GI VASCULAR SUPPLY & INNERVATION (anatomy) Flashcards
The digestive system within the abdomen consists of derivatives of the embryonic gut supplied by unpaired……….. branches of the abdominal aorta (See attached pic).
The caudal foregut is supplied by the…………………
ventral celiac trunk (celiac artery)
Midgut is supplied by the………………… artery.
superior mesenteric
Hindgut is supplied by the……………….. artery.
inferior mesenteric
The embryonic foregut forms what in an adult?
- Abdominal portion of the esophagus
- Stomach
- Duodenum, as far as its union with the common bile and pancreatic ducts (middle of descending part)
- Liver and gallbladder
- Pancreas
- Spleen, which is not part of the digestive tract but is closely related by position
What are the branches of the celiac trunk that supply derivatives of the embryonic caudal foregut?
- Left gastric artery
- Splenic artery
- Common hepatic artery
What does the left gastric artery supply?
the stomach and the lower esophagus
What does the splenic artery supply?
– Supplies the neck, body, and tail of the pancreas and the spleen
– Also sends branches to the stomach
The common hepatic artery branches into what arteries, and what do they supply?
– Gastroduodenal artery: supplies the stomach, head of the pancreas, and duodenum.
– Proper hepatic artery: supplies the liver and gallbladder; it also sends a branch to the stomach.
Duodenal ulcers usually occur in the……….. part of the duodenum.
superior
Posterior duodenal ulcers erode directly onto the…………………. artery or more commonly on posterior superior pancreaticoduodenalartery (a branch of……………..). This produces massive hemorrhage which can be fatal!!!
gastroduodenal
gastroduodenal
Anterior duodenal ulcers erode into what?
into the peritoneal cavity (peritonitis caused leads to adhesion of the greater omentum).
The embryonic midgutforms what in the adult?
- Duodenum (distal to its union with the bile and pancreatic ducts)
- Jejunum and ileum
- Cecum and appendix
- Ascending colon
- Transverse colon
Branches of the superior mesenteric artery supplying derivatives of the embryonic midgut are:
- Inferior pancreaticoduodenal artery
- Intestinal branches
- Middle colic artery
- Right colic artery
- Ileocolic artery
What do they each lead to?
- Inferior pancreaticoduodenal artery: to the head of the pancreas and the duodenum
- Intestinal branches: to the jejunum and ileum
- Middle colic artery: to the transverse colon
- Right colic artery: to the ascending colon
- Ileocolic artery: to the terminal ileum ,cecum, and ascending colon; it also gives off the Appendicular artery to the appendix!
* The Ileocolic artery leads to the terminal ileum ,cecum, and ascending colon. it also gives off the Appendicular artery to the appendix!
The embryonic hindgut forms what in the adult?
- Descending colon
- Sigmoid colon
- Rectum andanal canal
What are the branches of the inferior mesenteric artery that supply derivatives of the embryonic hindgut, and what do they supply?
- Left colic artery: the descending colon
- Sigmoid arteries: the sigmoid colon
- Superior rectal artery: the rectum and anal canal
Branches of the superior and inferior mesenteric arteries anastomose, forming a……………… artery, which runs parallel to the colon. This collateral circulation may prevent infarction of a segment of colon if one of the branches is obstructed or has to be ligated.
marginal
Venous drainage from the abdominal GI tract and spleen enters which vein for transport to the liver?
This is unlike blood from the rest of the body. Why?
hepatic portal vein
It does not pass directly toward the superior or inferior vena cava. One consequence is that cancer from the GI tract often metastasizes to the liver!
The hepatic portal vein is formed posterior to the neck of the pancreas by the union of what two veins?
- Splenic vein (the inferior mesenteric vein usually drains into the splenic vein)
- Superior mesenteric vein
Tributaries of the hepatic portal vein form connections (anastomose) with tributaries of the systemic venous system (venae cavae). These portacaval (portal-systemic) anastomoses may become abnormally dilated if there is resistance to portal blood flow (such as in cirrhosis), increasing pressure within the portal vein. This is called what?
portal hypertension
In portal hypertension, portacaval anastomoses that may enlarge include those found where?
