GIT-Anatomy Flashcards
Tongue development?
1. Ant 2/3 = Pharyngeal arch-1st 2. Post 1/3 = Pharyngeal arch -3rd & 4th 3.
Normal GastroIntestinal Embryology ?
Foregut—esophagus to duodenum at level of pancreatic duct and common bile duct insertion (ampulla of Vater). 4th-6th week of development—stomach rotates 90° clockwise. Left vagus becomes anteriorly positioned, and right vagus becomes posteriorly positioned. Midgut—lower duodenum to proximal 2/3 of transverse colon. 6th week of development—physiologic herniation of midgut through umbilical ring. 10th week of development—returns to abdominal cavity rotating around superior mesenteric artery (SMA), 270° counterclockwise (~180° before 10th week, remaining ~90° in 10th week). Hindgut—distal 1/3 of transverse colon to anal canal above pectinate line
FA-364
Ventral wall defects
1. Omphalocele 2. Gastroschisis
365 FA
Gastroschisis??
1. Paraumbilical herniation of abdominal contents through abdominal wall defect 2.Not covered by peritoneum or amnion A ; “the guts come out of the gap (schism) in the letter G” 3.Not associated with chromosome abnormalities; good prognosis
365
Omphalocele ?
1. Herniation of abdominal contents through umbilicus 2.Covered by peritoneum and amnion 3.Associated with congenital “Onomalies” (eg, trisomies 13 and 18, Beckwith-Wiedemann syndrome) and other structural abnormalities (eg, cardiac, GU, neural tube)
365
Congenital umbilical
hernia ?
Failure of umbilical ring to close after physiologic herniation of midgut. Covered by skin C . Protrudes with intra-abdominal pressure (eg, crying). May be associated with congenital disorders (eg, Down syndrome, congenital hypothyroidism). Small defects usually close spontaneously
365
Tracheoesophageal
anomalies ?
1. Esophageal atresia (EA) 2. distal tracheoesophageal fistula (TEF) 3. polyhydramnios 4. Gasless abdomen in EA 5. TEF-------H type fistula 6. TEF= Allow air in the stomach seen in CXR 7. Cannot pass Nasogastric tube in stomach
FA-366
Hypertrophic pyloric
stenosis ?
1. Pyloric sphincter muscle--Hypertrophy + Hyperplasia 2. Palpable olive mass 3. Most common cause of Gastric Outlet Obstruction 4. Projectile vomiting (2-6) weeks 5. Firstborn male + [Macrolide] 6. Hypokalemia Hypochloremic Metabolic alkalosis 7. Thickened and Lengthened pylorus 8. Tx- surgical incision of pyloric muscle / PYLOROMYOTOMY
Intestinal atresia ?
Presents with bilious vomiting and abdominal distension within first 1–2 days of life. Duodenal atresia—failure to recanalize. X-ray A shows “double bubble” (dilated stomach, proximal duodenum). Associated with Down syndrome
FA-366
Jejunal and ileal atresia ?
disruption of mesenteric vessels (typically SMA) ischemic necrosis of fetal intestine segmental resorption: bowel becomes discontinuous. X-ray may show “triple bubble” (dilated stomach, duodenum, proximal jejunum) and gasless colon. Associated with cystic fibrosis and gastroschisis. May be caused by tobacco smoking or use of vasoconstrictive drugs (eg, cocaine) during pregnancy.
366
Pancreas and spleen
embryology ?
Pancreas—derived from foregut. Ventral pancreatic bud contributes to uncinate process. Both
ventral and dorsal buds contribute to pancreatic head and main pancreatic duct
FA-367
Annular pancreas ?
—abnormal rotation of ventral pancreatic bud forms a ring of pancreatic tissue
encircles 2nd part of duodenum; may cause duodenal narrowing (arrows in A ) and vomiting.
Associated with Down syndrome
367
Pancreas divisum ?
ventral and dorsal parts fail to fuse at 7 weeks of development. Common
anomaly; mostly asymptomatic, but may cause chronic abdominal pain and/or pancreatitis``
367
Spleen Embryology
Spleen—arises in mesentery of the stomach (dorsal mesogastrium, hence, mesodermal), but has
foregut supply (celiac trunk splenic artery).
