Stomach

Question 1

What is the stomach?

Answer 1

• a distensible organ which lies in the left hypochondrium, epigastric, and umbilical regions of the abdomen
• J-shaped when empty

Question 2

What is the function of the stomach?

Answer 2

• primarily digestive rather than absorptive
• stores and mixes food with gastric secretions, converting it to chyme
• capacity: 2-3L

Question 3

What are the parts of the stomach?

Answer 3

• cardia: where the esophagus joins the stomach (surrounds the cardial orifice)
• fundus of stomach: above the cardia
• body of stomach: between the fundus and pyloric part
• pyloric part: the most distal portion, adjacent to the duodenum

Question 4

What are the curvatures of the stomach?

Answer 4

• greater curvature: convex, left-facing, greater omentum attachment
• lesser curvature: concave, right-facing, lesser omentum attachment

Question 5

What are the notches of the stomach?

Answer 5

• cardial notch: between esophagus and fundus

- angular incisure: between body and pyloric part

Question 6

What are the walls of the stomach?

Answer 6

• anterior

- posterior

Question 7

What are the openings of the stomach?

Answer 7

• cardial orifice: between the esophagus and the stomach

- pyloric orifice: between the stomach and duodenum

Question 8

What are the subdivisions of the pyloric part?

Answer 8

• pyloric antrum: wide proximal part
• pyloric canal: narrow distal part
• pylorus: distal termination of the pyloric part which contains:
  + pyloric orifice: into duodenum
  + pyloric sphincter: a circular muscle layer which surrounds the pyloric orifice

Question 9

How is the pylorus marked externally?

Answer 9

by the pyloric constriction

Question 10

What are gastric folds (rugae)?

Answer 10

• longitudinal folds of mucous membrane, located within the cavity of the stomach
• give mucosa a corrugated appearance
• increase the surface area

Question 11

What is congenital hypertrophic pyloric stenosis?

Answer 11

• a tumor-like increase in the size of the pyloric sphincter, which reduces the size of the pyloric canal
• present at birth
• more common in males
• results in projectile vomiting
• requires surgical intervention early in infancy

Question 12

What is pylorospasm?

Answer 12

• spasmodic contraction of the pyloric sphincter
• sometimes present in infants
• food does not pass easily from the stomach to the duodenum
• the stomach becomes overly full, resulting in vomiting, which may be projectile
• subluxations of T5-T9 may play a role

Question 13

How can one distinguish between congenital hypertrophic pyloric stenosis and pylorospasm?

Answer 13

via barium-enhanced x-ray

Question 14

What is a gastric ulcer?

Answer 14

• a crater-like depression in the mucosa of the stomach
• the stomach secretes an alkaline mucus which is viscous and forms a barrier between the stomach acid and mucosa
• sometimes this protection is inadequate; gastric acid erodes the stomach mucosa, forming a gastric ulcer
• causal factors:
  1. excess acid secretion: often related to stress
  2. inadequate mucus secretion: usually related to the presence of bacteria (Helicobacter pylori), which erode the mucus barrier
• secretion of gastric acid by the parietal cells is controlled by the vagus nerve; subluxations of T5-T9 may play a role

Question 15

What is the location of the stomach in relation to other organs/structures?

Answer 15

• anterior to the lesser sac and the pancreas

- posterior to the diaphragm, the left lobe of the liver, and the anterior abdominal wall

Question 16

What is the blood supply of the stomach?

Answer 16

branches of the celiac trunk

Question 17

What is the innervation of the stomach?

Answer 17

• from the celiac plexus
• fibers originate from the following sources:
  1. sympathetic: greater splanchnic nerves (T5-T9)
  2. parasympathetic: vagus nerve