intra-abdominal portion of esophagus

stomach

upper part of duodenum

liver

gallbladder

pancreas

left gastric artery

splenic artery

common hepatic artery

blood will be diverted to middle colic artery (a branch of the superior mesenteric) which anastomoses with the left colic artery (a branch of the inferior mesenteric artery)

blood will also be diverted to marginal artery

superior mesenteric artery (branches off anterior portion of abd aorta)

renal arteries (branch off laterally from abd aorta)

supplying the right and left kidneys

lower part of duodenum

jejunum

ileum

cecum

appendix

ascending colon

prosimal 2/3 of transverse colon

gonadal arteries

vertebral level and supply what

L2

testest or ovaries

distal one third of the transverse colon

descending colon

sigmoid colon

upper portion of rectum

right and left common iliac arteries

vertebral level L4/L5

S2,3,4 (-> run as pelvic splanchnic nerves -> inferior hypogastric plexus -> visceral organs)

(innervation starts distal to the splenic flexure of the transverse colon)

AAA most commonly seen in:

(pt type and vertebral level)

seen in atherosclerotic eldery males

below L1 vertebral level -> below the renal and superior mesenteric arteries

below renal arteries in left posterolateral wall (into retroperitoneal space)

1st step -> immediate compression of aorta against vertebral bodies above celiac truck (T12)

left renal vein

(because most common site of a ruptured AAA is below the renal arteries in the left posterolateral wall, retroperitoneally)

AAA clinical findings

(w/o and w/rupture)

central abd pain, sudden and severe onset -> may radiate to the back

pulsatile tender abd mass

if rupture occurs -> hypotension and delirium

ischemic colitis -> due to ligation of the inferior mesenteric artery (which supplies the hindgut viscera)

spinal cord ischemia -> due to ligation of the great anterior segmental medullary artery (of Adamkiewicz) (artery coming from a poster intercostal artery or a lumbar artery that fuses with the anterior spinal artery

anterior spinal artery syndrome

and clinical symptoms

caused by the ligation of the great anterior segmental medullary (of Adamkeiwics) artery during resection of an AAA

clinical symptoms -> paraplegia, impotence, incontinence, loss of pain and temp (spinothalamic/anterolateral system tract), but vibration and proprioception sensation  intact

elderly pts with a hx of heart disease taking digoxin

digoxin -> potent splanchnic vasoconstrictor

severe abd pain out of proportion to physical findings

no evidence of peritonitis

gradual occlusion most commonly seen in

(pt type and location)

and may result in

most commonly seen in atherosclerotic pt at the bifurcation of the abdominal aorta

may result in claudication -> pain in the legs when walking; and impotence -> because of lack of blood to the internal iliac arteries

right ascending lumbar vein and the right subcostal vein

(the right lumbar veins flow into the right ascending vein)

azygos veins communicates with:

(what other veins)

(lower end of azygos communicates with) the IVC

the right posterior intercostal veins

the external and internal vertebral venous plexuses

**route of metastasis -> interconstal veins to cranial dural sinuses (via the vertebral venous plexuses)**

hemiaygos vein communicates with:

(what other veins)

union of the left ascending lumbar vein and the left subcostal vein

(the left lumbar veins flow into the left asending lumbar vein)

IVC drains all blood from below the diaphragm (even portal blood from the GI tract after it percolates through the liver)

and drains into the right atrium

IVC ligation above the kidneys (suprarenal) -> 100% mortality rate

IVC ligation below the kidneys (infrarenal) -> 50% mortality

right gonadal vein drains directly into the IVC

left gonadal vein drains into the left renal artery which then drains into the IVC

important in females

may indicate thrombosis of the right ovarian vein -> constricts the ureter (since the right ovarian vein crosses the ureter to drain into the IVC)

important in males

may indicate occlusion of the left testicular vein and/or left renal vein dur to a malignant tumor of the kidney

(varicocele -> abnormal enlargement of blood vessel)

these exist in case the IVC is blocked via a laignant retroperitoneal tumor or a large blood clot (thrombus)

azygos -> SVC -> right atrium

lumbar veins -> external and internal vertebral venous plexuses -> cranial dural sinuses -> internal jugular vein -> right atrium

capillaries of GI tract -> portal vein -> hepatic sinusoids -> hepatic vein (capillary bed where portal triad flows to and from, hepatic artery, portal vein branch, and a bile duct)

**portal vein comes INTO liver, hepatic vein GOES OUT of liver**

portal vein formed by the union of the splenic vein and superior mesenteric vein

inferior mesenteric vein usually ends with its fusion with the splenic vein (before the splenic artery joins with the superior mesenteric vein)

the portal vein is formed posterior to the neck of the pancreas

the superior mesenteric and splenic veins are both posterior to the pancreas as well

left gastric vein <--> esophageal vein

paraumbilical vein <--> superficial and inferior epigastric veins

superior rectal vein <--> middle and inferior veins

esophagus

umbilicus

rectum

vomiting copious amounts of blood, enlarged abdomen due to ascites fluid, splenomegaly

esophageal varices

caput medusa

anorectal varices

right hypochondriac, epigastric, left hypochondriac

right lumbar, umbilical, left lumbar

right inguinal, hypogastric, left inguinal

peracentesis

what are the two approaches (describe)

process done to remove/withdraw excess peritoneal fluid

midline approach: skin -> superficial fascia (camper and scarpa) -> linea alba -> transversalis fascia -> extraperitoneal fat -> peritoneum

flank approach: skin -> superficial fascia (camper and scarpa) -> external oblique -> internal oblique -> transversus abdominus -> transversalis fascia -> extranperitoneal fat -> parietal peritoneum

inguinal ligament

(formed by what, and attachments)

formed by the medial fibers of the inguinal ligament that run posteriorly to attach to the pecten pubis.

