Section Test:Digestion

Section Test:Digestion

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1. How is the stomach lining protected from the caustic acid pH of its contents?

The stomach lining is not protected from acid and frequently develops ulcers as a result.
It releases a hormone called gastrin, which stops gastric juice.
Parietal cells secrete a protective buffer to neutralize hydrochloric acid.
Mucous cells secrete a protective lubricant into the stomach.
The acid is quickly neutralized when it combines with pepsinogen to make pepsin.
→ Ulcers are the consequence of the acid destroying the inner lining. Pepsin does not neutralize the acid contents of the stomach, it in fact is an enzyme that only function under acidic conditions. Parietal cells secrete HCl and do not produce a protective buffer.

2. The digestive “accessory gland” that produces pepsinogen is the

gastric gland
liver
intestine
pancreas
salivary gland
→ Folds in the mucosa lining of the stomach form small secretory glands where cheif cells reside and produce pepsinogen, the precursor of pepsin.

3. The villi and microvilli of the small intestine both help to

increase the rate of absorption
produce the acid needed to digest protein
produce the bile to digest fat.
move the undigested food to the large intestine.
lubricate food by releasing water
→ absorption of nutrients is entirely related to the surface area on which passive and active transport can occur. Numerous folds (villi) help to increase this surface area and thus increase the rate of diffusion.

4. What is found in acid chyme?

bile
amylase
lipases
food before it is chewed
pepsin
→ Chyme is the digestive mixture of food that is made in the stomach which includes the chewed food along with the juices that have been secreted from the mouth and the stomach.

5. The digestive “accessory gland” that produces bile is the

gastric gland
liver
intestine
pancreas
salivary glands
→ The pancreas produces bile which is then stored in the gull bladder and secreted into to the duodenum.

6. The best description of chyme is

a fluid that is composed of polysaccharides and triglycerides
a fluid composed of proteins, polysaccharides, fats and gastric secretions
a fluid composed of salivary secretions, polysaccharides, fats, and proteins
a fluid composed of triglycerides, enzymes, and disaccharides
a fluid composed of proteins, fats, and pancreatic secretions

7. What is the function of colonic bacteria in the colon?

to digest any undigested polysaccharide fibers
to digest any undigested triglyceride fats
to digest any undigested polypeptides
to phagocytose any virus that invades
→ The colonic bacteria reside in the colon in a mutualistc symbiosis with the human body. They feed off the material that our body can't digest (polysaccharide fibers such as cellulose) and help in a protective way by competing with invading bacteria for space (they however do NOT act like immune cells which phagocytose parasites).

8. Heartburn is usually caused by the effects of gastric juice on the

heart
esophagus
stomach
small intestine
→ heart burn, or acid reflex, occurs when the acidic juices of the stomach are accidentally splashed into the esophagus causing damage to the unprotected cell lining.

9. The pyloric sphincter is found between the

duodenum and jejunum.
ileum and cecum.
stomach and esophagus.
pharynx and esophagus.
stomach and duodenum
→ The pyloric sphincter is found at the exit of the stomach, while the Esophageal sphincter (or Cardia) is the valve at the entrance of the stomach.

10. The pancreas is stimulated to release its exocrine secretions by

gastrin.
the HCl in chyme.
trypsinogen.
VIP.
secretin and CCK

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