Gastric Secretion Flashcards
What does the body of stomach do?
Storage,mucus production,HCL,Pepsinogen, intrinsic factor
What is the antrum for
Mixing/Grinding and secreting gastrin (hormone that controls acid and pepsin secretion
What do: -Mucus neck cells -Chief cells -Parietal cells all secrete?
Mucus neck : Mucus
Chief cells: Secretes pepsinogens
Parietal cells: Secretes HCL and makes intrinsic factor
How does HCL form in the stomach?
CO2 diffuses and combines w H2O –>H2CO3 witht he help of carbonic anhydrase . –> This product is short lived as it breaks into HCO3 and H ion. –> as a result theH ion is pumped out and K ion is moved in through a pump. –> HCO3 on the other hand moves to blood through a CL-HCO3 pump and the later leaves the cell to form HCL with water in the paracellular pathway. HCO3 causes blood to slightly alkalise as well.
What secretes Gastrin
G cells
Histamine acts on which receptors
H2 receptors which act through Gs pathway to turn ATP to cAMP that acts on protein kinase
Ach acts on what receptors and what does that do
Muscarinic receptors that allow Ca in cell and act on protein kinase to pump H out of cell
How do you switch off mechanism to Decrease H pumping to stomach
Prostaglandins act on GI pathway and decreases the process
What are the three mechanisms that control gastric acid secretion
- Neurocrine (Vagus/ local reflexes)
- Endocrine ( gastrin)
- Paracrine (Histamine)
Distention of stomach acts on ___ that releases ___
Vagus nerve/ENS that release ACh that acts on parietal cells
Peptides in lumen act on?
G cells that secrete gastrin
gastin/Ach both act on ___ Cells that release ___
ECL cells that release Histamine that acts on partietal cells
What are enterogastrones?
Hormones released fom gland cells in duodenal mucosa such as : Secretin, Cholecystokinin (CCK) and GIP.
These are released in response to acid, hypertonic solutions, fatty acids or monoglycerides in duodenum
What do enterogastrones do?
Act up to collectively prevent further acid build up in duodenum
How do enterogastrones work?
By inhibting gastric secretion or by reducing gastric motility and emptying or by contracting the pyloric sphincter