- Lower esophagus (as esophageal varices)
- Anal canal (as hemorrhoids)
- Paraumbilical region (as varicose veins radiating outward from the umbilicus, aka caput medusae)
……………. may be the source of fatal hemorrhage in portal hypertension, and occurs secondary to cirrhosis of the liver.
Esophageal varices
In the condition known as……………….., the subcutaneous veins radiating from around the umbilicus dilate secondary to portal hypertension. The radiating veins reminded an early physician of the snakes on the head of Medusa of Greek mythology
caput medusae
The sympathetic nervous innervation of abdominal organs consists of……………. nerve fibers that reach prevertebral ganglia through splanchnic nerves, and…………….. nerve fibers from cell bodies in prevertebral ganglia that follow arteries to organs.
preganglionic
postganglionic
Prevertebral ganglia are located along the abdominal aorta at the origins of the:
- Celiac trunk – celiac ganglia
- Superior mesenteric artery – superior mesenteric ganglion
- Inferior mesenteric artery – inferior mesenteric ganglion
- Renal arteries (to the kidneys) – aorticorenal ganglia
Here is the picture:
Splanchnic nerves that carry preganglionic sympathetic nerve fibers to prevertebral ganglia are the Thoracic splanchnic nerves and Lumbar splanchnic nerves. The thoracic splanchnic nerves are:
* These werent bolded, but know the general idea at least.
–Greater splanchnic nerve (T5-9)
–Lesser splanchnic nerve (T10-11)
–Least splanchnic nerve (T12)
Thoracic splanchic (preganglionic) nerves generally supply what?
foregut (celiac trunk) and midgut (superior mesenteric artery) territory.
* Seen in red in the picture!
Lumbar (preganglionic) splanchnic nervessupply what?
hindgut (inferior mesenteric artery) territory
* Green on pic!
Since the autonomic nerve fibers to visceral organs follow the blood vessels, knowledge of the blood supply gives the source of preganglionic input! Ex:
- Celiac ganglia nerve fibers follow celiac trunk branches to foregut derivatives: stomach, proximal duodoenum, liver, gallbladder, pancreas; they also supply the spleen.
- Aorticorenalganglia fibers follow renal artery branches to the kidneys and adrenal glands.
- Superior mesenteric ganglia fibers follow superior mesenteric artery branches to midgut derivatives: distal duodenum, jejunum and ileum, ascending and transverse colon.
Here is the pic from the slide:
Here is a summary of Splanchnic Nerves picture:
Vagus nerve fibers enter the abdomen through the esophageal hiatus of the diaphragm as anterior and vagal trunks formed from the esophageal plexus. They supply……………….. parasympathetic input to ganglion cells located near or within the wall of the visceral structure!
preganglionic
Pelvic splanchnic nerves leave the sacral spinal cord through the……… rami of spinal nerves……… and send PREGANGLIONIC parasympathetic fibers to hindgut derivatives.
anterior
S2-4
Visceral afferent fibers, which accompany……………. nerves, carry pain from abdominal viscera to the spinal cord. Visceral pain is stimulated by tissue injury (ex: ischemia), sudden distention, or muscle spasms. Pain from viscera may be referred to other areas of the body that receive somatic innervation (ex: skin) from the same spinal cord segments.
sympathetic
Knowing that foregut derivatives (ex: the stomach) receive preganglionic sympathetic innervation from spinal cord segments T5-9 (greater splanchnic nerve), if a patient has referred pain to those dermatomes, it indicates which organs are most likely involved in the pathology causing the pain. Here is the pic from the slides:
Irritation of the………….. nerve from inflammation of the diaphragmatic pleura or peritoneum may cause referred pain to the…………. shoulder. The pain is referred to the shoulder because afferent fibers of the phrenic nerve (C3,4,5) enter the same spinal cord segments as the supraclavicular nerves (C3,4), which supply cutaneous innervation to the shoulder.
phrenic
ipsilateral
