Stomach et

Question 1

Name the parts of the stomach

Answer 1

cardia, fundus, body, antrum, pylorus

Question 2

What are the anatomical surfaces of the stomach?

Answer 2

Greater curvature, lesser curvature, cardial notch (gastroesophageal junction), angular incisure

Question 3

What are the histological zones of the stomach?

Answer 3

Cardia- mucus secretion
Fundus and body- mucus and gastric juices secretion
Pylorus- mucus secreting and endocrine cells

Question 4

What is the lining of the stomach?

Answer 4

Simple Columnar Epithelium

Question 5

Describe the roles between somatostatin, acid secretion etc

Answer 5

Acetylcholine stimulates G cells to produce gastrin and parietal cells to produce acid. gastrin also stimulates the parietal cells to produce acid. gastrin stimulates ECL to release histamine. histamine via the H2 receptor increases acid secretion on the parietal cell, whilst inhibiting somatostatin production from D cells via the H3 receptor. somatostatin inhibits acid secretion and histamine secretion

Question 6

How do the oesophagus and stomach protect themselves from acid?

Answer 6

There is a thickening of smooth muscle at the gastro-oesophageal junction, known as the lower oesophageal sphincter. the stomach is lined with simple columnar epithelium from which mucous secretions full of bicarbonate provide protection from the acid

Question 7

what do the parietal and chief cells secrete?

Answer 7

parietal cells secrete HCL, whilst chief cells secrete pepsinogen which becomes pepsin in the presence of acid. pepsin aids in the breakdown of peptides.

Question 8

How are carbs digested?

Answer 8

carbs are digested by pancreatic enzymes in the duodenum. (e.g. alpha amylase) and by specific enzymes in the brush border

Question 9

how are fats digested?

Answer 9

pancreatic lipase degrades the fat lipids to mono chains and fatty acids. their presence promotes lipid emulsification. the emulsion is then coated by bile salts from bile. these micelles are then transported around the body in the bloodstream

Question 10

how are proteins digested?

Answer 10

by gastric pepsin and pancreatic endo/exo peptidases.

Question 11

what are the two sections of small intestinal motility?

Answer 11

segmentation- mixing of chyme by moving it back and forth

peristalsis- movement of chyme downstream.

Question 12

what is the role of the colon?

Answer 12

fluid and electrolyte absorption. the breakdown of carbs by bacteria in the colon produces 7% of the daily energy needs.

Question 13

how does pooping happen?

Answer 13

upon rectal distension, the internal sphincter is relaxed. when the external sphincter which is under voluntary control and puborectalis muscles are relaxed then faeces can pass.

Question 14

What is the cephalic phase?

Answer 14

Phase where vagus nerve stimulates parietal cells to produce acid upon sight, smell or thought of food.

Question 15

What is the gastric phase?

Answer 15

where the food in the stomach activates G cells in the antrum and pylorus of the stomach to secrete gastrin which stimulates ECL cells and parietal cells to produce histamine and more acid respectively

Question 16

how is acid regulated?

Answer 16

high levels of hydrogen ions signal D cells to produce somatostatin, inhibiting G cells from releasing more gastrin

Question 17

What cells in the stomach produce what?

Answer 17

G cell- gastrin
D cell- somatostatin
ECL cell- histamine
parietal cell- HCL
chief cell- pepsinogen
mucus cells- mucus

Question 18

What are the nine quadrants of the abdomen?

Answer 18

Right, left hypochondrium
Right, left groin
epigastric region
umbilical region
right, left flank
pubic region

Question 19

What are the four layers throughout the GI tract?

Answer 19

Mucosa- lined with epithelium closest to lumen, then laminae propria a type of connective tissue and then muscularis mucosae which provides the contractions

Submucosa- contains blood vessels, nerves and lymphatics

Muscularis propria- smooth muscle layer, two layers of inner circular (IC) and outer longitudinal (OL)

Serosa- loose connective tissue providing support

Question 20

What level does the oesophagus (OP) enter the diaphragm and where?

Answer 20

through the OP hiatus around the tenth vertebra. the hiatus is made by the right crus muscle

Question 21

what are the linings of the stomach and op?

Answer 21

stratified squamous in the op and simple columnar in the stomach

Question 22

Describe the blood supply to the stomach

Answer 22

the stomach is supplied by three branches of the celiac trunk, common hepatic/ left gastric and splenic arteries.

the left and right gastric run along the lesser curvature
the short gastric supply the fundus
left and right gastro-omental arteries run along the greater curvature, the left branches from the splenic and the right from the gastroduodenal

Question 23

What are the greater and lesser sacs and how do they communicate?

Answer 23

potential space between the peritoneums of the abdomen. they communicate through the omental foramen.