PNB 2265 EXAM 3 QUESTIONS AND
ANSWERS
Integrated meal response - Correct Answers -path of food from mouth to rectum
Integrated meal response phases - Correct Answers -cephalic
gastric
intestinal
colonic
Two parts of GI tract - Correct Answers -alimentary canal
accessory organs
Alimentary canal - Correct Answers -mouth
esophagus
stomach
small intestines
large intestines
rectum
Accessory organs of GI trac - Correct Answers -salivary glands
liver
pancreas
gallbladder
Peritoneum - Correct Answers -serous membrane that surrounds GI system that is
different from others bc it folds in on itself and btwn the folds are fat deposits
-made of parietal and visceral with peritoneal fluid between
Parietal peritoneum - Correct Answers -layer of serous membrane that lines the walls of
the abdominal cavity
Visceral peritoneum - Correct Answers -layer of serous membrane that covers the
surface of organs
Order of tissue layers in GI tract (wall to lumen) - Correct Answers -serosa
muscularis
submucosa
mucosa
Serosa - Correct Answers -outer layer of tube that is connective tissue wrapper that
holds things together, protects them, and is site of attachment
,Muscularis externa - Correct Answers -smooth muscle layer that has two layers, one
longitudinal outer layer and one circular inner layer with a myenteric plexis layer btwn
Muscularis externa layers (lumen to outer) - Correct Answers -circular layer
myenteric plexis
Longitudinal layer
Myenteric plexis - Correct Answers -nerve tissue layer btwn the layers of the muscularis
externa that controls smooth muscle contraction and is under involuntary control by
parasympathetic stimulation
Longitudinal layer muscularis externa - Correct Answers -outer layer that gives you
contractions that will make the tube shorter or longer (controls length)
Circular layer muscularis externa - Correct Answers -inner layer that controls radius of
the tube
Submucosa - Correct Answers -loose connective tissue that binds things together. Has
large blood vessels, large lymphatic vessels (galt), and nerves
Galt - Correct Answers -submucosa (gut) associated lymphatic tissue that has a lot of
immune cells since this is a point of entry for pathogens
Mucosa layers - Correct Answers -muscularis mucosae
lamino propria
epithelium layer
Muscularis mucosae - Correct Answers -mucosa layer that is the muscle part that
shapes the surface of the mucosal layer
Lamina propria - Correct Answers -connective tissue mucosal layer with tiny vessels
(capillaries) and small lymphatic vessels
Epithelium layer (mucosa) - Correct Answers -mucosa layer closest to lumen that has
specializations depending on where in the GI tract
-has enterocytes, enteroendocrine cells, and mucin-producing cells
Submucosal plexus - Correct Answers -nerves in the submucosa layer
Enterodendocrine cells - Correct Answers -secretory cells in epithelia of mucosa
Enterocytes - Correct Answers -cells that do absorption in epithelia of mucosa
Mucin-producing cells - Correct Answers -mucous producing cells in epithelia of mucosa
Peristalsis - Correct Answers -motility of GI tract that produces forward movment
, -contraction of smooth muscle behind bolus to create high pressure behind and low
pressure in front
-found in esophagus, stomach, weak in small intestines, infrequently in large intestine
Segmentation - Correct Answers -Coordinating contractions in front and behind to
create mixing
-proximal and distal contractions
-faster frequency behind to still slightly push things forward
-primarily in small intestines
Phasic contractions - Correct Answers -quick contractions that produce movement
(peristalsis and segmentation)
Tonic contractions - Correct Answers -smooth muscles contracts and stays contracted
to prevent backflow
-is in sphincters
Smooth muscle contractions - Correct Answers -can contract more than other muscles
due to diagonal filaments and doesn't have to worry about refractory period
Smooth muscle contraction mechanism - Correct Answers -Uses MLCK to
phosphoryalte myosin chain and speed up ATP hydrolysis and promote contraction
-doesnt have tropomyosin or myosin head
Myosin Light Chain Kinase (MLCK) - Correct Answers -enzyme that when active can
phosphorylate myosin chain and speed up ATP hydrolysis in smooth muscle to promote
contraction
-anything that increases its activity promotes contraction
MLCK regulation - Correct Answers --Ca activates it and promotes contraction
-cAMP inhibits it and causes relaxation
Myosin light chain phosphatase (MLCP) - Correct Answers -removes a phosphate from
myosin chain and is inhibitory to smooth muscle contration
Phosphodiesterase - Correct Answers -breaks down cAMP
Which membrane does secretion in GI tract - Correct Answers -apical membrane,
closest to lumen
Which membrane does absorption in GI tract - Correct Answers -basal membrane
Secretion of bicarbonate ions - Correct Answers -in duct cells there is CO2 and H2O
which enzyme carbonic anhydrase will use to make H2CO3 which dissociates to H+
and HCO3-. H+ ion comes out basal surface in exchange for Na (using gradient)
through Na/H+ exchanger. Na/K pump on basal surface is then used to fix the gradient.