(inguinal ligament also attached to pubic tubercle as well)

begins at the deep inguinal ring and ends at the superficial inguinal ring

transmits the spermatic cord in males and the round ligament of the uterus in females

mass in inguinal region

protrudes on straining and disappears at rest (easily reducable)

constipation

prostate enlargement

felt with tip of finger

tender painful mass in inguinal region that continues into scrotum

felt with tip of finger

will metastasize to deep lumbar nodes

(bc of the embryologic development of the testes within the abdominal cavity and subsequent descent into the scrotum)

extravasated urine

found where

due to a saddle injury

found within the superficial perineal space located between the colles fascia and dartos muscle (converted from camper and scarpa superficial fascia) and the external spermatic fascia (converted from external oblique muscle)

cut through the following: skin -> colles fascia and dartos muscle -> external spermatic fascia -> cremasteric fascia and muscle -> internal spermatic fascia -> extraperitoneal fat

tunica vaginalis is not cut because it is found only on the anterior aspect of the testes

the conversions from the layers of the abdominal wall to the coverings of the testes and spermatic cord

(starting with outermost of abdominal wall)

skin -> remains as skin (ha, duh!)

superficial fascia (camper and scarpa) -> collel fascia and dartos muscle

superficial  perineal space

external oblique muscle -> external spermatic fascia

internal oblique muscle -> cremasteric fascia and muscle

transversus abdominus muscle -> doesn't continue into scrotal area

transversalis fascia -> internal spermatic fascia

extraperitoneal fat -> remains extraperitoneal fat

parietal peritoneum -> tunica vaginalis (found only on anterior aspect of testes)

potential space between the visceral and parietal peritonuem

divided into the lesser and greater peritoneal sacs

lesser peritoneal sac

formed by and boundaries

omental bursa

forms dues to 90 degree clockwise rotation of stomach during embryologic development

boundaries:

anterior -> liver, stomach, lesser omentum

posterior -> diaphragm

right side -> liver

left side -> gastroslepin and slenorenal ligaments

communicates with greater sac via omental foramen

remainder of peritoneal cavity

extends from diaphragm to the pelvis

contains numerous pouches, recesses, and paracolic gutters through which peritoneal fluid circulates

communicates with the lesser sac via the omental foramen

paracolic gutters

normal flow of peritoneal fluid

channels that run along the ascending and descending colon

peritoneal fluid normally flows upward through the gutters to the subphrenic recess

fluid enters subphrenic recess and then enters lymphatics associated with the diaphragm

when sitting/standing:

excess fluid flows downward through paracolic gutters to: rectovesical pouch in males or rectouterine pouch in females

supine position:

excess fluid flows upward through paracolic gutters to subphrenic recess and the hepatorenal recess

pt may complain of referred shoulder pain due to irritation of the phrenic nerve (C3,4,5 nerve roots)

reces is the lowest part of the peritoneal cavity when pt is in supine position

therefore, along with subphrenic recess, these two recesses are where excess peritoneal fluid pools

lesser omentum

consists of

fold of peritoneum that extends from the porta hepatis of the liver to the lesser curvature of the stomach

consists of: hepatoduodenal ligament and hepatogastric ligament

portal triad

composed of what and found in what structure

found in the free margin of the hepatoduodenal ligament of the lesser omentum

composed of:

portal vein (lying posterior)

proper hepatic artery (from common hepatic artery of celiac trunk) (lying anterior and to the left)

common bile duct (lying anterior and to the right)

stomach

first 2cm of superior part of duodenum (duodenal cap)

jejunum

ileum

cecum

appendix

transverse colon

sigmoid colon

liver

gallbladder

tail of pancreas

spleen

distal 3m of superior part of duodenum

descending part of duodenum

horizontal part of duodenum

ascending part of duodenum (until very end connecting to jejunum)

ascending colon

descending colon

rectum

head, neck, body of pancreas

kidneys

ureters

suprarenal glands

abdominal aortaand IVC

greater omentum

consists of

fold of peritoneum that hangs down from the greater curvature of the stomach

likes to adhere to areas of inflammation, being problematic

gastrocolic ligament -> connection to transverse colon

gastrosplenic ligament -> connection to the spleen

gastrophrenic ligament -> connection to thoracic diaphragm

caused by enlarged visceral organ or by escape of fluid from a visceral organ

causes sharp localized pain over the affected/inflammed area

rebound tenderness and gaurding of inflammed site

inflammation and infection of the peritonuem

commonly caused by: ruptured appendix, penetrating abdominal wound, perforated ulcer, poor sterile technique during surgery.

treat by rinsing peritoneal cavity with large amounts of sterile saline and antibiotics administration

occur after abdominal surgery

scar tissue forms and limits the normal movement of the viscera

tethering may cause chronic pain or emergency complications -> volvulus (twisting of intestines)

esophagus begins and ends where

vertebral level

begins at crocoid cartilate -> C6

ends at gastroesophageal junction

pierces diaphragm through esophageal hiatus

upper 5% -> skeletal muscle

middle 45% -> skeletal and smooth muscle, interwoven

distal 50% -> smooth muscle

4 segments:

cervical segment

upper thoracic segment

midthoracic segment

lower thoracic segment

junction of pharynx and esophagus ( cricoid origin)

aortic arch

tracheal bifurcation (vertebral level T4) -> where left main bronchus crosses esophagus

left atrium

esophageal hiatus

upper esophageal sphincter

muscle type and separates what structures

made of skeletal muscle

separates pharynx from the esophagus

upper esophageal sphincter

composed of what muscles

opening muscles:

thyrohyoid and geniohyoid muscles

closing muscles:

inferior pharyngeal constrictor and cricopharyngeus (main player)

lower esophageal sphincter

muscle type and separates what structures

function

smooth mucsle that separates esophagus from the stomach

prevents gastroesophageal reflux

inferior thyroid arteries -> give off ascending and descending branches that anatomose w/each other across the midline

subclavian artery -> thyrocervical trunk -> inferior thyroid artery -> esophageal branches

from four to five branches form the descending thoracic aorta

thoracic/descending aorta -> esophageal branches

from left gastric artery

abdominal aorta -> celiac trunk -> left gastric artery -> esophageal branches

to the inferior thyroid veins

esophageal branches -> inferior thyroid veins -> brachiocephalic veins -> SVC

inferior thyroid arteries come off of subclavian arteries (lateral to common carotid)

