Abdominal organs & blood supply

18 March 2010

Esophagus

· The esophagus is properly a structure of the neck and thorax.

– Muscular tube connecting pharynx to stomach

– Mucosa in folds to allow for expansion

– Muscle fibers in both longitudinal and circular orientations

– Mixture of skeletal & smooth muscle

§ More skeletal superiorly, and smooth inferiorly

– Ends at esophageal hiatus at diaphragm

Netter, 2003 pls. 229-230, 233; Netter, 2006 pls. 233-234, 237

Vagal Trunks on Esophagus

· The vagus runs along the surface of the esophagus bringing parasympathetic innervation.

· Due to gut rotation in development, the left vagus becomes anterior and the right becomes posterior.

· They continue into the abdomen to supply parasympathetic innervation there.

Netter, 2003 pl. 236; Netter, 2006 pl. 240

Gastroesophageal Junction

· Longitudinal muscle of Esophagus attached to Diaphragm by phrenoesophageal ligaments.

· Cardia of stomach

Netter, 2003 pl. 232; Netter, 2006 pl. 236

Veins of the Mediastinum

L. & R. Brachiocephalic vv.

Azygos

Hemiazygos

Submucosal esophageal venous plexus

Branches of gastric veins form a venous bypass around the liver

Netter, 2003 pl. 234; Netter, 2006 pl. 238

Blood Supply to Abdominal Organs

· Abdominal arteries are either paired or unpaired branches of the aorta

· Unpaired branches supply digestive structures and reflect development

· Celiac

– Artery of foregut

– Stomach, duodenum-1

· Superior mesenteric

– Artery of midgut

– Duodenum-2, -3, -4, jejunum, ileum, ascending colon

· Inferior mesenteric

– Artery of hindgut

– Transverse, descending & sigmoid colons, rectum

Netter, 2003 pls. 291-292; Netter, 2006 pls. 300-302

Celiac Trunk

· Splenic a.

· Common hepatic a.

· L. Gastric a.

· Proper hepatic a.

· R. Gastric a.

· Gastroduodenal a.

· Gastroepiploic a.

· Sup. Pancreaticoduodenal a.

· Gastroepiploic a.

Netter, 2003 pl. 290, 291; Netter, 2006 pl. 300, 301

Pancreas

Head, body, tail

Head associated with 2nd part of duodenum, and shares its blood supply. The body & tail of the pancreas are supplied by the splenic a.

Netter, 2003 pl. 291; Netter, 2006 pl. 301

Parts of Stomach

· Fundus

· Cardia

· Body

· Pyloric antrum

· Pyloric canal

· Pylorus

· Duodenum (1st part)

· Rugae

· Pyloric canal

· Pylorus

Netter, 2003 pl. 267, 268; Netter, 2006 pl. 275, 276

Abdominal Organs & their Mesenteries

· Most abdominal organs are completely enclosed in sheets of visceral peritoneum.

· The peritoneum is attached to the body wall, gives access for nervous and blood supply

allows organ to move.

– Peritoneal

· Some organs are attached directly to the posterior abdominal wall.

· They are covered anteriorly by a sheet of parietal peritoneum, but they are not free to

move.

· Blood and nerve supply from vessels running under the peritoneal surface of the abdominal

wall

– Retroperitoneal

· Retroperitoneal organs

· Some retroperitoneal organs developed posterior to the parietal peritoneum and were never

peritoneal

– Primarily retroperitoneal

Other organs were originally peritoneal and in development became retroperitoneal

– Secondarily retroperitoneal

Examples of Retroperitoneal Organs

· Primarily retroperitoneal organs

– Kidney

– Suprarenal glands

– Ureters

– Major blood vessels and associated nerves

· Secondarily retroperitoneal organs

– Duodenum, parts 2-4

– Pancreas

– Ascending & descending colon

Superior Mesentaric Artery & Associated Viscera

Blood supply to midgut.

· Inf. pancreaticoduodenal aa.

· Middle colic a.

· Right colic a.

· Iliocolic a.

· Jejunal & ileal aa.

· Arteriae rectae

Netter, 2003 pl. 295; Netter, 2006 pl. 306

Duodenum

Part 1

Part 2

Part 3

Part 4

Pancreas

The duodenum becomes retroperitoneal when the intestine loops during development.

Superior mesenteric a. runs over duodenum

Netter, 2003 pl. 270; Netter, 2006 pl. 278

Greater omentum

(reflected superiorly)

· Transverse colon

· Transverse mesocolon

· Jejunum

· Ileum

· Cecum

· Ascending colon

Netter, 2003 pl. 261; Netter, 2006 pl. 269

Colon & its blood supply

· Ascending colon

– right colic a.

· Transverse colon

Middle colic a.

· Descending colon

· Inferior mesenteric a.

– sigmoid aa.

– superior Rectal a.

· Taenia coli

Netter, 2003 pl. 296; Netter, 2006 pl. 307

Aortic Ganglia

Celiac ganglion

Superior mesenteric g.

Inferior mesenteric g.

Superior Hypogastric plexus

Sympathetic innervation to the abdominal viscera synapses here.

Netter, 2003 pl. 308; Netter, 2006 pl. 318

Hepatic Portal System

Hepatic portal v.

Gastric v.

Splenic v.

Sup. Mesenteric v.

Inf. Mesenteric v.

Blood draining from intestines passes first to the liver.

Netter, 2003 pl. 302; Netter, 2006 pl. 312