Chapter 23
The Digestive System
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23
lef quadrant oF the peritoneal cavity, nearly hidden by the liver
and diaphragm. Tough relatively fixed at both ends, the stom-
ach is quite movable in between. It tends to lie high and run hori-
zontally in short, stout people (a steer-horn stomach) and is ofen
elongated vertically in tall, thin people (a J-shaped stomach).
Gross Anatomy
Te adult stomach varies From 15 to 25 cm (6 to 10 inches)
long, but its diameter and volume depend on how much Food
it contains. An empty stomach has a volume oF about 50 ml
Cardia
Esophagus
Liver
(cut)
Lesser
curvature
Pyloric sphincter
(valve) at pylorus
Pyloric
canal
Pyloric
antrum
Rugae of
mucosa
Body
Body
Lumen
Serosa
Fundus
Fundus
Spleen
Lesser
curvature
Greater
curvature
Greater
curvature
Muscularis
externa
(a)
(b)
Duodenum
• Longitudinal la
yer
• Cir
cular layer
• Ob
lique layer
Figure 23.14
Anatomy of the stomach.
(a)
Gross internal anatomy (frontal section).
(b)
Photograph of external aspect of stomach. (For a related image, see
A Brief Atlas of the
Human Body
, Figure 69a.)
and a cross-sectional diameter only slightly larger than the large
intestine, but when it is really distended it can hold about 4 L
(1 gallon) oF Food and may extend nearly to the pelvis! When
empty, the stomach collapses inward, throwing its mucosa (and
submucosa) into large, longitudinal Folds called
rugae
(roo
9
ge;
ruga
5
wrinkle, Fold).
Figure 23.14a
shows the major regions oF the stomach. Te
small
cardial part
, or
cardia
(“near the heart”), surrounds the
cardial orifice through which Food enters the stomach From
the esophagus. Te
fundus
is the stomach’s dome-shaped part,
tucked beneath the diaphragm, that bulges superolaterally to
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