inferior thyroid veins drain into brachiocephalic veins (medial to internal jugular vein)

to an esophageal plexus of veins

esophageal venous plexus -> azygos (and hemiazygos) veins -> SVC

to left gastric vein

esophageal venous branches -> left gastric vein -> portal vein -> hepatic sinusoids -> central veins -> hepatic veins -> IVC

modulates enteric nervous system of esophagus

pregang cell bodies -> dorsal motor nucleus of vagus nerve; nucelus ambiguus

pregang axons -> run in CN X -> enter; CN X (recurrent laryngeal) -> both enter esophageal plexus

postgang cell bodies -> in enteric nerv. systm., some are traditional postgang parasymp which release ACh

postgang axons -> terminate on mucosal glands, submucosal glands, and smooth muscle; closing muscles of UES and esophageal skeletal muscle

nerves associated with dorsal nucleus -> innervate mucosal glands, submucosal glands, and smooth muscles

nerves associated with nucelus ambiguus -> innervate closing muscles of UES (inferior pharyngeal constrictor and cricopharyngeus muscle) and the esophageal skeletal muscle

modulated enteric nervous system

pregang cell bodies -> intermediolateral cell columns of T5-9

pregang axons -> form greater splanchnic nerve

postgang cell bodies -> diffuse ganglia along esophagus and celiac ganglion (part of prevertebral ganglia)

postgang axons -> synapse in complex circuitry of enteric nervous system

can cause enlargement of mediastinal lymph nodes which may indent the esophagus

(mediastinal lymph nodes -> posterior to esophagus, running along lateral sides of vertebral column)

can be observed radiologically during a barium swallow

malignant tumors of esophagus

most commonly found where and metastasize where

most commonly occur in lower one third of esophagus

mestastasize below the diaphragm to the celiac lymph nodes (found around the celiac trunk of the abd aorta)

forceful vomiting

commonly seen in, may cause what

clinical findings

commonly seen in alcoholism, bulimia, and pregnancy

may tear posterior wall of esophagus

clinical findings:

severe retrosternal pain after vomiting, extravasated contrast medium

mallory-weiss tears -> involve only the mucosal and submucosal layers

boerhaave syndrome -> involve all layers of the esophagus (circular and longitudinal muscle layers included)

sliding hiatal hernia

and clinical findings

stomach along with gastroesophageal junction herniate through diaphragm into thorax

clinical findings:

deep burning retrosternal pain and refulx of gastric contents into mouth, and accentuated in supine position

paraesophageal hiatal hernia

and clinical findings

only the stomach herniates through diaphragm into thorax

clinical findings:

no reflux of gastric contents

strangulation or obstruction can occur

failure of LES to relax during swallowing, probably due to lack of myenteric plexus

clinical findings:

 progressive dysphasia (difficulty swallowing)

barium swallow shows dilated esophagus above LES and distal stenosis at the LES

may lead to achalasia

caused by trypanosoma cruzi

caused by LES dysfunction that allows gastric acid reflux into lower esophagus

clinical findings:

substernal pain and heartburn, which may worsen with bending or lying down

autoimmune disorder

may be a systemic cause of esophageal reflux

strictures: narrowing

caustic strictures -> caused by ingestion of caustic agents (drain openers, oven cleaners)

other strictures -> caused by recurrent mucosal destruction due to gastric acid reflux, most often occur at gastroesophageal junction

dilation of subepithelial and submucosal venous plexuses that drain into the left gastric (coronary) vein

left gastric vein drains into portal vein from the distal esophagus and proximal stomach

caused by portal hypertension due to cirrhosis of the liver

simple columnar epithelium

distal 2cm of esophagus also has this same lining

the replacement of the esophageal stratified squamous epithelium with metaplastic "intestinalized" simple columnar epithelium (with Goblet cells) extending atleast 3cm into the esophagus (normally extends only 2cm)

all lower esophageal adenocarcinomas occur as a sequelae

cardia -> near gastroesophageal junction

fundus -> above the gastroesophageal junction

body -> between the fundus and antrum (part of pyloris)

pyloris -> the distal part of the stomach; pyloric antrum and pyloric canal

opening between the stomach and the first part of the duodenum

surrounded by the pyloric sphincter

pyloric sphincter -> well defined muscular sphincter that controls movement of food out of the stomach and prevents reflux of duodenal contents back into the stomach

arterial supply of the stomach

(names only)

right and left gastric arteries

right and left gastroepiploic/ gastro-omental arteries

short gastric arteries

right and left gastric arteries

supply what and from where

supply the lesser curvature of the stomach

right gastric: abdominal aorta -> celiac trunk -> common hepatic artery -> right gastric artery

left gastric: abdominal aorta -> celiac trunk -> left gastric artery

right and left gastroepiploic arteries

supply what and from where

supply the greater curavture of the stomach

right gastro-omental: abd aorta -> celiac trunk -> common hepatic artery -> gastroduodenal artery -> right gastro-omental artery

left gastro-omental: abd aorta -> celiac trunk -> splenic artery -> left gastro-omental artery

short gastric arteries

supply what and from where

supply the fundus of the stomach

abd aorta -> celiac trunk -> splenic artery -> short gastric arteries

gastroduodenal artery branches into what arteries

found between what structures

gastroduodenal comes off of common hepatic artery and terminates as branching into right gastro-omental/ gastroepiploic artery and anterior superior pancreaticoduodenal arteries

found between pancreas (posterior) and 1st part of duodenum (anterior)

venous drainage of the stomach

(names only)

right and left gastric veins

right and left gastroepiploic/ gastro-omental veins

short gastric veins

right gastroepiploic (from greater curvature) -> superior mesenteric artery -> portal vein -> hepatic sinusoids -> central veins -> hepatic veins -> IVC

left gastroepipolic (from greater curvature) -> splenic vein -> portal vein -> hepatic sinusoids -> central veins -> hepatic veins -> IVC

