Physiology Flashcards
what does the small intestine receive from the stomach?
chyme - via the pyloric sphincter
what does the small intestine receive from the pancreas?
pancreatic juice
what does the small intestine receive from the gallbladder?
bile
what does the small intestine secrete?
intestinal juices and moves remaining residue to the large intestine
name the adaptations of the small intestine which increases surface area
arranged in circular folds
contains villi
villi contain microvilli
Name the peptide hormones that the small intestine secretes (7)
gastrin Cholecystokinin (CCK) Secretin Motilin Glucagon like insulinotropic peptide (GIP) Glucagon like peptide-1 (GLP 1) Ghrelin
which cells are the peptide hormones secreted from in the small intestine?
endocrine cells within the mucosa into the blood
where does gastrin come from?
G cells of the gastric antrum and duoenum
where does CCK come from?
cells of the duodenum and jejunum
where does secretin come from?
s cells of the duodenum
where does motilin come form?
m cells of the duodenum and jejunum
where does GIP come from?
K cells of the duodenum and jejunum
Where does GLP-1 come from?
incretin from L cells of the gut
Where does ghrelin come from?
Gr cells of the gastric antrumm, small intestine and pancreas
which receptors do peptide hormones from the small intestine act on?
g-protein coupled receptors
what does incretin do?
acts on b-cells of the pancreas to stimulate the release of insulin
Control mechanisms of the succus entericus
arrival of chyme
gastrin
CCK
secretin
parasympathetic nerve activity - enhances activity
sympathetic nerve activity - decreases activity
what does secretion of the small intestine contain?
mucous and aqueous salt
steps of mixing of chyme
- moved back and forth
- contraction and relaxation initiate by pacemaker cells
- segmentation of duodenum
- segmentation in the ileum (empty) triggered by gastrin
- overall net movement
what controls the segmentation of the small intestine during the mixing of chyme?
parasympathetic and sympathetic stimulation
what inhibits the migrating motor complex of peristalsis
feeding and vagal activity
what does peristalsis clear from the small intestine?
debris, mucus and endotheliac cells between meals
what are the components of the endocrine secretion of the pancreas?
insulin and glucagon onto the blood
what are the components of the exocrine secretion of the pancreas?
digestive enzymes and sodium bicarbonate
what do acinar cells secrete in the pancreas?
trypsinogen chymotrypsinogen procarboxypeptidase A and B pancreatic amylase pancreatic lipase
what does trypsinogen become in the duodenum?
trypsin (enterokinase is added)
what is autocatalysis
the process by which a substance catalyses its own production e.g. trypsin