Gastric barrier, gastric secretion

Question 1

The production of high concentration of hydrogen in gastric juices also requires _________.

Answer 1

backlift of hydrogen into the mucosa

Question 2

What prevents the backlift of acid secretion into mucosa?

Answer 2

Gastric barrier

Question 3

What is an acid barrier made of?

Answer 3

alkaline mucus
tight junctions between epithelial cells

Question 4

The gastric acid barrier may be damaged by?

Answer 4

Toxic substances (Alcohol, aspirin, NSAIDs)

Question 5

When the gastric barrier is damaged, what will happen?

Answer 5

secreted acid leaks down an electrochemical gradient into the mucosa causing mucosal damage

[Acid that is secreted leaks into the mucosa, leading to damage due to an electrochemical gradient.]

Question 6

Three primary stimuli in gastric acid secretion

Answer 6

Gastrin
Histamine
Acetylcholine

Question 7

Hormone released by G-cells

Answer 7

Gastrin

Question 8

Gastrin is released in response to:

Answer 8

• GRP
• Presence of oligopeptides in gastric lumen

Question 9

Gastrin is carried through the bloodstream to the ____________.

Answer 9

fundic glands

Question 10

Gastrin binds to parietal and chief cells to ___________________.

Answer 10

activate secretion

Question 11

Gastrin binds to ECL to ________________.

Answer 11

release histamine

Question 12

This hormone is released from enteric nerve endings in the fundus

Answer 12

Acetylcholine

Question 13

What can Acetylcholine stimulate?

Answer 13

Pepsinogen, HCl, and mucus
CAN parietal and chief cell

Question 14

Gastrin and Histamine strongly stimulate ______________.

Answer 14

acid secretion

Question 15

Gastrin and Acetylcholine promote secretion by _______________.

Answer 15

elevating cytosol calcium

Question 16

Gastrin, histamine, and acetylcholine bind to distinct receptors on _______________.

Answer 16

basolateral membrane

Question 17

Histamine promotes secretion by ___________.

Answer 17

Increasing cAMP

Question 18

This pathway means small changes in stimuli can result in high secretion

Answer 18

synergistic pathway

Question 19

Therapeutically, secretions can be inhibited by?

Answer 19

blocking one trigger

Question 20

an example of widely used therapies

Answer 20

histamine 2 antagonist

Question 21

These are produced by chief cells

Answer 21

pepsinogen and lipase

Question 22

This has no digestive activity but becomes activated in response to contact with a certain enzyme.

Answer 22

Pepsinogen is inactive but is activated in contact with HCl

Question 23

The active form of pepsinogen

Answer 23

Pepsin

Question 24

Pepsin functions as

Answer 24

a proteolytic enzyme that initiates protein digestion

Question 25

optimum acidity of pepsin

Answer 25

pH of 1.8 to 3.5

Question 26

pepsin is inactive at the pH level of what?

Answer 26

pH >5

Question 27

Stimulation of pepsinogen secretion occurs in response to what?

Answer 27

Acetylcholine from vagus nerve

Question 28

Pepsinogen is heavily influenced by _______.

Answer 28

amount of acid

Question 29

These are produced by parietal cells along with HCl

Answer 29

Intrinsic factor

Question 30

Intrinsic factor is essential for the absorption of?

Answer 30

Vitamin B12 in ileum

Question 31

What is destructed in chronic gastritis?

Answer 31

parietal cells destruction

Question 32

What is developed in chronic gastritis?

Answer 32

achlorhydria
pernicious anemia

Question 33

What is the reason for pernicious anemia?

Answer 33

failure of RBC to mature due to Vitamin B12 absence