short gastric veins (from fundus) -> splenic vein -> portal vein -> hepatic sinusoids -> central veins -> hepatic veins -> IVC

is by the enteric nervous system, which in the stomach consists of the myenteric plexus of Auerbach only

modulated by the parasympathetic and sympathetic nervous systems

pregang cell bodies -> dorsal nucleus of vagus

pregang axons -> run in CN X -> enter anterior and posterior vagal trunks

postgang cell bodies -> in enteric nervous system, some are the tranditional postgang parasymps, that release ACh

postgang axons -> terminate on mucosal glands and smooth muscle

pragang cell bodies -> IML cell columns of T5-9

pregang axons -> form greater splanchnic nerve

postgang cell bodies -> in celiac ganglion (part of prevertebral ganglia)

postgang axons -> synapse in complex circuitry of enteric nervous system

gastric ulcers

most often occur where

% of ulcer cases

complications

clinical findings

most often single ulcer within body of stomach along lesser curvature above incisura angularis

25% of ulcer cases

complications -> bleeding from the left gastric artery, perforation

burning epigastric pain soon after eating, pain increases with food intake, pain is relieved with antacids, pt is afraid of eating, possible weight loss

carcinomas of the stomach

commonly found where, metastasizes where

most commonly found in pylorus

may metastasize to supraclavicular lymph nodes (above clavicle; near, above and connected to thoracic duct) on left side -> palpable within posterior triangle of neck

may also metastasize to the ovaries -> krukenberg tumor

parts of the duodenum

(names only)

four parts:

superior/1st

descending/2nd

horizontal/3rd

ascending/4th

1st part

begins at the pylorus of stomach (gastroduodenal junction), which is marked by the prepyloric vein (drains into right gastric vein)

first 2 cm -> duodenal cap, intraperitoneal, mobile

remaining distal 3cm -> retroperitoneal

posterior relationships: common bile duct, gastroduodenal artery (from common hepatic artery)

hepatoduodenal ligament attaches superiorly and greater omentum attaches inferiorly

2nd part

retroperitoneal

receives the common bile duct and main pancreatic duct on posterior/medial wall at: hepatopancreatic ampulla (of Vater)

3rd part

retroperitoneal

runs horizontally across the L3 vertebra between superior mesenteric vessels anteriorly and aorta and IVC posteriorly

area can possibly get crushed against L3 vertebra during severe abd injuries

4th part

ascending to meet the jejunum at duodenojejunal junction at approximately at L2, about 2-3 cm left of midline

duodenojejunal junction typically forms acute angle: duodenojejunal flexure -> supported by ligament of Treitz

part closest to horizontal part -> retroperitoneal

part closest to jejunum -> intraperitoneal

structure that supports the duodenojejunal flexure (at the junction)

represents the cranial end of the dorsal mesentery

goes from flexure up to and slightly around esophagus at the hiatus

the anotomic landmark for the distiction between upper and lower GI gtract bleeds

superior epigastric artery is a branch of what artery

found where (between what structures)

branch of the internal thoracic artery

(internal thoracic artery branches into musculophrenic and superior epigastric arteries at intercostal space 6)

superior epigastric artery -> pierces through posterior layer of rectus sheath and lays on posterior surface of rectus abdominus

(between rectus abdominus and posterior wall of rectus sheath)

inferior epigastric artery is a branch off of what artery

found where (between what structures)

branch off of external iliac artery

(right before external iliac artery passes deeply to the inguinal ligament and becomes the femoral artery)

pierces through posterior layer of rectus sheath and found on posterior surface of rectus abdominus

(originates inferior to arcuate line (still posterior to rectus abdominus), but then travels above arcuate line -> piercing through rectus sheath)

inferior epigastric artery

deep circumflex iliac artery

superficial circumflex iliac artery

(runs in subcutaneous tissue parallel and inferior to inguinal ligament)

superficial epigastric artery

(travels in subcutaneous tissue toward umbilicus, crossing over the inguinal ligament)

superior epigastric artery and inferior epigastric artery

collateral circulation between the subclavian artery (superior epi) and the external iliac (inferior epi)

drains into axillary vein

lateral thoracic vein -> axillary vein -> subclavian vein -> brachiocephalic vein -> SVC

the thoracoepigastric vein

may exist or develop between the superficial epigastric vein (going to femoral vein) and the lateral thoracic vein (going to axillary vein)

a superficial venous collateral circulation between the femoral vein and axillary vein -> during a blockage of either vena cava

inferior epigastric vein anastomosing with superior epigastric vein and/or internal thoracic vein

deep venous collateral circulation between the external iliac vein and subclavian vein -> during a blockage and either vena cava

varicose superficial epigastric veins

as a clinical consideration

aka - Hesselbech's triangle

inguinal ligament

rectus abdominus

inferior epigastric vessels

gubernaculum in males -> scrotal ligament, attaching the testes to the infeiror scortal wall

gubernaculum in females -> becomes the round ligament of the uterus

**I am not sure if this is exactly right, this is my understanding from looking at netters and his lecture, but not 100%, let me know if I am wrong, please!*

Renal arteries

vertebral level

L1

project laterally from abdominal aorta

supply the kidneys

arterial supply of the duodenum

(names only)

supraduodenal artery

anterior and posterior superior pancreaticoduodenal arteries

anterior and posterior inferior pancreaticoduodenal arteries

supraduodenal artery

supplies what and from where

supplies upper portion of duodenum

abd aorta -> celiac trunk -> common hepatic artery -> gastroduodenal artery -> supraduodenal artery

anterior and posterior superior pancreaticoduodenal arteries

from where

both from gastroduodenal artery, posterior superior branches off of gastroduodenal first and then anterior superior branches off

abd aorta -> celiac trunk -> common hepatic artery -> gastroduodenal artery -> anterior and posterior superior pancreaticoduodenal

supply the duodenum, and the HEAD and NECK of the pancreas

anterior and posterior inferior pancreaticoduodenal arteries

from where

abd aorta -> superior mesenteric artery -> (in netters: inferior pancreaticoduodenal artery) -> anterior and posterior inferior pancreaticoduodenal arteries

