Block 2 Lecture 16

Question 1

what are the principle/hollow organs of the GI tract

Answer 1

mouth, esophagus, stomach, small intestine, large intestine

Question 2

what are the accessory organs of the GI tract

Answer 2

salivary glands, liver, gallbladder, pancreas

Question 3

what is the function of the mouth and esophagus

Answer 3

mechanical disruption

Question 4

what is the function of the small intestine

Answer 4

1. absorbs and secretes salt and water (net result is absorption of 9-10 liters a day)
2. finish digestion of proteins, carbohydrates, and lipids

Question 5

through what substances does small intestine digest

Answer 5

pancreatic enzymes, hepatic bile, luminal disaccharides and luminal peptidases

Question 6

what is the function of the large intestine

Answer 6

1. final absorption of salt and water (.4-.5 liters/day)
2. modest role in regulation of K+ homeostasis
3. compacting and storage of stool before explusion

Question 7

what is the function of salivary glands

Answer 7

1. initiate digestion of carbohydrates through alpha amylase and fats through lingual lipase
2. lubrication via mucus (protein) and serous (watery) secretions

Question 8

what is the function of liver and gallbladder

Answer 8

secretion of bile( emulsifies fats; stored in liver, releasing .5 liters a day into duodenum)

Question 9

what is the function of the pancreas

Answer 9

secretion of pancreatic juice (1.5 liters a day) rich in HCO3- and enzymes

Question 10

what is a zymogen

Answer 10

a type of proenzyme which is converted into an enzyme when activated by another enzyme

Question 11

what are the secretory products of the exocrine pancreas

Answer 11

1. ) pancreatic juice

2. ) 15-100 grams of protein (20 distinct enzymes)

Question 12

what does pancreatic juice contain

Answer 12

water, salts, NaHCO3. (1.2-1.5 liters a day of isotonic pancreatic juice)

Question 13

what is the purpose of zymogens

Answer 13

to prevent the enzymes from digesting proteins in the cells in which they’re synthesized

Question 14

what are the inactive zymogens of principle pancreatic enzymes

Answer 14

trypsinogen-> trypsin
chymotrypsinogen -> chymotrypsin
procarboxypeptidase -> carboxypeptidase
proelastase -> elastase

Question 15

what are the active enzymes of principle pancreatic enzymes

Answer 15

pancreatic alpha amylase, pancreatic lipase, ribonuclease/deoxyribonuclease

Question 16

what is the purpose of bicarbonate in pancreatic juice

Answer 16

neutralizes the acid in gastric juice which facilitates action of pancreatic enzymes

Question 17

what is the mechanism of zymogen activation

Answer 17

enteropeptidase cleaves a peptide from trypsinogen forming active digestive enzyme trypsin. trypsin then activates other pancreatic zymogens

Question 18

where is enteropeptidase found

Answer 18

brush border of small intestine

Question 19

what is another name for enteropeptidase

Answer 19

enterokinase

Question 20

what is the function of endocrine glands

Answer 20

secrete their products, hormones, directly into blood

Question 21

what is the function of the endocrine pancreas

Answer 21

islets of langerhans are source of insulin (from beta cells) and glucagon (from alpha cells) which are secreted directly into blood

Question 22

what is the function of exocrine glands

Answer 22

secrete their products into ducts that lead to external environment

Question 23

what is the function of the exocrine pancreas

Answer 23

collection of lobules, each lobule is a collection of ducts each of which beings at an acinus. the watery secretion is delivered to outside of body

Question 24

what is the acinus the site of

Answer 24

formation of primary secretion of exocrine gland: salt and water

Question 25

what is the duct of an exocrine gland a site for

Answer 25

modification of the primary secretory product of acing cells. (isosmotic secretion)

Question 26

what is the fluid balance in humans per day

Answer 26

food and drink-2 liters
GI secretions- 7 liters
1.9 liters excreted as urine and sweat
0.1 excreted in feces

NET RESULT OF 2 LITERS IN 2 LITERS OUT THIS SI STEADY STATE