Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
24 Cards in this Set
- Front
- Back
|
Stomach Functions
|
Storage: temporary reservoir for meal
Secretion of H+: to kill microorganisms and convert pepsinogen to pepsin Secretion of intrinsic factor for vitamin B12 absorption Secretion of water for lubrication and provide aqueous suspension for nutrients Motor activity for mixing secretions with ingested food |
|
|
Cardia of the stomach does not
|
secrete enzymes
|
|
|
Components of gastric juice
|
HCL
Pepsinogen Instrinsic factor Mucus |
|
|
HCiniates
|
initiates digestion, activates pepsin
|
|
|
What happens when parietal cells get activated
|
the vesicles agglomerate (tubulovesicular membrane) and create a larger vesicle in which the enzymes are dumped
|
|
|
Mechanism of acid secretion
|
K/H transporter is the primary transport to secrete K and absordb H. Cell becomes more alkaline and in order to maintain pH homeostasis, HCO3 is secreted
|
|
|
Accumulation of K in the cell leads to
|
inhibition of K/H transporter and hence acid secretion is inhibited as well. Cl is secreted by Cl channel
|
|
|
G cells are present in
|
antrum of stomach and duodenum
|
|
|
Neurons can stimulate parietal cells and ECL via
|
Ach
|
|
|
Acid secretion inhibitory path
|
D cells sense high concentration of protons, and then D cells secrete somatostatin which directly binds parietal cells to inhibit secretion. Also somatostatin binds G cells to inhibit gastrin secretion
|
|
|
Gastrin receptor
|
binds to CCKb (theres homology between gastrin and CCK, CCK has 2 receptors a and b, b has a higher affinity gastrin).
|
|
|
M3 is a receptor for
|
Ach
|
|
|
PLC and IP3, DAG, PKC get activated by
|
gastrin, and Ach and gastric acid secretion is induced.
|
|
|
Histamine activates adenyl cyclate, cAMP and PKA which leads to
|
gastric acid secretion. Better to have gastrin and Ach together to increase acid secretion
|
|
|
Somatostatin and Prostaglandins activate
|
a G inhibitory protein so acid secretion is reduced.
|
|
|
Acid secretion happens
|
all the time in the stomach.
|
|
|
Gastric acid secretion stimulants
|
Distention and peptones
|
|
|
Although ENS is the brain gut, it’s not well developed in the stomach as it is in the esophagus, so
|
CNS involvement in those areas is neded.
|
|
|
Low pressure maintenance even when theres a lot of food in the stomach is carried by
|
vagus
|
|
|
When acid is secreted goes up through mucous forcefully not through
|
diffusion
|
|
|
Peptic ulcers
|
Erosions of the mucous membranes of the stomach or duodenum produced by action of HCl
|
|
|
Zollinger-Ellison syndrome
|
Ulcers of the duodenum are produced by excessive gastric acid secretions
|
|
|
Acute gastritis
|
Histamine released by tissue damage and inflammation stimulate further acid secretion
|
|
|
Helicobacter pylori:
|
Bacterium that resides in GI tract that may produce ulcers
|