supply the duodenum, and the HEAD and NECK of the pancreas

venous drainage of duodenum

(names only)

anterior and posterior superior pancreaticoduodenal veins

anterior and posterior inferior pancreaticoduodenal veins

anterior and posterior superior pancreaticoduodenal veins

drain into

anterior and posterior inferior pancreaticoduodenal veins

drain into

duodenal ulcers

most commonly found where

% of ulcer cases

complications

clinical findings

most often occur on anterior wall of duodenal cap, and then on posterior wall

75% of ulcer cases

may erode gastroduodenal artery, poss severe hemorrhage, perforate pancreas -> pancreatitis

perforation -> poss air under diaphragm, radiating pain to left shoulder

burning epigastric pain 1-3 hours after eating, pain decreases with food intake, pain relieved by antacids, pt doesn't lose weight, pt wakes at night because of pain

jejunum

general features

villi -> long, finger shaped

>3cm diameter

initial 2/5 of small intestine

umbilical region on left side of abd

long vasa recta, few arcades

main site of nutrient absorption

from the vasa recta

abd aorta -> superior mesenteric artery -> jejunal arteries -> 1-2 arterial arcades ->  vasa recta

veins associated with the arcades

veins associated with arcades -> jejunal veins -> superior mesenteric vein -> portal vein -> hepatic sinusoids -> central veins -> hepatic veins -> IVC

ileum

general features

villi -> short club shaped

<3cm diameter

terminal 3/5 of small intestine

hypogastric and inguinal regions on right side of abd

short vasa recta, more arcades

site of Vit B12, and H20/electrolyte absorption

site of bile recirculation

ileum

arterial supply

from the vasa recta

abd aorta -> superior mesenteric artery -> ileal arteries -> 3-4 arterial arcades -> vasa recta

ileum

venous drainage

veins associated with the arcades

veins associated with the arcades -> ileal veins -> superior mesenteric vein -> portal vein -> hepatic sinusoids -> central veins -> hepatic veins -> IVC

innervation of small intestine (duodenum, jejunum, ileum)

(names only)

motor and sensory components of submucosal plexus of Meissner (in small intestine and large intestine)

control what

motor component -> controls mucosal and submucosal gland secretion and blood flow

sensory component -> mucosal mechanosensitive neurons

motor and sensory components of myenteric plexus of Auerbach (in small intestine and large intestine)

control what

motor component -> GI motility (contraction/relaxation of GI smooth muscle)

sensory component -> tension-sensitive neurons and chemosensitive neurons

pregang cell bodies -> dorsal nucleus of vagus

pregang axons -> run in CN X -> reach small intestine via posterior vagal trunk

postgang cell bodies -> in enteric nervous systm. some are traditional postgang neurons that release ACh

postgang axons -> terminate on mucosal glands and smooth muscle

pregang cell bodies -> IML cell column of T8-T12

pregang axons -> form greater, lesser and least thoracic splanchnic nerves

postgang cell bodies -> celiac ganglion and superior mesenteric ganglion (both part of prevertebral ganglia)

postgang axons -> synapes in complex circuitry of enteric nerv systm

ileocolic artery right colic artery

ileocolic ven and right colic vein

both from superior mesenteric artery, both to superior mesenteric vein

marginal artery

found mainly along the transverse colon

proximal 2/3 of transverse colon -> supplied by the middle colic artery; drains to middle colic vein (from superior mesenteric artery; to superior mesenteric vein)

distal 1/3 of transverse colon -> left colic artery; left colic vein (from inferior mesenteric artery; to inferior mesenteric vein)

upper portion of descending colon -> supplied from the left colic artery, drains to left colic vein (from inferior mesenteric artery; to inferior mesenteric vein)

left colic artery also supplies distal third of transverse colon

lower portion of descending colon -> supplied from sigmoid arteries; drains to sigmoid veins (from inferior mesenteric artery; inferior mesenteric vein)

idiopathic, chronic inflammatory bowel disease -> most commonly affects ileum

abundant accumolation of lymphocytes -> form granuloma (typical of Crohn) -> found within submucosa, may extend to muscularis externa.

neutrophils infiltrate intestinal glands -> destroys glands -> leads to ulcers

progressive -> ulcers coalesce -> form long serpentine ulcers (linear) along long axis of bowel

clear demarcation between diseased bowel segments directly next to uninvolved normal bowel -> cobblestone appearance

intermitten bouts of diarrhea, weight loss, weakness

complications include -> strictures of intestinal lumen, formation of fistulas, perforation

idiopathic, inflammatory bowel disease

always involves rectum, extends proximally for varying distances

inflammation is continuous (unlike Crohn)

dysplasia or cancer may be present (this is less likely in Crohn)

blood diarrhea with mucus and pus, malaise, fever, weight loss, anemia

may lead to toxic megacolon, adenocarcinoma

innervation of large intestine

(names only)

parasympathetic innervation of large intestine

proximal to splenic flexure

pregang cell bodies -> dorsal nucleu of vagus

pregang axons -> run in CN X -> reach large intestine proximal to splenic flexure via superior mesenteric nerve plexus

postgang cell bodies -> located in enteric nerv systm, some are traditional postgang parasymp neurons that release ACh

postgang axons -> terminate of mucosal glands and smooth muscle

parasympathetic innervation of large intestine

distal to splenic flexure

pregang cell bodies -> gray matter of S2-4

pregang axons -> form the pelvic splanchnic nerves -> reach large intestine distal to splenic flexure via inferior hypogastric plexus

postgang cell bodies -> located in enteric nerv systm, some are traditional postgang parasymp that release ACh

postgang axons -> terminate on mucosal glands and smooth muscle

sympathetic innervation of large intestine

proximal to splenic flexure

pregang cell bodies -> IML cell column of T8-T12

pregang axons -> form greater, lesser and least thoracic splanchnic nerves

postgang cell bodies -> located in celiac ganglion and superior mesenteric ganglion (both part of prevertebral ganglia)