ANSWERS
Integrated meal response - Correct Answers -path of food from mouth to rectum
Integrated meal response phases - Correct Answers -cephalic
gastric
intestinal
colonic
Two parts of GI tract - Correct Answers -alimentary canal
accessory organs
Alimentary canal - Correct Answers -mouth
esophagus
stomach
small intestines
large intestines
rectum
Accessory organs of GI trac - Correct Answers -salivary glands
liver
pancreas
gallbladder
Peritoneum - Correct Answers -serous membrane that surrounds GI system that is
different from others bc it folds in on itself and btwn the folds are fat deposits
-made of parietal and visceral with peritoneal fluid between
Parietal peritoneum - Correct Answers -layer of serous membrane that lines the walls of
the abdominal cavity
Visceral peritoneum - Correct Answers -layer of serous membrane that covers the
surface of organs
Order of tissue layers in GI tract (wall to lumen) - Correct Answers -serosa
muscularis
submucosa
mucosa
Serosa - Correct Answers -outer layer of tube that is connective tissue wrapper that
holds things together, protects them, and is site of attachment
,Muscularis externa - Correct Answers -smooth muscle layer that has two layers, one
longitudinal outer layer and one circular inner layer with a myenteric plexis layer btwn
Muscularis externa layers (lumen to outer) - Correct Answers -circular layer
myenteric plexis
Longitudinal layer
Myenteric plexis - Correct Answers -nerve tissue layer btwn the layers of the muscularis
externa that controls smooth muscle contraction and is under involuntary control by
parasympathetic stimulation
Longitudinal layer muscularis externa - Correct Answers -outer layer that gives you
contractions that will make the tube shorter or longer (controls length)
Circular layer muscularis externa - Correct Answers -inner layer that controls radius of
the tube
Submucosa - Correct Answers -loose connective tissue that binds things together. Has
large blood vessels, large lymphatic vessels (galt), and nerves
Galt - Correct Answers -submucosa (gut) associated lymphatic tissue that has a lot of
immune cells since this is a point of entry for pathogens
Mucosa layers - Correct Answers -muscularis mucosae
lamino propria
epithelium layer
Muscularis mucosae - Correct Answers -mucosa layer that is the muscle part that
shapes the surface of the mucosal layer
Lamina propria - Correct Answers -connective tissue mucosal layer with tiny vessels
(capillaries) and small lymphatic vessels
Epithelium layer (mucosa) - Correct Answers -mucosa layer closest to lumen that has
specializations depending on where in the GI tract
-has enterocytes, enteroendocrine cells, and mucin-producing cells
Submucosal plexus - Correct Answers -nerves in the submucosa layer
Enterodendocrine cells - Correct Answers -secretory cells in epithelia of mucosa
Enterocytes - Correct Answers -cells that do absorption in epithelia of mucosa
Mucin-producing cells - Correct Answers -mucous producing cells in epithelia of mucosa
Peristalsis - Correct Answers -motility of GI tract that produces forward movment
, -contraction of smooth muscle behind bolus to create high pressure behind and low
pressure in front
-found in esophagus, stomach, weak in small intestines, infrequently in large intestine
Segmentation - Correct Answers -Coordinating contractions in front and behind to
create mixing
-proximal and distal contractions
-faster frequency behind to still slightly push things forward
-primarily in small intestines
Phasic contractions - Correct Answers -quick contractions that produce movement
(peristalsis and segmentation)
Tonic contractions - Correct Answers -smooth muscles contracts and stays contracted
to prevent backflow
-is in sphincters
Smooth muscle contractions - Correct Answers -can contract more than other muscles
due to diagonal filaments and doesn't have to worry about refractory period
Smooth muscle contraction mechanism - Correct Answers -Uses MLCK to
phosphoryalte myosin chain and speed up ATP hydrolysis and promote contraction
-doesnt have tropomyosin or myosin head
Myosin Light Chain Kinase (MLCK) - Correct Answers -enzyme that when active can
phosphorylate myosin chain and speed up ATP hydrolysis in smooth muscle to promote
contraction
-anything that increases its activity promotes contraction
MLCK regulation - Correct Answers --Ca activates it and promotes contraction
-cAMP inhibits it and causes relaxation
Myosin light chain phosphatase (MLCP) - Correct Answers -removes a phosphate from
myosin chain and is inhibitory to smooth muscle contration
Phosphodiesterase - Correct Answers -breaks down cAMP
Which membrane does secretion in GI tract - Correct Answers -apical membrane,
closest to lumen
Which membrane does absorption in GI tract - Correct Answers -basal membrane
Secretion of bicarbonate ions - Correct Answers -in duct cells there is CO2 and H2O
which enzyme carbonic anhydrase will use to make H2CO3 which dissociates to H+
and HCO3-. H+ ion comes out basal surface in exchange for Na (using gradient)
through Na/H+ exchanger. Na/K pump on basal surface is then used to fix the gradient.
