the digestive system Flashcards
the mouth
mobility: mastication of food by teeth and tongue
digestion–> amylase produced by salivary glands breaks down starch
absorption: non
secretion: amylase
osephagus
mobility- peristalsis
digestion- null
secretion: of mucosa (lube)
absorption: null
stomach
motility: contraction beings in the funds where s.muscle is stimulated- 3 sub units of the stomach fire APs; either tonic or phasic
absorption- some e.g. water
digestion- pepsin hydrolyses proteins and contraction produces chyme
s.intestine
motility: peristalsis
secretion: proteases, carbhohdrases and lipase
absorption: sugars, amino acids and fatty acids by villi
digestion- secretion, peristalsis, absorption
l.intestine
motility: segmentation contractions, antiperistalric and mass movement
secretion: mucosa and bicarbonate
absorption: water
digestion: removes waste product
accessory organs
liver- bile an blood processor gall bladder-storage of bile pancreas- enzymes appendix stores healthy bacteria salivary glands
polysaccharides digestion
broken down to disaccharides and other smaller sugars e.g. maltose by amylase in the saliva.
-then further broken down by enzymes found on the brush boarder to monosaccharides
monosaccharides
galactose
glucose
fructose
fat molecule
3 fatty acids 1 glycerol
fat present in s intestine..
stimulates the pancreas to release lipase and the gall bladder to release bile
pro enzyme of pepsin
pepsinogens–> acid content of the stomach activates pepsinogens to pepsins
functions of the appendix
- protect good bacteria
e. g. when an individual has diarrhoea and loses lots of bacteria, the appendix can store good bacteria that can help re-populate the digestive system to keep you healthy
patients who have had their appendix removed are..
4x more likely to have irritation in their l intestine
where interstitial cells of canal located
fundus (pacemaker cells)
BER
basic electrical rhythm 3 per min
where are enzymes and acid produced in the stomach
cardia
what character of the stomach means that its capacity can increase so much
the rugae
where does most mixing and churning occur in the stomach
antrum
pyloric antrum
nearer body
pyloric canal
empties into the duodenum
mains parts of s.intestine
duodenum
jejunum
iieum
main parts of large intestine
cecum, appendix, ascending transverse and descending colon, sigmoid and anus and rectum
how can too much fatty foods cause acid reflux
not due to an excess of acid but due to a malfunction of the gastrosphogeal sphincter- e.g. if it loses tone it won’t fully close.
fatty foods causes heartburn due to two reasons:
1) lipids cause the LEA to relax, easier for reflux to occur
2) lipids cause pyloric valve to contract tighter, so food is held in the stretch for longer- higher chance of reflux
coeliac disease
an autoimmune disease- immune system mistake gluten for a pathogen and attack it.
This causes villi to be broken down and they lose their important surface area (flattened)
-can cause rapid weight loss due to less nutrient being absorbed
symptoms of eating too much fatty food
bloating
acid reflux and heartburn
increased risk of heart disease
to alleviate symptoms of coeliac disease
no gluten must be eaten
gastric emptying is largely controlled by factors in the…
duodenum
factors in the stomach that influence gastric emptying
- amount of chyme being stored
- stomach distention
- fluidity of the chyme
factors in the s.intestine that influence gastric emptying
-if fat, acid, hypertonicity, distention is in the s.intestine then it won’t signal to the stomach to empty
what causes diarrhoea
when water can not be absorbed by the bowels:
-bacteria, viruses may effect ion channels which mean water potential causes water to leave the blood and enter in lumen and not be absorbed.