postgang axons -> reach large intestine proximal to splenic flexure via superior mesenteric plexus -> synapse in complex circuitry of enteric nerv systm

sympathetic innervation of large intestine

distal to splenic flexure

pregang cell bodies -> IML cell column of L1-L2

pregang axons -> form lumbar splanchnic nerves (L1, L2)

postgang cell bodies -> located in inferior mesenteric ganglion (part of prevert ganglia)

postgang axons -> reach large intestine distal to splenic flexure via inferior mesenteric plexus -> synapse in complex circuitry of enteric nerv systm

sympathetic innervation

pregang cell bodies -> IML cell column of L2-L3

pregang axons -> form lumbar splanchnic nerves (L3, L4)

postgang cell bodies -> located in superior hypogastric plexus

postgang axons -> reach rectum and upper anal canal via rectal plexus -> synapse in complex circuitry of enteric nerv systm

appendix

general features

intraperitoneal, narrow, muscular tube attached to posteromedial surface of cecum

located about 2.5 cm below ileocecal valve

following positions in can lie: retrocecal (65%) (retrocecal fossa), pelvis (32%), subcecal (2%), anterior juxta-ileal (1%), posterior juxta-ileal (.5%)

suspended by the mesoappendix

supply from the appendicular artery

off of the ileocolic artery from superior mesenteric artery

drainage to posterior cecal vein

joins superior mesenteric vein

begins with obstruction of appendix lumen with fecal concretion (fecalith) and lymphoid hyperplasia -> distension of appendix

initial pain in umbilical or epigastric region, later pain localizes to right lumbar region

N/V, anorexia, tenderness to palpation and percussion in right lumbar region

complications: appendix rupture -> peritonitis

 draw a line from the right anterior superior iliac spine to the umbilicus

midpoint of this line -> root of the appendix

gallbladder

general features

divided into:

fundus -> anterior portion

body

neck -> posterior portion

hartmann pouch

rokitansky-aschoff sinuses

hartman pouch -> small pouch that may extend form the neck as a sequela to pathologic changes

common site for gallstones to lodge

rokitansky-aschoff sinuses -> occure when mucosa of gallbladder penetrates deep into the muscularis externa.

early indicator of pathologic changes -> acute cholecystitis, gangrene)

supplied by the cystic artery

a branch off of the right hepatic artery

abd aorta -> celiac trunk -> common hepatic artery -> proper hepatic artery -> right hepatic artery -> cystic artery

drained to cystic vein directly into the portal vein

pregang cell bodies -> dorsal nucleus of vagus

pregang axons -> run in CN X

postgang cell bodies -> located within the wall of the gallbladder

postgang axons -> terminate on smooth muscle and stimulate gallbladder contraction

pregang cell bodies -> IML cell column of T5-T9

pregang axons -> form thoracic greater splanchnic nerve

postgang cell bodies -> located in celiac ganglion (part of prevertebral ganglia)

postgang axons -> terminate on smooth muscle and inhibit gallbladder contraction

sensory cell bodies -> dorsal root ganglia of right phrenic nerve (C3-5)

peripheral process -> to gallbladder

central process -> spinal cord

responsible for somatic referred pain associated with gallbladder disease

cystic duct

general features

mucosa of the cystic duct is arranged in a spiral fold with a core of smooth muscle knows as the spiral valve (valve of Heister)

the spiral valve keeps the cystic duct constantly open so that bile can flow freely in either direction

an area of thickened smooth muscle of the hepatopancreatic ampulla (the opening into the descending part of the duodenum) that surrounds the bile duct as it is traversing through the ampulla

controls bile flow -> sympathetic innervation causes contraction on sphincter

cholelithiasis

and types

presence or formation of gallstones

gallstones found in the gallbladder -> cholecystolithiasis

gallstones found in the common bile duct ->  choledocholithiasis

gallstones

and types

form when bile salts and lecithin are overwhelmed by cholesterol.

cholesterol stones -> yellow, large, smooth, 4 F's: female, fat, fertile, over forty; associated with Crohn disease, CF, clofibrate, rapid weight loss, US/ Native american pop

pigment (bilirubin) stones -> brown, black, smooth, associated with chronic RBC hemolysis (sickle cell, spherocytosis), alcoholic cirrhosis, biliary infection, asain pop

calcium bilirubinate stones -> associated with infection and/or inflammation of the biliary tree.

most clinically important sites of gallstone obstruction

(names only)

within cystic duct

within common bile duct

at the hepatopancreatic ampulla

may cause biliary colic pain within epigastric region due to distention of the duct

bile flow from the gallbladder is obstructed -> inflammation of gallbladder (acute cholecystitis) and pain will shift to right hypochondriac region

bile becomes [  ]ed and precipitates in gallbladder -> forming layer of high-density material: milk of Ca2+ bile (due to large amount of calcium carbonate

bile flow from liver -> open = no jaundice

may lead to Mirizzi syndrome

caused by gallstone obstruction in the cystic duct

impaction of a large gallstone in the cystic duct extrinsically obstructs the nearby common bile hepatic duct

bile flow from both gallbladder and liver will be obstructed -> inflammation of gallbladder and liver

jaundice -> frequently observed, first observed clinically under the tongue

jaundice is moderate and fluctuates since a stone rarely causes complete blockage of the lumen

bile flow from both the gallbladder and liver will be onstructed

pancreatic duct may be blocked as well

in this case -> pancreatitis and jaundice frequently observed

liver stroma begins as what

extends to where

liver stroma begins as thin connective tissue capsule called: Glisson capsule, extends into liver, around portal triads, and around periphery of a hepatic lobule

extends into perisinusoidal space of Disse -> surrounds hepatocytes

terminates around the central vein

common bile duct

portal vein

hepatic artery

lymphatic vessels

(COA includes: hepatic nerve plexus)

