Flashcards in Physiology and Pharmaxology of the small and large intestine Deck (66)
Describe the length of the different parts of the small intestine
Duodenum - 25cm
Jejunum - 2.5m
Ileum - 3m
What happens in the small intestine
Major site for digestion and absoprtion
Receives chyme from the stomach, pancreatic juice from pancreas and bile form the gall bladder
How does the small intestine move remaining residues to the large intestine
Through the ileocaecal valve
In which part of the small intestine does most of the absorption and digestion occur?
How do pancreatic secretions and bile secretions enter the small intestine?
Through the sphincter of Oddi
What moves into the large intestine?
Unabsorbed electrolytes, water and indigestible residue (cellulose)
What is the sphincter between the small intestine and the large intestine
What controls the opening of the ileocaecal valve
The hormone Gastrin
In what 3 ways is the surface area of the small intestine increased?
Circular folds of Kerckring
What is the name of the absorptive cells?
What 7 peptide hormones are secreted from endocrine cells within the mucosa
Glucaogon-like insulinotropic peptide (GIP)
Glucagon like peptide 1
Where is gastrin secreted from
From G cells of gastric antrum and duodenum
Where is CCK secreted from?
From I cells of duodenum and jejunum
Where is secretin secreted from?
S cells of duodenum
WHere is motilin secreted?
From M cells of duodenum and jejunum
It has a special purpose in migrating the motor complex
Where is GIP secreted
an incretin from K cells of duodenum and jejunum
It causes an increase in gastric motility and serves as an incretin (feedforward signal)
Where is GLP-1 secreted
an incretin from L cells of the gut
Where is Ghrelin secreted
from Gr cells of the gastric antrum, small intestine and elsewhere (pancreas)
Where do all peptide hormones act on
G protein couple receptors
What is the role of Ghrelin
To release a hunger signal as a feedforward mechanism to prepare the body for food
What is the name given to the jucie of the small intestine
What will cause the release off the intestinal juice
Any stimulatory act on the GI tract
What are some of the control mechanisms related to the secretions of the small intestine
Distension / irritation if acid is present
Parasympathetic activity - change in ACh
Secretions of the small intestine include:
Mucus - for protection/ lubrication
Aqueous salt - for enzymatic digestion
No digestive enzymes
What does excessive activity cause?
Secretory diarrhoea (cholera)
What is the function of the ATPase in the basolateral membrane
To maintain a low intracellular concentration of sodium
Cysitic fibrosis patients may suffer from what in GI
a decrease in secretion of succus entericus
Segmentation in the duodenum is primarily due to what?
distension due to Chyme entering
What is triggered by gastrin from the stomach
What is the alternative name for this?
Segmentation in the empty ileum