Chapter 33 Flashcards
Alimentary Canal
pharynx
esophagus
stomach
small intestine
large intestine
Accessory glands
secrete digestive juices through ducts; include salivary glands, pancreas, liver and gallbladder
Small Intestine Organs
pancreas
liver
Food from the small intestine travels to the
hepatic portal vein
Lipids from the small intestine travel to the
lymphatic system
Nutrients from the large intestine
hepatic portal vein
Pepsin breaks down proteins into
small polypeptides
Pancreatic trypsin and chymotrypsin
break down amino acids adjacent to certain amino acids
Pancreatic carboxypeptidase
break down small peptides amino acids
Dipeptidases, carboxypeptidase, and aminopeptidases
break down individual amino acids
Pancreatic nucleases break down
DNA and RNA into nucleotides
Nucleotidases break
nucleotides into nucleosides
Nucleosidases and phosphates break down
nucleosides into nitrogenous bases, sugars and phosphates
pancreatic lipase breaks down
fats into glycerol, fatty acids, monoglycerides
Mucous role in the stomach
provide a protective coat
Chief role in the stomach
create the active enzyme pepsin
Chief secretion
pepsinogen
Chief cells secrete pepsinogen and parietal cells secrete _ and _ separately into the lumen
H+
Cl-
H+ and Cl- react to form ___ which activates the inactive pepsinogen into the active enzyme ______
HCl
Pepsin
Pepsin activates more __________ to convert into pepsin, starting a chain reaction. This is an example of ________
pepsinogen
+ feedback
True or False: HCl would damage parietal cells if it was secreted inside the parietal cells
true
True or False: Pepsin is an inactive enzyme, while pepsinogen is active
false
In the small intestine, the first 10 inches is the
duodenum
Its ability to absorb and secrete is due to increased surface area because of projections in the lumen called _____ and ________ on epithelial cells
villi
microvilli
______ breaks down triglycerides into fatty acids and monoglycerides which diffuse into epithelial cells and reform into triglycerides
lipase
before entering the lympathic system triglycerides are incorporated into water-soluble particles called
chylomicrons
Cholecytoskinin is released in the
duodenum
Cholectoskinin acts on the
pancreas; releases digestive enzymes
Cholecytoskinin also acts on the
gallbladder; releases bile
Secretin is released in the
duodenum
Secretin acts on the
pancreas
Secretin’s response
it releases bicarbonate
True or False: when chyme is rich in fat, CCK and secretin can also inhibit the release of gastric juice and slow digestion
true
Monosaccharides __________, and polysaccharides __________.
are single monomer units; are made of many monosaccharides chained together
How do glucagon and insulin differ?
Insulin is secreted from the pancreas, whereas glucagon is secreted from the liver.
Which of the following hypothetical situations might result in a blood sugar level that is too high?
An individual has an autoimmune disorder that destroys the beta cells of the pancreas.
An individual’s insulin receptors are defective.
When digested, proteins are broken down into _____.
amino acids
When digested, fats are broken down into _____.
both glycerol and fatty acids
Starch is a type of _____.
polysaccharide
Your small intestine can absorb ____ without its being further digested.
fructose
Starch can be broken down into the disaccharide known as _____.
maltose
What is the main component of gastric juice?
water
A fat molecule is composed of two types of smaller molecules, including only one molecule of _______
glycerol
A fat molecule also includes one, two, or three _____ molecules.
fatty
A fat molecule with only one fatty acid is called a
monoglyceride
A fat molecule with three fatty acids is called a triacylglycerol, or a
triglyceride
fatty acid includes a carboxyl group (-COOH) at one end as well as a long __________________
hydrocarbon tail
The hydrocarbon chains found in fats store a lot of energy. They also make fats ________ , or insoluble in water.
hydrophobic
Which structure is not part of the alimentary canal?
salivary glands
Which process is not required for an animal to obtain energy from food?
excretion
One advantage of having a tube-like digestive tract is that digestion of all compounds can take place simultaneously down the tract.
false
The liver is a component of the alimentary canal.
false
Which of the following is an example of positive feedback in the lumen of the stomach?
Pepsin digests molecules of pepsinogen, producing more pepsin.
How do hydrogen ions (H+) and chloride ions (Cl–) get into the lumen of the stomach?
H+ is actively transported from parietal cells into the lumen, while Cl– diffuses from parietal cells into the lumen.
A researcher added a mixture of animal proteins to a physiological buffer solution (pH 7.4) in a test tube incubated at 37°C. The researcher then added purified pepsin to the mixture, but even after several hours, the proteins were not digested. Which of the following would explain this result?
the pH was too high
What is one function of mucus in the lumen of the stomach?
It protects the epithelium from being digested by gastric juice.
The epithelium that lines the stomach has many deep infoldings, or pits. In what way do these pits function as glands?
They secrete gastric juice into the main chamber of the stomach.
