what are the secretions and functions of the oesophagus?
secretions:
- mucus
functions:
-move food to stomach
- lubrication
what are the secretions and functions of the stomach?
secretions:
- HCL
- Pepsin
- mucus
functions:
- release to intestine
- protein digestive enzyme
- kill microbes
what are the secretions and functions of pancreas?
secretions:
- enzymes, bicarbonate
functions: - digest CHO, fats, proteins
- neutralise HCL entering small intestine
what are the secretions and functions of the liver?
secretions:
- bile salts, bicarbonate, organic waste, products, metals
functions:
- secretion of bile
- neutralise HCL entering small intestine
- elimination of faeces
what are the functions of the gall bladder?
functions:
- store and concentrate bile between meals
what are the secretions and functions of the small intestine?
secretions:
- enzymes, salt/H20, mucus
functions:
- lubrication
- food digestion
- digestion/absorption
what are the secretions and functions of the large intestine?
secretions:
- mucus
functions: - lubrication
- absorption salt, h20
- storage of undigested matter
what are the 4 major tissue layers of the GI tract wall?
- mucosa
- submucosa
- muscular externa
- serosa
what are the 4 processes of the GI system?
- digestion
- secretion
- absorption
- motility
what is the first process of the GI system?
Digestion.
mechanical breakdown= crushing and shearing by movement
chemical breakdown= hydrochloric acid and enzymes
what is the second process of the GI system?
Secretion.
- release of water, acids, enzymes, buffers and salts
- by epithelium of GI tract and glandular organs
what is the third process of the GI system?
Absorption.
- movement of nutrients across epithelium into blood stream or lymph
- active transport and transcellular transport
what is the fourth process of the GI system?
Motility.
- mixing and moving contents along the tract
what are the three phases of swallowing?
- buccal phase
- pharyngeal phase
- oesophageal phase
what is the empty volume in the stomach?
50ml
how much can the stomach expand to?
1.5L
what are the 4 regions of the stomach?
- cardia
- fundus
- body
- Pylorus/antrum
what are the functions of the stomach? (4)
- storage of ingested food
- secretion of gastric juice
- mechanical digestion of food into chyme
- production of intrinsic factor
what are the 3 phases of gastric secretion?
- Cephalic phase
- Gastric phase
- Intestinal phase
what is the cephalic phase?
- begins before food enters the stomach
- sensory signals from CNS
- Stimulates gastric secretions
what is the gastric phase?
- entry of food into the stomach
- short loop reflexes
- stimulates gastric secretions and smooth muscle contraction
what is the intestinal phase?
- entry of partially digested food into the small intestine
- reflexes that result in hormone secretion
- suppression of secretion and smooth muscle contraction
what does gastric emptying depend on?
- contraction of antral smooth muscle
- opening of pyloric sphincter
- relaxation of smooth muscle at entrance of small intestine
what is gastric emptying regulated by?
- CNS
- GI hormones
what is gastric emptying?
process of food leaving the stomach and entering the small intestine
what is the structure of the small intestine wall?
- circular folds
- villi and microvilli
- increase surface area
what is the Duodenum + accessory organ secretions
major site of enzymatic digestion
what are the 5 pancreatic enzymes?
- lipase
- amylase
- nucleases
- carboxypeptidase
- trypsin
