RE revise Flashcards
function of the small intestine
carbohydrate, fat, protein digestion and absorption
water and electrolyte transport
bile salt transport
function of the large intestine
storage
water reabsorption
when is the somatic motor act initiated
by willed decision to start chewing
becomes automatic
what hormone is released as a result of chewing and what is the effect this causes
gastrointestinal hormones
initial neurological activation
tell rest of gut food coming
whole process is controlled neurologically and hormonally
what are the constituents of saliva
water 99.5% (solvent)
ions (sodium, chloride, bicarbonate-buffer)
mucus (lubricant-solvent)
alpha-amylase (enzyme attach starch-digestion)
lysozymes (destroy bacteria-first point of protection, antibacterial action)
what are the functions of saliva
aids speech - facilitate tongue movement
oral hygiene - flush food residues
buffering - bicarbonate buffers neutralise acids
what controls saliva production
spontaneous
parasympathetic nerve endings
what is the gastric juice composed of
water HCl pepsinogen intrinsic factor mucous
what is the HCl for in the gastric juice
chemical attack on food
antiseptic
what is the pepsinogen for in the gastric juice
pepsin secreted as pepsinogen (inactive precurser)
stomach acid activates pepsin
what is the function of the parietal cells in the gastric gland
secrete acid and intrinsic factor (need for vitamin B12 absorption in small intestine) only fundus and body
what is the function of the enteroendocrine cells in the gastric gland
secrete hormones into blood
what is the function of the chief cells in the gastric gland
secrete protein pepsinogen
what regulates the rate of stomach emptying
inhibitory signals from small intestine:
- enterogastric reflex
- secretin
- cholecystokinin
what is the enterogastric reflex
reflex between stomach and intestines
what prevents chyme moving from stomach to the duodenum
pylorus sphincter
exocrine pancreas function
provides main digestive fluid of small intestine
empties into duodenum via pancreatic duct/common bile duct
what does the pancreatic secretion consist of
water
bicarbonate
enzymes
what are the enzymes in the pancreatic secretion
trypsin(OGEN) chymotrypsin(OGEN) amylase lipase nuclease STORED INACTIVE - ZYMOGENS
when are the enzymes from the pancreatic secretion activated
when reach duodenum
what is involved in the neurological control of the pancreas
parasympathetic nerves
- acetylcholine
- vasoactive intestinal peptide
an example of bile - excretory
breakdown products of metabolism
e.g. haemoglobin, break down products are bile pigments
biliverdin (green)
bilirubin (red)
they’re converted to stercobilin (brown) (also use bacteria)
what does the enzyme disaccharidases do
completes carbohydrate digestion
what does the enzyme aminopeptidases do
complete protein digestion