4 lobes

right lobe

left lobe

quadrate lobe

caudate lobe

right lobe and left lobe divided by the interlobar fissure -> which is different than the falciform ligament

invisible line running from gallbladder to IVC

the free, inferior border of the falciform ligament is the round ligament of the liver/ligamentum teres

round ligament of the liver is the remnant of the left umbilical vein

anterior segment of right lobe

posterior segment of right lobe

medial segment of left lobe

lateral segment of left lobe

caudate lobe

the hepatic veins define the segment boundaries

posterior superior

posterior inferior

anterior superior

anterior inferior

medial superior

medial inferior -> quadrate lobe

lateral superior

lateral inferior

caudate lobe

arterial supply: from the right and left hepatic arteries

abd aorta -> celiac trunk -> common hepatic artery -> proper hepatic artery -> right and left hepatic arteries -> hepatic sinusoids

portal supply: from the portal vein

superior mesenteric, splenic, and inferior mesenteric veins -> portal vein -> hepatic sinusoids

venous drainage: to the central veins located at the center of a CLASSIC liver lobule

central veins -> hepatic veins -> IVC

exact function of both parasympathetic and sympathetic innrvation is unclear

except -> sympathetics play a role in vasoconstriction

performed by needle puncture through the right intercostal space 8.9. or 10 (right hypochondriac region) -> during exhalation (hold breath after exhalation)

pass through: skin -> superficial fascia (camper and scarpa) -> external oblique -> intercostal muscles -> costal parietal pleura -> costodiaphragmatic recess -> diaphragmatic parietal pleura -> diaphragm -> peritoneum

(if performed during inhalation -> size of costodiaphragmatic recess is decreased b/c of lung expansion -> more likely to puncture lung)

removing one of the liver segments (of the 5 total) or one of the liver subsegments (of the 9 total)

use hepatic veins as the surgical landmarks making the periphery (or border) of a liver segment during segmental resection

pancreas

general features

retroperitoneal

15-20 cm in length, 85-120 g in weight

both exocrine AND endocrine

four parts:

head -> lies in concavity of C-shaped duodenum, firmly attached to descending and horizontal parts of duodenum,

inferior projection on head: uncinate process

neck -> related posteriorly to confluence of superior mesenteric VEIN and splenic vein to form portal vein

body -> related posteriorly to aorta, superior mesenteric ARTERY, left suprarenal gland, left kidney, renal vessels

tail -> related to splenic hilum and left colic flexure

arterial supply of pancreas

(names only)

anterior and posterior superior pancreaticoduodenal arteries

anterior and posterior inferior pancreaticoduodenal arteries

dorsal pancreatic artery

great pancreatic artery

caudal pancreatic arteries

what arteries supply the head and neck of the pancreas

(names only)

anterior and posterior superior pancreaticoduodenal

anterior and posterior inferior pancreaticoduodenal

what arteries supply the body and tail of the pancreas

(names only)

dorsal pancreatic artery

great pancreatic artery

caudal pancreatic arteries

dorsal pancreatic artery

supplies what and from where

supplies the BODY and TAIL of pancreas

first thing off of splenic artery

abd aorta -> celiac trunk -> splenic artery -> dorsal pancreatic artery

(found on posterior surface on pancreas)

great pancreatic artery

supplies what and from where

supplies the BODY and TAIL of pancreas

branch off of the splenic artery

abd aorta -> celiac trunk -> splenic artery -> great pancreatic artery

(found on the posterior surface of the pancreas)

caudal pancreatic arteries

supply what and from where

supply the BODY and TAIL of the pancreas

branch off of the splenic artery

abd aorta -> celiac trunk -> splenic artery -> caudal pancreatic arteries

venous drainage of pancreas

(major names only)

splenic vein

superior mesenteric vein

dorsal pancreatic

great pancreatic

caudal pancreatic 

all of these veins drain into the splenic vein which then drains into the portal vein

anterior and posterior inferior pancreaticoduodenal veins

anterior superior pancreaticoduodenal vein

these veins drain into the superior mesenteric vein which then drains into the portal vein

(technically, per netter: posterior superior pancreaticoduodenal vein drains directly into the portal vein)

pregang cell bodies -> dorsal nucleus of vagus

pregang axons -> run as CN X

postgang cell bodies -> located within and/or nearby pancreas

postgang axons -> terminate on pancreatic acinar cells and ductal epithelium

*stimulate pancreatic secretion of pancreatic enzymes and juice*

pregang cell bodies -> located in IML cell column of T5-T9

pregang axons -> form greater thoracic splanchnic nerves

postgang cell bodies -> located in celiac ganglion (part of prevertebral ganglia)

postgang axons -> terminate on pancreatic acinar cells, ductal epithelium, smooth muscle of blood vessels

*inhibit pancreatic secretion, probably by reducing blood flow*

formation of a ring of pancreatic tissue surrounding duodenum

caused by ventral pancreatic bud fusing with dorsal bud both dorsally and ventrally

causes severe duodenal obstruction noticed shortly after birth

newborns: intolerant of feeding, bilious vomiting

radiographically -> indicated by duodenal obstruction, "double bubble": b/c of dilation of stomach and distal duodenum

sigmoid colon

general features

segment of large intestine betwen the desending colon and rectum

primary function -> store feces

intraperitoneal

begins at S1 (sacral promontory) and ends at S3 @ rectosigmoid junction

left ureter and left common iliac artery lie at the apex of the sigmoid colon

teniae coli ends at the rectosigmoid junction @ S3

replaced by a complete circular layer of smooth muscle of the rectum

supplied from sigmoid arteries -> off of the inferior mesenteric artery

drained by the sigmoid veins -> which drain into the inferior mesenteric vein -> splenic vein -> portal vein

Hirschsprung disease

caused by the arrest of caudal migration of neural crest cells -> therefore, absence of ganglionic cells in myenteric and submucosal plexuses, most commonly in sigmoid colon and rectum.

