GIT Flashcards
Identify the source action and regulation of Intrinsic factor
From Parietal cells
Facilitates Vit B12 absorption
Identify the source action and regulation of Gastric acid
Parietal cells
Lowers pH to optimal range for pepsin function
Release is stimulated by histamine, Ach, gastrin
and inhibited by PG, somatostatin, GIP
Identify the source action and regulation of Pepsin
From Chief cells
Facilitates Protein digestion
Release is stimulated by vagal input and local acid
Identify the source action and regulation of Cholecystokinin (CCK)
From I cells of duodenum and jejunum
Increases GB contraction and Pancreatic secretion. Decreases gastric emptying.
Release is stimulated by increased presence of fatty acids and amino acids
Identify the source action and regulation of Cholecystokinin (CCK)
From I cells of duodenum and jejunum
Increases GB contraction and Pancreatic secretion. Decreases gastric emptying.
Release is stimulated by increased presence of fatty acids and amino acids/ monoglycerides in the duodenum
Identify the source action and regulation of Somatostatin
From D cells in pancreatic islets , GI mucosa
Inhibits release of ALL GI hormones
Release stimulated by acid and inhibited by vagus
In Cholelithiasis , pain worsen after eating fatty foods due to?
Increased secretion of Cholesystokinin
Alkaline pancreatic juice in duodenum neutralizes gastric acid, allowing pancreatic enzymes to function.
Secretin
Very inhibitory hormones- Anti GH
Somatostatin
This GI secretion is used to treat VIPomas and carcinoid tumors
Somatostatin
Destruction of this GI secretion will result in Pernicious anemia
Intrinsic factor
Inadequacy of this GI secretion predisposes to a high risk of Salmonella
Gastric Acid
Pesin by H+
Pepsinogen
This part of GI wall decreases diameter
Circular muscle (think circle)
This part of GI tract shortens a segment
Longitudinal muscle (think length)
Structure of the wall of GI tract
Epithelial cells- For secretion or absorption
Muscularis mucosa
Circular muscle- reduce diameter
Longitudinal muscle- shortening of a segment
Submucosal plexus (Meissner’s plexus and myenteric plexus)- Comprise the enteric nervous system, coordinate motility, secretory and endocrine functions of GIT
These cells of GI tract are responsible for absorption and secretion
Epithelial cells
This part of GI tract wall Comprise the enteric nervous system, coordinate motility, secretory and endocrine functions of GIT.
Submucosal plexus (Meissner’s plexus and myenteric plexus)
Describe the Intrinsic Innervation (enteric nervous system)
100 millions neurons
Coordinate information from PNS and SNS to GIT
Uses local reflexes to relay information within GIT
Controls most functions e.g. motility and secretion even in the absence of extrinsic innervation - “ Gut brain”
Myenteric plexus (Auerbach’s plexus)- Controls Motility
Submucosal plexus ( Meissner’s plexus)- Controls Secretion and blood flow
This Coordinates information from PNS and SNS to GIT and Uses local reflexes to relay information within GIT
Intrinsic Innervation (enteric nervous system)
Controls Motility
Myenteric plexus (Auerbach’s plexus)
Controls Secretion and blood flow
Submucosal plexus ( Meissner’s plexus)
Four “official” GI hormones are
gastrin
cholecystokinin (CCK)
secretin
glucose-dependent insulinotropic peptide (GIP).
GI hormones release from endocrine cells of GI mucosa into _________________, enter ________________ and have physiological actions on target tissues.
portal circulation
general circulation