BSC 2086C Exam 4 Chapters 24, 25, 26 Questions With
Complete Solutions
Hydrochloric Acid (HCl)
Gastric juice has a high concentration of HCl and a pH as low as
0.8. This is more acidic than the battery acid of a car, and low
enough to dissolve tooth enamel or cause a chemical burn on the
skin. HCl is a strong acid, gives up most of its hydrogen ions
and can markedly lower the pH of a solution.
Secretin (Hormone)
Is produced by the same regions of the small intestine, mainly in
response to the acidity of chyme from the stomach. Stimulates
the ducts of both the liver and pancreas to secrete an abundant
sodium bicarbonate solution. In the pancreas, this flushes the
enzymes into the duodenum. Sodium bicarbonate buffers the
HCl arriving from the stomach.
Full Stomach pH
Higher than usual, ranging from about 3 to 7 pH depending on
the amount and composition of the food. Food buffers the strong
stomach acid, causing the pH to rise temporarily from its normal
fasted state of 1.5 to 3.5. The pH will then drop back down as
food is processed, and more acid is secreted.
Empty Stomach pH
The pH of an empty stomach is highly acidic, typically ranging
from 1.5 to 3.5 pH. This acidic environment is created by HCl
, and is maintained even when the stomach is empty. Is crucial for
killing bacteria and beginning the digestion of proteins.
Intrinsic Factor
Parietal cells secrete a glycoprotein called intrinsic factor that is
essential for the absorption of vitamin B12 by the small
intestine. Binds vitamin B12, and the intestinal cells then absorb
this complex by receptor-mediated endocytosis. Without vitamin
B12, hemoglobin can't be synthesized and anemia develops.
Hepatopancreatic Sphincter
Regulates the passage of bile and pancreatic juice into the
duodenum. Between meals, this sphincter is closed and prevents
the release of bile into the intestine.
Bilirubin
The principal bile pigment, derived from the decomposition of
hemoglobin from old erythrocytes that have died.
Peyer's Patches
Aggregated lymphoid nodules. The ileum has prominent
lymphoid nodules in clusters, which are readily visible to the
naked eye and become progressively larger approaching the
large intestine. Are populations of lymphocytes to fight
pathogens.
Haustra
The muscle tone of the taeniae coli contracts the colon
lengthwise and causes its wall to bulge, forming pouches called
haustra. Are conspicuous in colonic X-rays of living patients.
Complete Solutions
Hydrochloric Acid (HCl)
Gastric juice has a high concentration of HCl and a pH as low as
0.8. This is more acidic than the battery acid of a car, and low
enough to dissolve tooth enamel or cause a chemical burn on the
skin. HCl is a strong acid, gives up most of its hydrogen ions
and can markedly lower the pH of a solution.
Secretin (Hormone)
Is produced by the same regions of the small intestine, mainly in
response to the acidity of chyme from the stomach. Stimulates
the ducts of both the liver and pancreas to secrete an abundant
sodium bicarbonate solution. In the pancreas, this flushes the
enzymes into the duodenum. Sodium bicarbonate buffers the
HCl arriving from the stomach.
Full Stomach pH
Higher than usual, ranging from about 3 to 7 pH depending on
the amount and composition of the food. Food buffers the strong
stomach acid, causing the pH to rise temporarily from its normal
fasted state of 1.5 to 3.5. The pH will then drop back down as
food is processed, and more acid is secreted.
Empty Stomach pH
The pH of an empty stomach is highly acidic, typically ranging
from 1.5 to 3.5 pH. This acidic environment is created by HCl
, and is maintained even when the stomach is empty. Is crucial for
killing bacteria and beginning the digestion of proteins.
Intrinsic Factor
Parietal cells secrete a glycoprotein called intrinsic factor that is
essential for the absorption of vitamin B12 by the small
intestine. Binds vitamin B12, and the intestinal cells then absorb
this complex by receptor-mediated endocytosis. Without vitamin
B12, hemoglobin can't be synthesized and anemia develops.
Hepatopancreatic Sphincter
Regulates the passage of bile and pancreatic juice into the
duodenum. Between meals, this sphincter is closed and prevents
the release of bile into the intestine.
Bilirubin
The principal bile pigment, derived from the decomposition of
hemoglobin from old erythrocytes that have died.
Peyer's Patches
Aggregated lymphoid nodules. The ileum has prominent
lymphoid nodules in clusters, which are readily visible to the
naked eye and become progressively larger approaching the
large intestine. Are populations of lymphocytes to fight
pathogens.
Haustra
The muscle tone of the taeniae coli contracts the colon
lengthwise and causes its wall to bulge, forming pouches called
haustra. Are conspicuous in colonic X-rays of living patients.
