lecture 18

Question 0

pepsin function as

Answer 0

a active proteolytic enzyme in high acid medium. HCL is as necessary as pepsin for protein digestion

Question 1

pepsinogen is converted to it active form

Answer 1

through the contact HCl acid to form pepsin

Question 2

the secretion of histamine by the ECL is

Answer 2

due to the direct contact of ECL with parietal cells

Question 3

how is ECL stimulated

Answer 3

1 through the production of gastrin by the g cell
2 by the acetylcholine released from the stomach vagal nerve ending , or an hormonal substance secreted by the enteric nervous system.

Question 4

gastrin is secrete by the

Answer 4

the gastric cells or G cells in the pyloric gland located in the distal end of the stomach

Question 5

there are two form off gastrin

Answer 5

G 34 and G 17 , G 17 is more abundant

Question 6

the main stimulus or trigger for the production of G34 and G17

Answer 6

is the presence of amino acid.

Question 7

regulation of chief cells is by

Answer 7

the release of acetylcholine from the vagus nerve and stimulation of chief cell in response to acid in the stomach, affected by the intrinsic nervous system plexus

Question 8

the pancreas lies

Answer 8

parallel to and beneath the stomach

Question 9

pancreatic acini

Answer 9

secretes pancreatic digestive enzyme

Question 10

small ductules and larger duct from the pancreatic acini secret

Answer 10

large volumes of sodium bicarbonate

Question 11

pancreatic duct

Answer 11

where the combination of pancreatic enzyme and sodium bicarbonate flow through that then links with the hepatic duct before emptying into the duodenum through the ampulla vater surrounded by the sphincter of oddi

Question 12

pancreas has two region

Answer 12

endocrine region: islet of langerhans compose of a and B cells produces insulin and glycogen

Exocrine: produces digestive enzyme called pancreatic juices

Question 13

sphincter of oddi

Answer 13

a sphincter regulates the opening of ampulla of vater that empties into the duodenum

Question 14

bicarbonate has the role of

Answer 14

in acidify the chyme from the stomach into the duodenum

Question 15

the three most important pancreatic juices

Answer 15

trpsin, chymotrpisn, carboxypolypeptidase, these work in the small intestine but are produced by the pancreas

Question 16

The pancreatic amylase function is

Answer 16

is digesting carbohydrates by hydrolyzing starch, glycogen, and other carbohydrate except cellulose

Question 17

pancreatic lipase

Answer 17

hydrolyzes neutral fats into fatty acids and monoglycerides

Question 18

all the pancreatic juices are produced in the pancreas but function in the

Answer 18

small intestine

Question 19

Basic stimuli that cause the pancreatic secretion

Answer 19

acetylcholine; released by the PNS vagus nerve ending and other cholinergic nerves in the enteric nervous system .

cck: which is secreted by the duodenal and upper jejunal mucosa when foo enters the the small intestine.
secretin: secreted by the duodenal and jejunal when highly acid food enters the small intestine

Question 20

acetylcholine and cck stimulate

Answer 20

the acinar cells causing production of pancreatic juice

Question 21

secretin stimulate

Answer 21

secretion of large quantities of water solution of bicarbonate

Question 22

Bile formation occurs in the

Answer 22

liver

Question 23

bile contain two compounds

Answer 23

bile salts and bile acid, which helps to emulsify the large fat particles to be attacked by lipase, and aids in the absorption of fat end product through the intestinal mucosa membrane.

Question 24

first stage of bile secretion

Answer 24

the hepatocyte initial secretion contains large amount of bile acids and cholesterol and substance, it is secreted into the bile canaliculi

Question 25

2 stage of bile secretion

Answer 25

the bile flows through the canaliculi and empties into the terminal bile duct, then reaches the hepatic duct and common bile duct, from here the bile empties into the duodenum or divert through the cystic duct into the gallbladder

Question 26

the function of the gallbladder is to

Answer 26

store to the bile produced by the liver

Question 27

bile salt aids in

Answer 27

the digestion of fats and absorption of fats, formation of micelles , breakdown of red blood cells to form bilirubin

Question 28

Jaundice

Answer 28

is caused by the deposit of bilirubin, free or conjugate bilirubin in the extracellular fluid, this lead to the yellowness of body tissues and skin

Question 29

gallstone happen due

Answer 29

to the absorption of too much water

Question 30

cck and the gall bladder

Answer 30

it induces the contraction, causing the gallbladder to empty in the duodenum that is stimulated by fatty food

Question 31

Bile salt precursor is

Answer 31

cholesterol which can be converted to cholic acid or chenodeoxycholic acid, then conjugate with amino acid glycine and tauroine

Question 32

role of bile salt

Answer 32

1. act as a detergent or emulsifying function to decrease the surface tension, 2. helps with the absorption of fat through the formation of micelles

Question 33

first stage of secretion of bicarbonate ion

Answer 33

CO2 diffuses to the interior of the cell from the blood and, under the influence of carbonic anhydrase , combines with water to from carbonic acid, by dissociation of result in bicarbonate and h+ion then bicarbonate is actively transported with sodium through the luminal border of the cell into the lumen of the duct

Question 34

2 stage of secretion of bicarbonate ion

Answer 34

the hydrogen ion formed by dissociation of carbonic acid are exchanged for Na ion by secondary active transport, the Na is take to the pancreatic duct to provide electric neutrality for bicarbonate ions

Question 35

3 stage of secretion of bicarbonate ion

Answer 35

the overall movement of sodium and bicarbonate ions from the blood into the duct lumen creates an osmotic pressure gradient that casue osmosis forming an almost completely isomotic bicarbonate solution

Question 36

Brunner’s gland

Answer 36

is located in duodenum, it secrete alkaline mucus due to response of due to tactile or irritating stimulus on the duodenal mucosa , vagal stimulation cause increase secretion of the gland , and GI hormone( secretin)

Question 37

gland of lieberkuhn

Answer 37

located over the entire surface of the small intestine are small pits called the crypts of lieberkuhn that lie between the villi and are cover with epithelium composed of two types of Globlets cells( mucus) and enterocytes that secretes large amount of water and electrolyte.