Ch. 38: Structure and Function of the Digestive System Flashcards
Which of the following organs is NOT part of the alimentary or GI tract? Mouth Esophagus Stomach Liver
Liver
The liver is not part of the GI tract. The mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus are considered part of the GI tract.
Which of the following is NOT one of the three salivary glands? Thyroid Submandibular Sublingual Parotid
Thyroid
The three salivary glands include the submandibular, sublingual, and parotid.
Which of the following is TRUE regarding salivation?
Salivation is controlled by the parasympathetic nervous system.
Cholinergic fibers stimulate the salivary glands.
Atropine increases salivary secretion.
ß-Adrenergic stimulation decreases salivary secretion.
Cholinergic fibers stimulate the salivary glands
Salivary secretion is controlled by the sympathetic and parasympathetic systems but not by hormones. The parasympathetic system increases secretions, and an anticholinergic-like atropine actually makes the mouth dry. The ß-adrenergic stimulation also increases secretion.
Which of the following is TRUE regarding the esophagus?
The upper third is mixed striated and smooth muscle.
The middle third is innervated by motor fibers.
The lower third is innervated by striated muscle.
The lower third is innervated by preganglionic fibers from the vagus nerve.
The lower third is innervated by preganglionic fibers from the vagus nerve.
The upper third is striated muscle and is innervated by motor neurons. The middle third is striated and smooth muscle. The lower third is smooth muscle innervated by preganglionic fibers from the vagus nerve.
Which blood vessel provides blood to the stomach? Celiac artery Gastric artery Splenic artery Mesenteric artery
Celiac artery
A branch of the celiac artery supplies the stomach. The splenic vein drains the right side of the stomach, and the gastric vein drains the left.
Which of the following hormones is responsible for inhibition of the stomach contraction? Gastrin Motilin Secretin Cholecystokinin
Secretin
Secretin is responsible for inhibition by raising the threshold potential. Gastrin and motilin increase contraction by lowering the threshold potential of muscle fibers. Cholecystokinin causes relaxation in the esophagus.
Which cells of the stomach secrete hydrochloric acid and intrinsic factor? Parietal cells Chief cells G cells Enterochromaffin-like cells
Parietal cells
Parietal cells secrete hydrochloric acid and intrinsic factor. Chief cells secrete pepsinogen. G cells secrete gastrin in the antrum of the stomach. Enterochromaffin-like cells secrete histamine.
Which of the following is NOT one of the functions of stomach acid?
Dissolve food fibers
Act as a bactericide
Convert intrinsic factor into its active form
Convert pepsinogen into pepsin
Convert intrinsic factor into its active form
Intrinsic factor is secreted from parietal cells within the stomach. Acid is responsible for dissolving food fibers and acts against bacteria. It also cleaves pepsinogen to pepsin.
Which of the following is NOT part of the cephalic phase of gastric juice secretion? Smelling food Seeing food Tasting food Eating food
Eating food
The arrival of food in the stomach is the beginning of the gastric phase of secretion. The cephalic phase includes smelling, seeing, tasting, chewing, and swallowing food.
Which enzyme is responsible for breaking the end amino acids away from the ingested protein? Trypsin Chymotrypsin Lipase Carboxypeptidases
Corboxypeptidases
Carboxypeptidases break away the end amino acids. Trypsin and chymotrypsin hydrolyze the interior bonds of the large molecules. Lipase is a pancreatic enzyme.
Which enzyme is responsible for cleaving fatty acids from phospholipids? Cholesterol esterase Phospholipase Lipase Chylomicron
Phospholipase
Phospholipase cleaves fatty acids from phospholipids. Cholesterol esterase breaks cholesterol esters into fatty acids and glycerol. Lipase breaks down triglycerides to diglycerides, monoglycerides, free fatty acids, and glycerol. Chylomicrons are particles that consist of triglycerides covered with phospholipids.
When iron is being absorbed into the small bowel, to what protein is it bound in the epithelial cells? Transferrin Calcium phosphate Transcobalamin Ferritin
Ferritin
Ferritin is the protein to which iron is bound in epithelial cells. Initially it is bound to intestinal transferrin. Calcium phosphate and phosphoproteins bind iron in the intestinal lumen and reduce absorption. Transcobalamin is the protein carrier for vitamin B12 to enter the plasma.
Which of the following is NOT one of the four phases of digestion and absorption of fat? Emulsification and lipolysis Micelle formation Hydrolysis Fat absorption
Hydrolysis
Hydrolysis is not a function of digestion and absorption of fat. It is a part of protein digestion. The four phases of digestion and absorption of fat include emulsification and lipolysis, micelle formation, fat absorption, and resynthesis of triglycerides and phospholipids.
Which cells of the liver store lipids? Hepatocytes Sinusoids Lipocytes Kupffer cells
Lipocytes
Lipocytes store lipids. The hepatocytes are the functional cells of the liver. Sinusoids are small capillaries located between hepatocytes. Kupffer cells are phagocytes that line the sinusoids.
Which of the following is the appropriate description for unconjugated bilirubin?
It is bilirubin that binds to albumin.
It is found within the hepatocytes.
It is found at the terminal end of the ileum and the colon.
It is water soluble.
It is bilirubin that binds to albumin.
Unconjugated bilirubin binds to albumin and is lipid soluble. Conjugated bilirubin is water soluble and is secreted in the bile. In the hepatocytes unconjugated bilirubin turns into conjugated bilirubin after it combines with glucuronic acid. Urobilinogen is found in the ileum and colon.