narrowed segment of colon results (colon fails to relax)

ganglionic cells absent, but proliferation of hypertrophied nerve fiber bundles

most characteristic finding: failure of internal anal sphincter to relax following rectal distention -> abnorm rectoanal reflex

colonic aganglionosis

clinical findings

clinical findings:

distended abdomen

inability to pass meconium

gush of fecal material upon a rectal digital exam

fecal retention

loss of peristalsis in colon segment distal to the normal innervated colon

presence of diverticula -> abnormal pouches/sacs

most commonly found in sigmoid colon in pts 60+ yrs

associated with: low fiber, modern western diet

perforation and/or inflammation of diverticula = diverticulitis

clinical findings:

pain in left lumbar region, palpable inflammatory mass in left lumbar region, fever, leukocytosis, ileus, peritonitis

permits examination of sigmoid colon and rectum

possible complications:

punctured large intestine at angle at the rectosigmoid junction is not negotiated properly

at this junction -> sigmoid colon bends in an anterior direction and to the left

the transverse rectal folds must also be negotiated also

sigmoid colon often used due to the mobility rendered by the sigmoid mesocolon.

ostomy -> intestinal diversion that brings out a portion of the GI tract through the rectus abdominus muscle

complications:

may ablate the pelvic splanchnic plexus -> loss of ejaculation, loss of erection, urinary bladder retention, decreased peristalsis of remaining colon

rectum

general features

segment of large intestine between sigmoid colon and anal canal

begins at L3 and ends at tip of coccyx (anorectal junction)

puborectalis muscle -> perineal flexure

ampulla of the rectum

transverse rectal folds

lies just above the pelvic diaphragm

generates the urge to defecate when feces move into it

transverse rectal folds

how many, composed of what (cell layers)

three folds

aka Houston valves

formed by the mucosa, submucosa, and inner circular layer of smooth muscle (doesn't not include outer longitunial muscle layer)

permanently extend into lumen of rectum to support fecal mass

arterial supply and venous drainage of rectum

(names only)

arterial supply:

superior rectal artery

middle rectal artery

inferior rectal artery

venous drainage:

superior rectal artery

middle rectal artery

inferior rectal artery

arterial supply of rectum

from where

superior rectal artery: the terminal branch of the inferior mesenteric artery

middle rectal artery: abd aorta -> common iliac artery -> internal iliac artery -> middle rectal artery

(comes off internal iliac before in terminates into inferior gluteal artery and internal pudendal arteries)

inferior rectal artery: abd aorta -> common iliac a -> internal iliac a -> internal pudendal a -> inferior rectal a

venous drainage of the rectum

to where

superior rectal vein -> goes to inferior mesenteric vein which joins splenic vein

middle rectal vein -> joins the internal iliac vein -> joins common iliac -> drains into IVC

inferior rectal vein -> joins the internal pudendal vein -> joins the internal iliac vein -> common iliac vein -> IVC

which veins draining the rectum go to the portal system

(if any at all)

the superior rectal vein is the only drainage of the rectum that flows to the portal system

the only vein that drains into the inferior mesenteric vein 

all other rectal veins flow back directly to IVC without traveling through portal system

protrusion of full thickness of the rectum through the anus

clinical findings:

bowel protruding through the anus

bleeding

anal pain

mucous discharge

anal incontinence cause by stretching of the internal and external anal sphincter or stretch injury to the pudendal nerve

different that rectal prolapse (which is full thickness of the rectum through the anus)

mucosal prolapse is the protrusion of only the rectal mucosa through the anus (does not include the circular and longitudinal muscle layers)

anal canal

general features

about 4 cm long; extends from rectum @ anorectal junction to surface of the body at anus

upper anal canal

lower anal canal

pectinate line

extends from anorectal junction (perineal flexure) to pectinate line

simple columnar cells

mucosa is thrown into longitudinal folds -> anal columns (of Morgagni)

base of anal columns -> defines pectinate line; are also folds of tissue -> anal valves

surrounded by internal anal sphincter -> a continuation of smooth muscle from rectum -> involuntary control (autonomic)

found in the upper anal canal

small blind pouches

behind the anal valves

where anal glands open into the anal canal

extends from pectinate line to the anal verge (point where perianal skin begins)

stratified squamous cells

predominately surrounded by the external anal sphincter -> striated muscle -> voluntary control

pudendal nerve

voluntary

striated muscle

autonomic nervous system

involuntary

arterial supply and drainage of the anal canal

(names only)

arterial supply:

upper anal canal -> from superior rectal artery (branch of inferior mesenteric artery)

lower anal canal -> from inferior rectal artery (branch of internal pudendal artery)

anastomosis btwn superior and inferior rectals via middle rectal artery

venous drainage:

upper anal canal -> to superior rectal vein (going to portal system)

lower anal canal -> to inferior rectal vein (does NOT go to the portal system)

upper anal canal:

via autonomic nerv systm (parasymp and symp) -> internal anal sphincter under nonvoluntary control

sensation is limited to stretch sensation  (same as lrg intestine innervation)

lower anal canal:

via somatic nervous system -> pudendal nerve -> external anal sphincter -> voluntary control

sensation expanded to pain, temp, and touch

varicosities (enlargement/swelling) of the superior rectal veins (from inferior mesenteric)

located above pectinate line

covered by rectal mucosa

clinical findings:

bleeding, mucous discharge, prolapse, pruritus, PAINLESS

varicosities (enlargement/swelling) of inferior rectal vein

located below pectinate line near anal verge

covered by skin

clinical findings:

bleeding

swelling

PAINFUL

upper anal canal -> from endoderm (hindgut)

lower anal canal -> from ectoderm (proctodeum)

upper anal canal:

palpable enlarged superficial nodes will NOT be found

pts do NOT complain of pain

lower anal canal:

palpable enlarged superficial nodes WILL be found

pts DO complain of pain

feces present -> sensory impulse sent from pressure-sensitive receptors in ampulla of rectum on sacral spinal cord levels

motor impulses travel with pelvic splanchnic nerves (parasymps, S2-4) -> increase peristalsis and relax internal anal sphincter

defecation occurs -> only if external anal sphincter and pudorectalis muscle are also relaxed

defecation also requires with help of anterior abd wall muscle contraction and closure of glottis

pudendal nerve stimulated -> external anal sphincter and pudorectalis muscle voluntarily contracted -> defecation delayed -> feces move back into sigmoid colon for storage