What are the two main parts of the hepatic bud?
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Pars hepatica and pars cystica.
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What are the two main parts of the hepatic bud?
Pars hepatica and pars cystica.
What are the four types of cecum based on shape and appendix attachment?
What is imperforate anus?
A clinical condition where the lower part of the gut fails to communicate with the exterior.
What condition is associated with the failure of union of extrahepatic bile ducts?
Formation of cysts within the liver.
What parts of the pancreas does the dorsal bud form?
Upper part of the head, neck, body, and tail.
What is the difference between omphalocele and congenital umbilical hernia?
Omphalocele involves physiological herniation that fails to return to the abdominal cavity, while congenital umbilical hernia occurs due to a poorly closed umbilicus.
What is Meckel’s diverticulum?
A remnant of the vitellointestinal duct that persists in about 2% of cases.
What is the incidence of exomphalos?
2.5 per 10,000 births.
What is an annular pancreas?
Pancreatic tissue forming a collar around the second part of the duodenum.
What is gastroschisis?
A linear defect in the anterior abdominal wall through which abdominal contents herniate, usually occurring lateral to the umbilicus.
What is a vitellointestinal fistula?
A condition where the entire vitellointestinal duct persists.
How is the main pancreatic duct formed?
From the distal three-fourths of the duct of the dorsal bud and proximal one-fourth of the duct of the ventral bud.
What is a vitelline (umbilical) fistula?
It occurs when the vitellointestinal duct fails to obliterate, communicating with the ileum at one end and opening to the exterior at the umbilicus.
What is the most important confirmatory sign of esophageal atresia?
Continuous pouring of saliva from the mouth.
What is the anatomical feature formed around the second part of the duodenum?
Collar of pancreatic tissue.
What is Riedel’s lobe?
A variant of liver anatomy.
From which part of the midgut loop does the right two-thirds of the transverse colon develop?
From the postarterial segment of the midgut loop.
What is physiological umbilical hernia?
Herniation of intestinal loops through the umbilical opening into the extraembryonic celom.
What are the two main roles of gut rotation?
(a) Helps in the retraction of herniated loops of intestine into the abdominal cavity; (b) Helps in establishing definitive relationships of various parts of the intestine.
What happens to the mesentery of the gut after rotation?
Certain parts fuse with the parietal peritoneum and become retroperitoneal.
What embryonic structure gives rise to liver parenchyma?
Hepatic bud.
Where does the dorsal pancreatic bud arise from?
Dorsal wall of the foregut, above the ventral bud.
What is the most common source of aberrant right hepatic artery?
Superior mesenteric artery.
What is the total degree of anticlockwise rotation of midgut loops during their return to the abdominal cavity?
270°.
What is volvulus?
A condition where a portion of the intestine twists along its mesentery, compromising blood supply.
What are the major glands associated with the digestive tract?
Salivary glands, liver, and pancreas.
What is Hartmann’s pouch?
A pouch formed when the posterior medial wall of the neck of the gallbladder projects downward, often containing gallstones.
What is Meckel’s diverticulum?
A small diverticulum formed from a persistent part of the vitellointestinal duct, located on the antimesenteric border of the ileum.
What is the histogenesis of the spleen derived from?
All elements of the spleen are derived from mesoderm.
What forms the accessory pancreatic duct?
Proximal one-fourth of the duct of the dorsal pancreatic bud.
What structure does the dorsal pancreatic bud form?
The upper part of the head, neck, body, and tail of the pancreas.
What is a septate gallbladder?
A gallbladder that is partially or completely subdivided by a septum.
What happens to blood formation in the spleen after birth?
Blood formation stops after birth, but lymphocyte production continues.
What supplies the left one-third of the transverse colon?
The inferior mesenteric artery.
How many degrees does the midgut loop rotate during its return to the abdominal cavity?
270° (three 90° anticlockwise rotations).
What is the main pancreatic duct also known as?
Duct of Wirsung.
What is an umbilical sinus?
A condition where part of the vitellointestinal duct near the umbilicus persists and communicates with the umbilicus.
What is the significance of the gallbladder in liver development?
It develops alongside the liver and is connected to the hepatic ducts.
What do bile canaliculi and bile ductules develop from?
Derivatives of the hepatic bud.
What are the parts of the gastrointestinal tract that arise from the hindgut?
