Functions Of The Stomach

Question 1

What are the basic functions of the stomach?

Answer 1

Receive food as part of a short term storage facility, and disrupt food, via vigorous contractions of the smooth muscle, and continue digestion mainly by using proteins as well as dinsinfect

Question 2

What are the different areas of the stomach (top to bottom)

Answer 2

Cardia, fundus, the body, and the antrum

Question 3

What are some of the features of the histology of the stomach?

Answer 3

Abrupt transition of stratified squamous to columnar, due to the features of secretion, the mucosa and the submucosa are thrown into folds known as rugae, and there are lots of little holes in the submucosa

Question 4

What are the different types of cells found in the stomach?

Answer 4

The mucous cells, teh parietal cells, the chief cells and the g cells

Question 5

What are some of the features of the smooth muscle of the stomahc?

Answer 5

There is an extra oblique layer of muscle, contractions, mix grin contents, and move contents along,upper stomach has sustained contractions and helps to create a basal tone

Question 6

What are some of the functions of stomach smooth muscle?

Answer 6

Strong perstaislis mixes the stomahc contents, there are coordinate mvpovemtents with contractions about every 20 minutes, proximal to distal, and the shape of the stomach is larger proximal to smaller at the distal end and these causes the contents to accelerate and leave the lumps and stuff behind

Question 7

What is the proccess of receptive relaxation?

Answer 7

vagally mediated relaxation of the oral stomach, swallows food to enter the stomach withourpt raising the intra gastric pressure too much, prevents reflux of the stomach contents during swallow and the gastric mucosal folds maintain distension

Question 8

What substances kt the stomach secrete?

Answer 8

HCL, intrinsic factor, mucous, HCO3 and pepsinogen which then becomes pepsin

Question 9

What do parietal cells in the sotmahc secrete?

Answer 9

HCL and intrinsic factor

Question 10

What do g cells in the stomach secrete?

Answer 10

Gastrin

Question 11

What do enterochromffin like cells in the stomahc secreete?

Answer 11

Histamine

Question 12

What do chief cells in the stomach secrete?

Answer 12

Pesinpogen

Question 13

What do the d cells in the stomach secrete?

Answer 13

Somatosatitn

Question 14

What do the muclus cells of the surface and nexl of the stomach produce?

Answer 14

Stomachn

Question 15

What are some of the features of the gastric pits and the gastric glands?

Answer 15

There are surface mucous cells, mucous neck cells then pertial cells, chief cells and the eneteroendocrine cells spit into the gastric pit at the top and the gastric glands at the bottom

Question 16

What are the different secretory products of different oarts of the stomach?

Answer 16

The cardia is predominately involved in mucus secretion, the fundus and body is involved in the secretion of mucus, hcl and pepsinogen, pylorus is involved in the secretion of gastrin and somatostatin however there is lots of cross over

Question 17

What are the pariteal cells of the stomach stimulated by?

Answer 17

Gastrin, histamine and ACh

Question 18

What are the features of the control of HCl production?

Answer 18

Gastrin is released form the bloodstream, stimulates CCK production and the eneterochromfin like cells produce histamine, which stimulates the H2 receptors, the vagus nerve produces ACh and this stimulates the Mcr receptors

Question 19

How does the body inhibit HCl production?

Answer 19

Essentially by inhibiting g cells, when food leaves the stomach the pH drops as the food behaves as a buffer, the low pH activates the d cells that produce somatastatin that inhibits the G cells, and the reduction in stomach distension reduces the vagal activity

Question 20

How is gastrin secretion controlled?

Answer 20

By g cells, that are stimulated to produce gastrin by peptides and amino acids in the stomach lumen, and gastrin releasing peptide

Question 21

How is HCl produced fpby the stomach cells?

Answer 21

Water is split into H+ and OH-, H+ is moved into the lumen from the cells, and Cl- from the ecf is moved from cells into the lumen, and Co2 combines with OH- to from HCO3- and is moved into the bloodstream, the alakline tide

Question 22

What are the three phases of digestion?

Answer 22

The celphalic, the gastric and the intestinal phase of digestion

Question 23

What happens in the celphalic stage of digestion?

Answer 23

30% of the totalHCl is produced, parasympatheic stimuli from smelling chewing and swallowing, direct stimulation of the parietal cell by the vagus nerve, meaning stimulation of the G cells by the vagus nerve meaning the GRP is produced

Question 24

What happens in the gastric phase of digestion?

Answer 24

60% of HCl is produced, distension of the stomach stimualtes the vagus, stimulates the parietal and the g cells, presence of amino acids and peptides stimualte the g cells, food acts as a buffer increases the pH and therefore removes the inhibition on HCl production

Question 25

What happens in the intestinal phase of digestion?

Answer 25

10% of HCl production, the presence of chyme initially stimulates the gastrin secretion, but is soon overtaken by the inhibition of g cells, presence of lipids activates the enetrogastric reflux, adn therefore reduced the vagal stimulation, chyme stimulates CCk and secretin and therefore this helps to suppress secretion

Question 26

What are some of the features that protect the stomach from stomach acid?

Answer 26

Mucous and HCO3- are reasleased by the mucous cells and the neck cells and gastrin glands and help to create an alkaline layer, high turnover of epitehral cells, prostaglandins are used to help maintain the blood flow to the epithelial cells to supply them with nutrei t supply

Question 27

What are some of the forces that break the stomach defences?

Answer 27

Alchol dissolves the mucus layer, helicobacterpylori, NSAiDs as they stop the sytehsis of prostagladins

Question 28

What things can happen when the stomach defences aren’t working correctly?

Answer 28

Gastrtis, which can result in atriphy and dysplasia, ulceration commonly along the lesser curvature of the stomach, chromoc reflux due to dysfunction of the lower oesphageal spincther that can predispose a patient to metaplasia

Question 29

What do PPIs target and name one.

Answer 29

Omeprazole, targets the proton pumps in the parietal cells

Question 30

Name a H2 blocker and what do they target?

Answer 30

Cimitemine and ratinidome, target the H2 pump which normally is affected by histaimine that is produced by the enterochromaffin cells