Lower Abdomen Flashcards
What is the entrance to the stomach from the esophagus?
Cardiac oriface
What is the exit from the stomach to the duodenum?
The pyloric sphincter
What is the primary function of the stomach?
Enzymatic digestion
Describe the mobility of the duodenum?
Fixed and relatively immobile
Describe the mobility of the jejunum and ilium?
Tethered but very mobile
What is the combined length of the three parts of the small intestine?
20 ft
What are the permanent folds within the small intestine called?
Plicae circularis
Describe the concentration of the plicae circularis in the proximal and distal portions of the small intestine?
Become fewer or more diffuse as we move distally
What is the ileocecal junction?
Where the ilium empties into the cecum
What allows the small intestine to be more compact and fit into the abdomen?
Tonic contraction
What part of the duodenum is intra versus retraperitoneal?
The duodenal cap is retroperitoneal and the rest of the duodenum is intraperitoneal
What vertebral level is the superior part of the duodenum?
L1
What vertebral level is the descending part of the duodenum?
L2-L3
What vertebral level is the inferior part of the duodenum?
L3
What vertebral level is the ascending part of the duodenum?
L3-L2
As we move proximal to distal in the jejunum and ilium what happens to the vasa recta?
They decrease in length
As we move proximal to distal in the jejunum and ilium what happens to the plica circularis?
They decrease in number
As we move proximal to distal in the jejunum and ilium what happens to the arterial arcades?
They increase in length and number
As we move proximal to distal in the jejunum and ilium what happens to fat accumulation?
It increases
As we move proximal to distal in the jejunum and ilium what happens regarding lymphatics?
They increase
If the jejunum and ilium section of the small intestine were divided into fifths, how long is each component?
Jejunum is proximal 2/5 and ilium is distal 3/5
Using the quadrant abdominal division, where are the jejunum and ilium located?
Jejunum is upper left and ilium is lower right
What is Meckel’s (ileal) diverticulum?
Remnant of the embryonic yolk sac
Where would Meckel’s diverticulum be found?
1 m proximal to ilieocecal valve
How many parts are there in the large intestine?
5 segments and 2 flexures
What are the 5 segments of the large intestine?
Cecum, ascending, transverse, descending, sigmoid
What are the two flexures of the large intestine called?
Right colic (hepatic), and left colic (splenic) flexures
How is the left colic flexure attached?
This part of the large intestine is attached to the diaphragm via splenocolic flexure
What are the right and left paracolic gutters?
These are depressions that are lateral to the ascending and descending segments of the large intestine, through which materials pass from one region of the peritoneal cavity to another
What are the teniae coli?
These are 3 smooth muscle bands paralleling the length of the colon
What are the haustra coli?
These are outpouchings that are created by the teniae coli
What are the epiploic appendages?
These are fat tags found along the colon (blobs of fat)
The left branch of the middle colic artery anastomoses with what artery?
Inferior mesenteric artery
How many arteries does the SMA send to the small intestine?
15 - 18
How distal of the intestine does the SMA supply?
Up to the proximal 2/3 of the transverse colon
Where is the IMA located on the aorta?
5 cm superior to the aortic bifurcation
What part of the intestine does the IMA supply?
Starts at the distal 1/3 of the transverse colon and supplies to rectum
What are the three main branches of the IMA?
Left colic, sigmoid (4), and superior rectal
Where do the middle colic and left colic arteries anastomose?
At the marginal arteries
Why do anastomoses exist between colic branches?
For collateral circulation, this forms consistent vascular arc around the colon
The renal arteries are branches of what artery?
Lateral branches of abdominal aorta, lateral to SMA
The renal arteries send branches off to what two other structures?
Adrenal glands and ureters
What artery do the ovarian and the testicular arteries come from?
The gonadal artery which is a lateral branch of the aorta (inferior to the renal artery
Explain the path ovarian arteries must cross to supply the ovaries.
They will cross over the ureters and the iliac vessels, and descend into pelvis to supply the ovaries
Explain the path testicular arteries must cross to supply the testes.
Cross over ureters and enters inguinal canal, then descends into scrotum to supply the testes
The gonadal arteries will descend along what muscle?
The psoas muscle
Where does the inferior vena cava start?
Begins at the L5 level at the union of common iliac veins
What areas of the body does the IVC drain?
LL, most of the back, abdominal wall, and abdominal pelvic viscera, and nutrient rich blood from the portal venous system.
Where is the portal vein started?
By the union of the splenic and the superior mesenteric veins
The portal vein has venous return from what viscera?
Spleen, gallbladder, pancreas, abdominal gastrointestinal tract
What are the 4 portal-caval anastomoses?
Gastric vv. and esophageal vv.,
paraumbilical vv. and epigastric vv.,
superior rectal vv. and middle/inferior rectal vv.,
colic vv. and retroperitoneal vv.
Of the gastric and esophageal vv, which is portal and which is caval?
Gastric vv. is portal
esophageal vv. is caval
Of the paraumbilical and epigastric vv. which is portal and which is caval?
paraumbilical vv. is portal
epigastric vv. is caval
Of the superior rectal and middle/inferior rectal vv. which is portal and which is caval?
Superior rectal vv. is portal
middle/inferior rectal vv. is caval
Of the colic vv. and retroperitoneal vv. which is portal and which is caval?
Colic vv. is portal
retroperitoneal vv. is caval
The portal venous system is missing what structure that other venous systems have?
Valves, the portal system relies solely on pressure
Dilated esophageal vv. produce what?
esophageal varices
Dilated epigastric vv. produce what?
caput medusae
Dilated inferior/middle rectal vv. produces what?
hemorrhoids
The sympathetic nervous system has what other name?
Thoracolumbar (T1-L2)
Where are the parasympathetic nerves located?
Cranial and S2-S4
Innervation to the viscera of the abdomen is via what?
Autonomic n. plexus
What vertebral levels innervates the entire abdomen?
T5 - L2
What is cranial nerve ten?
Vagus nerve
Preganglionic splanchnic nn synapse where?
In collateral ganglia
Postganglionic fibers leave collateral ganglia to reach what?
Effector organs
Post synaptic fibers travel on all what?
Main arterial branches
T10 - T11 are sympathetic chain nerve exceptions, where do they synapse?
At SMA collateral ganglion
T12 is a sympathetic chain nerve exception, where does this nerve synapse?
Renal or para-aortic
Preganglionic nerves from CN X travel on what?
Upper arterial branches (celiac trunk, SMA, renal aa., and all their branches)
Preganglionic nerves from S2-S4 travel on what?
Lower arterial branches (IMA and branches)
Where are the cell bodies in the parasympathetic nerves of the abdomen?
In the walls of the organs that they innvervate
What are the four major autonomic ganglia and their associated plexus?
Celiac ganglion, superior mesenteric ganglion, aorticorenal ganglion, inferior mesenteric ganglion
Postganglionic and what term are interchangeable?
Postsynaptic