Left one-third of transverse colon, descending colon, sigmoid colon, rectum, and upper part of the anal canal.
What is the relationship between the ventral pancreatic bud and the hepatic bud?
The ventral pancreatic bud arises close to the hepatic bud.
What happens to the prearterial segment of the midgut loop during the first rotation?
It undergoes 90° anticlockwise rotation, moving to the right side.
What is nonrotation of the midgut loop?
An anomaly where the midgut loop fails to rotate, causing the large intestine to occupy the left side of the abdominal cavity.
What are common types of rectal fistulae?
Rectovaginal, rectovesical, and rectourethral fistulae.
What are some other anomalies related to the liver?
Rudimentary liver, absence of quadrate lobe, and presence of accessory liver tissue in the falciform ligament.
What is exomphalos (omphalocele)?
A congenital anomaly where the intestine fails to return to the abdominal cavity during the tenth week of IUL.
What happens clinically with a vitelline fistula?
Ileal contents may be discharged through the umbilicus.
What are spleniculi?
Accessory spleens.
What complications can arise from Meckel’s diverticulum?
Ulceration, bleeding, perforation, and inflammation mimicking appendicitis.
What is the most common source of aberrant left hepatic artery?
Left gastric artery.
What structures do the umbilical and vitelline veins pass through to enter the sinus venosus?
The septum transversum.
What covers the exomphalos?
A transparent membrane derived from the amnion.
What is a vitelline cyst?
It forms when the small middle part of the vitellointestinal duct persists and fails to obliterate.
What is a floating gallbladder?
A gallbladder that is completely surrounded by peritoneum and attached to the liver by a fold of peritoneum.
What is an accessory spleen?
Accessory nodules of splenic tissue that may be found at various sites.
What is the accessory pancreatic duct also known as?
Duct of Santorini.
What happens to the membrane covering exomphalos when exposed to air?
It rapidly loses its shiny appearance, becomes thicker, and gets covered with an opaque fibrinous exudate.
What is the dorsal pancreatic bud?
A structure involved in the development of the pancreas.
What are the two segments of the midgut loop during its rotation?
Prearterial (cephalic) segment and postarterial (caudal) segment.
What condition occurs when the dorsal and ventral pancreatic buds fail to fuse?
Divided pancreas.
What shape is the cecum at birth?
Conical shape.
What is accessory pancreatic tissue?
Heterotropic small masses of pancreatic tissue found in various locations.
What is the origin of the spleen?
The spleen is mesodermal in origin.
From which embryonic layer do the pancreatic buds develop?
Endoderm.
How does the growth of the cecum affect the position of the appendix?
The apex of the cecum and the base of the appendix is pushed towards the left, nearer to the ileocecal junction.
What is a congenital umbilical hernia?
Herniation of abdominal viscera through a weak umbilical opening, presenting as a protrusion in the linea alba.
How can a congenital umbilical hernia be reduced?
By pushing the intestines back into the abdominal cavity through the umbilical opening.
What is the origin of the hepatic bud?
It arises from the foregut at its junction with the midgut.
What happens to the size of a congenital umbilical hernia during crying or coughing?
The size increases due to increased abdominal pressure.
Where does the spleen develop?
In the dorsal mesogastrium in close relation to the stomach.
When does a congenital umbilical hernia typically reduce on its own?
Within 2–3 years of life.
What is the normal fate of the vitellointestinal duct by the tenth week of intrauterine life (IUL)?
It normally completely obliterates.
What are the small mesenchymal masses that form the spleen called?
Lobules of splenic tissue or spleniculi.
What is the most common site of accessory pancreatic tissue?
Mucosa of the stomach and Meckel’s diverticulum.
What is the significance of the ventral pancreatic bud?
It contributes to the formation of the pancreas and its ducts.
What happens to the dorsal mesentery during the rotation of the midgut loop?
It twists around the superior mesenteric artery.
What artery supplies all parts derived from the midgut?
Superior mesenteric artery.
What is the role of the main pancreatic duct?
It drains most of the pancreatic tissue.
What characterizes Caroli’s disease?
Congenital dilatation of the intrahepatic biliary tree, potentially leading to sepsis, stones, and carcinoma.
What does the ascending colon become as it elongates?
Retroperitoneal by zygosis.
What clinical presentation is associated with exomphalos?
