Flashcards in Pancreatic & Biliary Secretions Deck (49)
What are the three parts of the small intestine?
What does the small intestine receive?
What structures make the small intestine ideal for absorption?
What does the duodenum secrete into the blood?
Gastrin - D cells
CCK - I cells - duodenum and jejunum
Secretin - S cells - duodenum
Motilin - M cells - duodenum and jejunum
Glucose-dependent Insulinotropic peptide - K cells of duodenum and jujenum
How much does the duodenum secrete a day?
What are the enhancing control mechanisms for secretion?
distension, irritation, gastrin and CCK, secretin and parasympathetic activity
What is the inhibitory control mechanism for secretion?
sympathetic nerve activity
What does the secretions from the small intestine contain?
no digestive enzymes
What transporters are involved in secretion?
Na-K ATPase - apical, NKCC - apical, CFTR - basolateral
What happens during segmentation?
chopping movements move chyme back and forth vigorously with alternating contractions and relaxations of segments of the circular muscle
What is the frequency of segmentation in the sm. intestine?
duodenum has 12/min, ileum has 9/min which moved food along
What is the gastroileal reflex?
where segmentation occurs in the empty ileum due to gastrin
What peristalic activities occur in the fasting state?
a few localised contractions
the migrating motor complex
What is the migrating motor complex?
occurs between meals 90-120mins
strong peristalic contractions passing length of small intestine
clears sm. intestine of undigested debris, mucus and sloughed epithelial cells
What triggers the migrating motor complex?
what inhibits the migrating motor complex?
feeding and vagal activity
gastrin and CCK
Where do the digestive enzymes from the pancreas come from?
What does the pancreas secrete for digestion?
aqeous NaHCO3 from duct cells
digestive enzymes from the acinar cells
What pancreatic enzymes are produced by the acinar cells?
What activates trypsinogen in the first instance?
where is enterokinase made?
the mucosal cells
What is the function of the aqeuos NaHCO3 secretion from the duct cells?
neutralises acid chyme
ideal pH for enzymes
protects mucosa from erosion by acid
CF patients have reduced secretion
What are the three phases of pancreatic secretion?
What occurs in the cephalic phase of pancreatic secretion?
increase vagal stimulation of acinar cells
What occurs in the gastric phase of pancreatic secretion?
distension -> vagovagal reflex resulting in parasympathetic stimulation of acinar and duct cells
What occurs in the intestinal phase of pancreatic secretion?
increased acid -> increased secretin -> increases NaHC03 from duct cells
increased fat/protein in duodenum -> increased CCK -> increases enzymes from acinar cells
What are the hepatic ducts?
left, right, common
What are the bile ducts?
Where do the secretions from the gall bladder, liver and pancrease all meet?
sphincter of oddi