Lecture 11 - small intestine Flashcards
When do we get rumbling or a series of peristaltic waves?
men - 91 mins
women - 89 mins
what is rumbling caused by?
It is caused by turbulent flow and so water that is falling on air causes bubbles and sounds
where does most of the absorption of nutrients occur?
in the small intestine
where does most of the digestion occur?
before the small intestine
When does chyme move into the small intestine?
0-3 hours after entering the stomach
how long does it take for chyme to move through the small intestine?
1-6 hr because it is 6 m
where is digested food absorbed?
into the blood stream and lymphatic system
what occurs in the duodenum?
absorption and digestion
what occurs in the jejunum?
absorption and digestion
what occurs in the ileum?
absorption
what is the conduction rate in the small intestine?
1 cm/min
what is the small intestine influenced by in regards to the nervous system and hormones?
- enteric nervous system
- hormones: gastrin, cholecystokinin, secretin
SA in small intestine? from just cylinder to circular folds to villi to microvilli
cylinder - relative SA: 1 and actual SA (m2): 0.33
circular folds- 3 and 1
villi - 30 and 10
microvilli - 600 and 200 m2
3 fold to 10 fold to 20 fold
Surface area of small intestine is 200 m2
total of 600 fold increase
Organisation of gut wall?
lining the lumen - absorptive cells
below - neurral and muscular components
blood and lynph vasculature is abundant to transport absorbed nutrients
by projecting into the lumen, the villi ….. SA for …… of nutrients
- increases
- absorption
Microvilli ….. the villi to …. SA
- fringe
- increase
what is digestion in the small intestine aided by?
it is aided by exymes and fluid that is secreted by the pancreas
what doe exocrine cells of the pancreas secrete?
digestive enzyme?
what do duct cells secrete?
bicarbonate
how are secretions from the liver and pancreas delivered to the duodenum?
through the sphincter of oddi
What do acini and duct cells secrete?
acini - secrete enzymes
duct - secrete bicarbonate
what are acini and duct cells stimulated by?
acini - CCK and ACh
duct - secretin
what is pancreatitis?
inflammation of the pancreas
where does intestinal fluid come from?
it comes from the pancreas and liver