FA-367
Retroperitoneal
structures ?
SAD PUCKER: Suprarenal (adrenal) glands [not shown] Aorta and IVC Duodenum (2nd through 4th parts) Pancreas (except tail) Ureters [not shown] Colon (descending and ascending) Kidneys Esophagus (thoracic portion) [not shown] Rectum (partially) [not shown]
FA-367
Falciform ligament
Liver to anterior abdominal
wall
Ligamentum teres hepatis
(derivative of fetal umbilical
vein), patent paraumbilical
veins
Derivative of ventral mesentery
Hepatoduodenal
ligament
Liver to duodenum
Portal triad: proper hepatic
artery, portal vein, common
bile duct
Derivative of ventral mesentery
Pringle maneuver—ligament is
compressed manually or with
a vascular clamp in omental
foramen to control bleeding
from hepatic inflow source
(portal vein, hepatic artery) vs
outflow (hepatic veins, IVC)
Borders the omental foramen,
which connects the greater
and lesser sacs
Part of lesser omentum
Hepatogastric
ligament ?
Liver to lesser curvature of
stomach
Gastric vessels
Derivative of ventral mesentery
Separates greater and lesser sacs
on the right
May be cut during surgery to
access lesser sac
Part of lesser omentum
Gastrocolic ligament
Greater curvature and
transverse colon
Gastroepiploic arteries
Derivative of dorsal mesentery
Part of greater omentum
Gastrosplenic
ligament
Greater curvature and spleen
Short gastrics, left
gastroepiploic vessels
Derivative of dorsal mesentery
Separates greater and lesser sacs
on the left
Part of greater omentum
Splenorenal ligament
Spleen to left pararenal space
Splenic artery and vein, tail of
pancreas
Derivative of dorsal mesentery
Portosystemic anastomoses >?
- Esophagus
- Umbilicus
- Rectum
- Transjugular intrahepatic portosystemic shunt
FA-372
Esophagus anastomoses ?
Esophageal varices
Left gastric ↔ esophageal
(drains into azygos)
Umbilicus anastomoses ?
Caput medusae
Paraumbilical ↔ small
epigastric veins (branches
of inferior and superficial
epigastric veins) of the
anterior abdominal wall
372
Rectum anastomoses ?
Anorectal varices
Superior rectal ↔ middle and
inferior rectal
Treatment with a Transjugular Intrahepatic Portosystemic Shunt (TIPS) ?
Treatment with a Transjugular Intrahepatic Portosystemic Shunt (TIPS)
between the portal vein and hepatic vein relieves portal hypertension by shunting blood to the systemic circulation,
bypassing the liver. TIPS can precipitate hepatic encephalopathy due to clearance of ammonia from shunting.
372
Pectinate line ?
- Above pectinate line: internal hemorrhoids,
adenocarcinoma.
2.Below pectinate line: external hemorrhoids,
anal fissures, squamous cell carcinoma.
373
Internal hemorrhoids ?
abnormal distention of
anal venous plexus A. Risk factors include older
age and chronic constipation. Receive visceral
innervation and are therefore not painful.
External hemorrhoids?
receive somatic
innervation (inferior rectal branch of
pudendal nerve) and are therefore painful if
thrombosed.
Anal fissure ?
tear in anoderm below
pectinate line. Pain while pooping; blood
on toilet paper. Located in the posterior
midline because this area is poorly
perfused. Associated with low-fiber diets and
constipation.
373
Portal triad ?
- Portal vein
- Hepatic artery
- Bile duct
374
Blood supply of liver ?
- Portal vein 80%
- Hepatic artery 20%
Kupffer cells ?
Kupffer cells (specialized macrophages) located
in sinusoids clear bacteria and damaged or
senescent RBCs.
374
Hepatic stellate (Ito) cells ?
Hepatic stellate (Ito) cells in space of Disse
store vitamin A (when quiescent) and produce
extracellular matrix (when activated).
Responsible for hepatic fibrosis