A rounded mass protruding from the umbilicus containing coils of the small intestine covered by a transparent amniotic membrane.
What are the two pancreatic buds involved in the development of the pancreas?
Ventral pancreatic bud and dorsal pancreatic bud.
Where can accessory pancreatic tissue be found?
Wall of duodenum, Meckel’s diverticulum, gallbladder, lower end of esophagus, and wall of stomach.
What are the two pancreatic buds called?
Dorsal bud and ventral bud.
What happens in the condition of inversion of pancreatic ducts?
The main pancreatic duct is formed by the duct of the dorsal pancreatic bud and opens on the minor duodenal papilla.
What is the dorsal mesentery of the midgut loop attached to?
The posterior abdominal wall in the midline.
What is exomphalos or omphalocele?
An anomaly resulting from failure of coils of the small intestine to return into the abdominal cavity during the sixth to tenth week of intrauterine life.
What are the types of imperforate anus?
What is intrahepatic biliary atresia?
A serious anomaly that cannot be surgically corrected, requiring either a liver transplant or leading to the child's death.
What ligaments are formed during the development of the spleen?
Gastrosplenic ligament and splenorenal ligament (lienorenal ligament).
What does the ventral bud form?
Lower part of the head and uncinate process.
What is a rectal fistula?
An abnormal connection between the rectum and another organ, often associated with imperforate anus.
What are the congenital anomalies of the liver characterized as?
They are the rarest anomalies.
What indicates the lobulated origin of the spleen in adults?
The presence of splenic notches on the anterior (superior) border.
What occurs during the third week of intrauterine life (IUL) related to the midgut?
The midgut loop elongates rapidly, particularly its prearterial segment.
What is the most fatal congenital anomaly of the liver?
Intrahepatic biliary atresia.
What condition is characterized by the gallbladder being embedded within the liver?
Intrahepatic gallbladder.
What is the source of liver sinusoids?
Vitelline and umbilical veins within the septum transversum.
What common confusion do students have regarding exomphalos?
They often confuse it with congenital umbilical hernia.
What occurs during partial rotation of the midgut loop?
The first 180° of rotation occurs normally, but the last 90° does not, resulting in the cecum and appendix being located just below the pylorus of the stomach.
What is atresia of the bile duct?
A condition where the bile duct is absent, leading to persistent progressive jaundice in newborns.
Which gland develops from the ectodermal lining of the oral cavity?
Parotid gland.
What is the source of development for the jejunum?
Prearterial segment of midgut loop.
What causes the notches on the superior/anterior border of the spleen?
They are a reflection of the lobular origin of the spleen.
What is the largest gland in the body?
The liver.
What is Riedel’s lobe?
A tongue-like downward extension of the right lobe of the liver.
What are the three sources from which the liver develops?
Endodermal hepatic bud, mesenchyme of septum transversum, and absorbed vitelline and umbilical veins.
What is the fate of the distal part of the cecal bud?
It remains narrow to form the appendix.
What is the clinical significance of Riedel’s lobe?
It may be mistaken for an abnormal abdominal mass.
What is a sessile gallbladder?
A condition where the gallbladder drains directly into the CBD due to absence of the cystic duct.
What is the role of the surrounding mesoderm in pancreatic development?
It develops the capsule, septa, and connective tissue elements of the pancreas.
What is a Phrygian cap?
A shape anomaly of the gallbladder where the fundus folds on itself.
What is the physiological umbilical hernia associated with?
The rapid enlargement of the liver during development.
What is congenital megacolon also known as?
Hirschsprung’s disease.
What happens to the hemopoietic function of the liver after birth?
It is taken over by the spleen and bone marrow.
What developmental failure leads to congenital megacolon?
Failure of migration of neural crest cells.
What type of nerve supply does the lower half of the anal canal receive?
Somatic nerve supply.
What is the most common congenital anomaly of the intestine?
Meckel’s diverticulum.
What is a lobulated spleen?
Persistence of fetal spleen formed due to fusion of small lobules of splenic tissue.
What is the terminal dilated part of the hindgut called?
Cloaca.
What anomaly occurs when the pancreatic tissue surrounds the duodenum?
Annular pancreas.
What causes most anorectal anomalies?
Abnormal partitioning of the cloaca by the urorectal septum.
What develops from the pars cystica of the hepatic bud?
