Ingestion and Digestion

Question 1

hormonal regulation of feeding behavior

Answer 1

promote thirst: ADJ and aldosterone
promote hunger: glucagon and ghrelin
promote satiety: leptin and cholecystokinin

Question 2

in the oral cavity, what occurs?

Answer 2

mastication occurs, which starts the mechanical digestion of food; while salivary amylase and lipase start the chemical digestion. food is formed into a bolus and swallowed

Question 3

the pharynx

Answer 3

this connects the mouth and posterior nasal cavity to the esophagus

Question 4

what does the the esophagus do? where does the food enter through?

Answer 4

it propels food to the stomach using peistalsis. food then enters the sotmach through the lower esophageal (cardiac) sphincter.

Question 5

the stomach

Answer 5

it has four parts to it: the fundus, body, antrum, and pylorus. It was a lesser and greater curvature and is thrown into folds called rugae. Numerous secretory cells line the stomach

Question 6

what type of cells reside in the stomach?

Answer 6

mucous cells, chief cells, parietal cells, G cells

Question 7

mucous cells

Answer 7

these produce bicarbonate-rich mucus to protect the stomach

Question 8

Chief cells

Answer 8

secrete pepsinogen, a protease activated by the acidic environment of the stomach

Question 9

Parietal cells

Answer 9

secrete hydrochloric acid and intrinsic factor, which is needed for vitamin B12 absorption

Question 10

G cells

Answer 10

secrete gastrin, a peptide hormone that increases HCl secretion and grastric motility

Question 11

what is chyme?

Answer 11

this is the result of mechanical and chemical digestion in the stomach

Question 12

where does chyme pass through?

Answer 12

the pyloric sphincter

Question 13

the first part of the small intestine: name and activity that occurs

Answer 13

the duodenum is the first part of the intestine and is primarily involved in chemical digestion

Question 14

what are some of the enzymes that reside in the duodenum and what is their activity?

Answer 14

• disaccharidases are brush-border enzymes that break down maltose, isomaltose, lactose, and sucrose into monosaccharides
• brush-border peptidases include aminopeptidase and dipeptidases
• enteropeptidase activates trypsinogen and procarboxypeptidases, initiating an activation cascade
• secretin stimulates the release of pancreatic juices into the digestive tract and slows motility
• cholecystokinin stimulates bile release from the gallbladder, release of pancreatic juices, and satiety