Anatomy

Endoderm—epithelial, GI glands, (liver, gall badder, Pancreas)

Splanchnic Mesoderm—Intrinsic Muscle, Conn Tiss, Peritoneal Linings

Neural Crest—Enteric Nervous System

Coronal-Cuadal folding incorporates endodermal lining and splancnich mesoderm into embryo to for the Primitive Gut

• Pharyngeal Gut|Foregut|Midgut|Hindgut
• (Foregut, midgut, hindgut are considered as 3 abdominal division)

Buccopharyngeal membrane-primitive mouth –part of phyrengeal gut

Foregut – trachealbrochial diverticum (lung bud)

Midgut – connect to the yolk sac by Vitilline Duct. bring vitamins to embryo—becomes umbilical chord

Cloacal Membrane-primitive anus(closed) –part of hindgut

with an Unpaired artery from aorta

1. Celiac: supplies Foregut—Esophegus, stomach Duedonal Loop, spleen

2. Superior Mesenteric Artery: supplies Midgut—small & large intestines

3. Inferior Mesenteric artery: supplies Hind gut—Urogenital system, anus

Kidney—Renal Artery

Adrenal Medulla—Suprarenal Artery

Gonads—Gonadal Artery

Celiac Artery (first major branch of the abdominal aorta)

Superior Mesenteric artery

Inferior Mesenteric Artery

Parietal: lines abdominal cavity

• Visceral: reflected on to organs double fold also called mesentery
• - Mesentery: suspends organs from posterior abdominal wall (always posterior)
• - Omentum: loose support from one organ to another
• - Ligament: double fold of peritoneum from organ to organ, or from organ
• to abdominal wall

• S = Suprarenal glands (aka the adrenal glands)
• A = Aorta/IVC
• D = Duodenum (second and third segments [some also include the fourth segment] )
• P = Pancreas (tail is intraperitoneal)
• U= Ureters
• C= Colon (only the ascending and descending branches)***
• K = Kidneys
• E = Esophagus
• R = Rectum

• ***transverse
• colon is completely incased in visceral peritoneal to allow for free moving

-Esophagus, Stomach, Liver, Duodenum, Dorsal/Ventral Pancreatic Outgrowth, Gall bladder

- Hepatoduodenal ligament-connects liver and Deuodenum

- Gastohepatic Ligament- Stomach and liver

FYI Stomach turns 90 deegrees during development

Gastric: supplies the lesser curverature of the less side of stomach

Splenic: supplies the spleen

• Common Hepatic Artery: branches to supply the right side of stomach, liver,
• gall bladder, part of the pancreas
• - hepatic artery
• - proper hepatic artery
• - right gatric artery

Falciform is double layered lining that connect liver to the body wall

• --within falciform ligament is the ligamentum teres which is the reminence
• of the obliterated umbilical vein

The portion of the area that is smashed up against the diaphragm not covered by the peritonium

The bare area of the liver is clinically important because it represents a site where infection can spread from the abdominal cavity to the thoracic cavity

• Bi-carbonate into the duondenum in order to
• neutralize chyme

• In free margin of lesser omentum (hepatodudenal ligament)
• Place where vessels and bile duct lie

• Superior Mensentary Artery goes over the renal vein -- complication when SMA clamping renal vein during inflammation
• Pancrea sits on top (pancreatic cancer gets it)

from distal duodenum through 2/3 transverse colon:

• Small intestine--duodenum (10”), jejunum (8’), ileum
• (12’)

caecum(blind sack) and appendix,

Ascending colon

2/3 of transverse colon

duodenum

-Failure of Midgut to retract into abdomen

more rapid than developing abdomen



Herniates out of abdominal cavity

Rotation clockwise around the axis of superior mesenteric artery

Will eventualy retract into abdomen

Caudal limb subsequently retracts, undergoing further rotation

Large Intestine

distal 1/3 transverse colon

descending colon

sigmoid colon

superior 2/3 anal canal [inferior 1/3 anal canal ectoderm]

epithelium of bladder

most of urethra

thin strip of muscle that runs the length of the large intestine but not the entire length gives rise to the pouch formation (haustra)

• Haustra-small pouches caused by saculation which gives colon segmented
• appearance

• Inferior Mesenteric Artery supplies the distal 1/3 of transverse colon
• to anal canal
• Urorectal septum grows and divides hindgut
• -rectum and anal canal are dorsal
• -urogenital sinus is ventral

Uroectal septum divides the hindgut into front and back. The posterior parts become structures of the GI tract, and the anterior parts become parts of the urinary system. This is why parts of the bladder and urinary system are supplied by the inferior mesenteric artery.

Blood will drain into liver first before entering inferior vena cave

• does not want heart to receive toxins/
• nutrients

From small Intestine to Large Intestine

Can be innervated by Autonomic NS or on its own

• Ext: Autonomic (sympathetic and parasympathetic)
• Int: Enteric

• Sympathetic nerves have a general inhibitory action on digestion, inhibiting smooth muscle contraction and secretion.
• Splanchnic nerves (preganglionic), synapse in celiac ganglion surrounding celiac artery, and in ganglia surrounding superior and inferior mesenteric arteries.

Parasympathetic nerves have a general stimulatory action. Vagal nerves (preganglionic) synapse in myenteric and submucous plexus within gut wall to innervate through transverse colon. Sacral outflow of parasympathetics supplies distal organs.