GI 04 Flashcards
From where gastric acid, secretion happen?
ATPase pump in our parietal cells which is in our stomach.
To get acid into our stomach what are the three mechanism happen ?
Neuronal (Acetylcholine ,M3), Paracrine (Histamine,H2) and Endocrine (Gastrin CCK2) all three things are happening to get acid in our stomach.
Where is the location of the receptors, responsible to bring acid in our stomach?
The receptors M3, H2 and CCK2 are located in the body and fundus in stomach.
Which cells are responsible for acid production in our stomach?
Parietal cell. It secretes H+ and cl-.
Chef cells secrets ?
Pepsinogen=> Pepsin (enzymes help break down our food)
What Goblet cells does in the stomach ?
Mucus production (to protect stomach).
What are the stages of Production of Gastric acid in our stomach?
Step 1
We think about the food we start producing gastric acid because of through stomach to a neuronal activity called parasympathetic preganglionic neurons traveling in the vagus nerves.
Through neuronal direct effect, Ach released on => Muscarinic receptor.
Indirectly Ach activates through the paracrine effect & released histamine to=> Histamine receptor.
Ach activates G cells and releases Gastrin=> Gastrin receptor by the endocrine effect.
Step 2
Food stretches the stomach walls then Mechanoreceptor activates and creates a neural reflex that activates acid secretion.
(Peptides and amino acids in) food stimulates G cells to release gastrin.
An empty stomach is an acidic environment after adding Food it makes the acidic environment less acidic or ph. gets up. Somatostatin is a natural process which shuts off the acid secretion. That means enough acid in there no need for more acid to digest the food.
Step 3
When food passes through and enters the duodenum,
Somatostatin in the intestinal phase activates a negative feedback mechanism to reduce further acid secretion.
Somatostatin released from antrum D cells Less than 3 ph.
Ach =Nurotransmitter.
Somatostatin released from?
Antrum D cells. When stomach acid is less than pH 3
Who turn on the proton pumps?
H2 M3 & CCk2 receptors in the parietal cell activates G protein couple receptor which then turns on the pump. The pump exchange H for K. Once we get H then Cl join and make HCl
What are the Gastric defences against acid ?
Oesophegeal Sphincter
Mucous Layer
Prostaglandin stimulate more mucous and turn down proton pump pathway and increase bicarbonate pathway.
Bicarbonate work as buffer to increase ph
What does prostaglandin do?
By stopping Prostaglandin which stops the Pump and no acid production.
Prostaglandin also increase secretion of mucous
Why we get gastric mucosal injury ?
When stomach fails to maintain protective factors as a result its aggravating factors cause stress to our stomach and when we loss the balance we experience gastric mucosal injury.
What is GORD?
Burning of Oesophagus with stomach acid which is also known as hurt burn.
It is a chronic condition
And common in pregnancy.
GORD: Symptoms ?
Hurtburn Cough
What if we do not stop GORD?
Can erode the esophagus and cause harm like ulcer or carcinomas(Cancer).
how many Types of Ulcer can occour in stomach?
Gastric and duodenal
Why Peptic ulcer happen in people
Acid bile and pepsin taking up the balance and your protective factors cant control as a result create hole in your stomach
Create ulcer or whole into the stomach
It 90 % h duodenum and 70 % stomach
What are the Red flag for Peptic ulcer ?
Vomiting black or tarry stools
Unexpected weight loss.
Main causative factors for causing Peptic Ulcer ?
Smoking excess alcohol
Genetic factor
NSAID
Why would you we be concerned about black or tarry stools ?
Sign of bleading old denatured blood in stomach or intestine or somewhere.
It can lead to cancer so need to treat asap after 10 years 5% cause cancer
So why we need to treat peptic ulcer ?
Because it may lead to stomach cancer so stop the risk of cancer
What is Zollinger Ellison syndrome?
Pancreatic gastrinomas. As a result severe gastroduodenal ulceration. A rare disorder, which stimulates the production of a huge amount of acid.
Symptoms of Zollinger Ellison syndrome ?
Abdominal pain, diarrhoea, aching, heartburn, vomiting
What is Stress-related mucosal injury?
A major body trauma only experiences stress to the body: i.e. people with intensive care.