The gallbladder and cystic duct.
What is reversed rotation of the midgut loop?
An anomaly where the midgut loop rotates clockwise instead of anticlockwise, causing the transverse colon to pass behind the duodenum.
What are accessory bile ducts?
Small ducts that may open directly from the liver into the gallbladder, potentially causing bile leakage after cholecystectomy.
What happens to the extrahepatic biliary apparatus during development?
It is initially occluded with epithelial cells but later recanalized.
Where does the ascending colon form in relation to the cecum?
When the cecum descends to the right iliac fossa.
What is the consequence of the bifid ventral pancreatic bud in annular pancreas?
It fails to fuse, causing pancreatic tissue to surround the duodenum.
What is the most probable diagnosis for a newborn with bilious vomiting and epigastric distention?
Duodenal atresia, resulting from incomplete recanalization of the duodenum during the eighth week of intrauterine life.
What is the origin of the upper half of the anal canal?
Endodermal, developing from the primitive rectum.
When do the β cells of islets of Langerhans start secreting insulin?
By the tenth week of intrauterine life (IUL).
What is the name of the sinus tract communicating with the distal part of the ileum in a newborn with a swollen umbilicus?
A fistulous tract, often associated with Meckel's diverticulum.
What can happen to the cecum's position during development?
It may descend only partially in the lumbar region or too much into the pelvic region.
What is the diagnosis for a newborn with a shiny mass protruding from the umbilicus covered by a thin membrane?
Umbilical hernia.
What separates the upper and lower halves of the anal canal initially?
The anal membrane.
When does hemopoiesis begin in the liver during intrauterine life?
At about the sixth week.
What is absent in the affected segment of the colon in Hirschsprung’s disease?
Autonomic parasympathetic ganglia in the myenteric plexus.
How common is congenital megacolon in newborns?
Occurs in 1 in 5000 newborns.
What type of nerve supply does the upper half of the anal canal receive?
Autonomic nerve supply.
What is situs inversus?
A condition where all abdominal and thoracic viscera are transposed to the opposite side.
From which embryonic layer do most digestive glands develop?
Endodermal lining of the gut.
What structures develop from the cecal bud?
Cecum and appendix.
Why is the left lobe of the liver smaller than the right lobe in adults?
The growth rate of the left lobe regresses after the ninth week of intrauterine life due to reduced nutritional and oxygen supply.
Which organs are commonly affected in situs inversus?
Appendix, duodenum, stomach, right atrium, and vena cavas.
What divides the cloaca into the primitive urogenital sinus and primitive rectum?
Urorectal septum.
What are the clinical features of annular pancreas?
Vomiting shortly after birth and double-bubble appearance on abdominal radiograph.
What is the embryological basis for the innervation of the stomach by the vagus nerves?
Initially, left and right vagus nerves innervate the left and right sides of the stomach, respectively. Following a 90° clockwise rotation, they supply the anterior and posterior surfaces.
From which two sources does the anal canal develop?
Hindgut and proctodeum.
What is subhepatic cecum and appendix?
A congenital anomaly where the cecum remains below the liver due to failure of the ascending colon to form or remain short.
What is a choledochal cyst?
A rare cyst that develops due to a weakness in the bile duct wall, which may compress the duct and cause obstructive jaundice.
What is agenesis of the gallbladder?
Absence of the gallbladder due to failure of the pars cystica to develop.
What clinical issue can arise from subhepatic cecum and appendix?
Appendicitis may cause tenderness in the right hypochondrium, potentially leading to a mistaken diagnosis of cholecystitis.
What is Moynihan’s hump?
A condition where the hepatic artery lies in front of the common bile duct, forming a caterpillar-like loop.
What does the pars hepatica of the hepatic bud form?
The liver.
What is the origin of the lower half of the anal canal?
Ectodermal, developing from the anal pit called proctodeum.
What does the pars cystica of the hepatic bud form?
The gallbladder and cystic duct.
What represents the site of the anal membrane in adults?
The pectinate line.
What is Riedel’s lobe?
A tongue-like extension from the right lobe of the liver.
What are the clinical presentations of congenital megacolon?
Loss of peristalsis, fecal retention, and abdominal distension.
What are the differences in arterial supply between the upper and lower halves of the anal canal?
Upper half: Superior rectal artery; Lower half: Inferior rectal artery.
