Abdomen V - Stomach Flashcards
stomach
expanded part of the alimentary tract between the esophagus + small intestine
In most people, the shape of the stomach resembles___________?
What causes variations in the position of the stomach from person to person?
What causes variations in the position of the stomach in an individual?
normally = the letter J
person to person = body type
individual variation:
- diaphragmatic movements during respiration
- stomach’s contents
- position of the person.
An empty stomach is only slightly larger than the large intestine;
How much food can it hold when expanded?
How much can a newborn’s stomach hold?
2 - 3 L of food
newborn = up to 30 mL of milk
What are the functions & specializations of the stomach?
specialized for:
- accumulation of ingested food
- chemical + mechanical preparation of food for digestion
- passage of food into the duodenum
functions:
- enzymatic digestion
(food blender and reservoir)
The gastric juice gradually converts a mass of food into what?
Where is it passed to?
**chyme - **a semiliquid mixture
(passes quickly into duodenum)
What are the 4 parts of the stomach?
- cardia
- fundus
- body
- pyloric part (antrum + canal)
cardia
the part of the stomach surrounding the cardial orifice
fundus
- dilated superior part of the stomach that is related to the left dome of the diaphragm
- limited inferiorly by the horizontal plane of the cardial orifice
The superior part of the fundus usually reaches what level?
left 5th intercostal space
What is located between the esophagus and the fundus?
cardial notch
The fundus may be dilated by …?
gas
fluid
food
combination of these
body of stomach
major part of the stomach between the fundus and the pyloric antrum
pyloric part
- funnel-shaped outflow region of the stomach
- pyloric antrum= wide part; leads into pyloric canal = narrow part
The pylorus (distal, sphincteric region of the pyloric part) is a marked thickening of the circular layer of smooth muscle.
What does this control?
discharge of the stomach contents through the pyloric orifice into the duodenum
When does intermittent emptying of the stomach occur?
when intragastric pressure overcomes the resistance of the pylorus
What is the normal state of the stomach?
What is an exception to this?
tonically contracted so that the pyloric orifice is reduced
*except when emitting chyme*
What process passes the chyme through the pyloric canal + orifice into the small intestine for further mixing, digestion, and absorption?
When does this occur?
gastric peristalsis
- at irregular intervals
What are the 2 curvatures of the stomach?
lesser curvature
greater curvature
Lesser curvature
forms the shorter concave border of the stomach
Greater curvature
forms the longer convex border of the stomach
angular incisure (notch)
- sharp indentation approx. 2/3 the distance along lesser curvature
- indicates the junction of the body + pyloric part of the stomach
In a live patient, the interior of the stomach is covered by …?
What protection does this provide?
- a continuous mucous layer
- protects its surface from the gastric acid
gastric folds (or gastric rugae)
- contraction = gastric mucosa thrown into longitudinal ridges
- are most marked toward the pyloric part and along the greater curvature
- folds diminish and obliterate as the stomach is distended (fills)
A gastric canal (furrow) forms temporarily during swallowing between what structures?
How can it be observed?
- longitudinal gastric folds of the mucosa along the lesser curvature
- observed radiographically + endoscopically
Why does the gastric canal form?
What passes through this canal?
- because of the firm attachment of the gastric mucosa to the muscular layer
(no oblique layer at this site)
- Saliva + small quantities of masticated food and other fluids
(to the pyloric canal when the stomach is mostly empty)
What is the stomach covered by?
What area is the exception to this?
peritoneum
- except = where blood vessels run along its curvatures + in a small area posterior to the cardial orifice
The two layers of the lesser omentum extend around the stomach and leave its greater curvature as…?
as the greater omentum
Anteriorly, the stomach is related to what 3 structures?
diaphragm
left lobe of liver
anterior abdominal wall
Posteriorly, the stomach is related to what 2 structures?
The posterior surface of the stomach forms most of the …?
- omental bursa and the pancreas
- anterior wall of the omental bursa
From superior to inferior, the stomach bed is formed by what 6 structures?
left dome of diaphragm
spleen
left kidney + suprarenal gland,
splenic artery
pancreas
transverse mesocolon + colon