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Questions and Answers
What forms the main pancreatic duct (of Wirsung)?
What forms the main pancreatic duct (of Wirsung)?
The ventral pancreatic bud comes to lie immediately below the bile duct.
The ventral pancreatic bud comes to lie immediately below the bile duct.
False
What condition is caused when the right portion of the ventral pancreatic bud migrates normally while the left migrates in the opposite direction?
What condition is caused when the right portion of the ventral pancreatic bud migrates normally while the left migrates in the opposite direction?
Annular pancreas
The accessory pancreatic duct is also known as the duct of __________.
The accessory pancreatic duct is also known as the duct of __________.
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Match the pancreatic structures with their descriptions:
Match the pancreatic structures with their descriptions:
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In what percentage of cases does the duct system fail to fuse, resulting in a double duct system?
In what percentage of cases does the duct system fail to fuse, resulting in a double duct system?
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Accessory pancreatic tissue only occurs at the distal end of the esophagus.
Accessory pancreatic tissue only occurs at the distal end of the esophagus.
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What does the dorsal bud contribute to in the pancreas?
What does the dorsal bud contribute to in the pancreas?
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What is the main cause of gastroschisis?
What is the main cause of gastroschisis?
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Omphalocele is associated with a higher rate of chromosomal abnormalities than gastroschisis.
Omphalocele is associated with a higher rate of chromosomal abnormalities than gastroschisis.
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What is the survival rate for infants born with gastroschisis?
What is the survival rate for infants born with gastroschisis?
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What is the function of the urorectal septum?
What is the function of the urorectal septum?
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Atresias and stenoses may occur anywhere along the __________.
Atresias and stenoses may occur anywhere along the __________.
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The cloacal membrane ruptures to create only the anal opening for the hindgut.
The cloacal membrane ruptures to create only the anal opening for the hindgut.
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Which of the following factors may cause intestinal atresias in the distal portion of the duodenum?
Which of the following factors may cause intestinal atresias in the distal portion of the duodenum?
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What is the estimated occurrence rate of gastroschisis in births?
What is the estimated occurrence rate of gastroschisis in births?
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What structure separates the endoderm and ectoderm in the cloaca?
What structure separates the endoderm and ectoderm in the cloaca?
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The junction between the endodermal and ectodermal regions of the anal canal is called the _____ line.
The junction between the endodermal and ectodermal regions of the anal canal is called the _____ line.
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Match the following conditions with their descriptions:
Match the following conditions with their descriptions:
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Which artery supplies the cranial part of the anal canal?
Which artery supplies the cranial part of the anal canal?
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Which portion of the hindgut gives rise to the sigmoid colon?
Which portion of the hindgut gives rise to the sigmoid colon?
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Rectourethral and rectovaginal fistulas occur in approximately 1 in 5,000 live births.
Rectourethral and rectovaginal fistulas occur in approximately 1 in 5,000 live births.
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When the anal membrane fails to breakdown, it results in _____ anus.
When the anal membrane fails to breakdown, it results in _____ anus.
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Match the following structures to their corresponding descriptions:
Match the following structures to their corresponding descriptions:
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What does the cephalic limb of the primary intestinal loop develop into?
What does the cephalic limb of the primary intestinal loop develop into?
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The primary intestinal loop rotates 360° clockwise during its development.
The primary intestinal loop rotates 360° clockwise during its development.
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What is omphalocele?
What is omphalocele?
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The movement of the intestinal loops into the extraembryonic cavity is referred to as __________.
The movement of the intestinal loops into the extraembryonic cavity is referred to as __________.
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Match the following parts of the intestine with their respective development:
Match the following parts of the intestine with their respective development:
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During which week of development do the herniated intestinal loops begin to return to the abdominal cavity?
During which week of development do the herniated intestinal loops begin to return to the abdominal cavity?
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The large intestine participates in the coiling phenomenon during its development.
The large intestine participates in the coiling phenomenon during its development.
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What causes omphalocele during fetal development?
What causes omphalocele during fetal development?
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Study Notes
Pancreas Development
- Formed from dorsal and ventral buds of endodermal lining of the duodenum.
- Dorsal bud located in dorsal mesentery; ventral bud near the bile duct.
- Duodenum rotation causes ventral bud to move behind the dorsal bud.
- Ventral bud develops uncinate process and inferior part of the pancreas; dorsal forms the remainder.
- Main pancreatic duct (Wirsung) results from the distal dorsal duct and entire ventral duct.
- Accessory duct (Santorini) may persist from proximal dorsal duct; enters at minor papilla.
- In about 10% of cases, duct systems do not fuse, leading to a double pancreatic duct system.
Pancreatic Abnormalities
- Annular pancreas can occur when portions of the ventral bud migrate abnormally, constricting the duodenum.
- Accessory pancreatic tissue can be present from the distal esophagus to the primary intestinal loop, often found in stomach mucosa or Meckel's diverticulum.
Midgut Development
- Rapid elongation leads to formation of primary intestinal loop connected to yolk sac via vitelline duct.
- Cephalic limb develops the distal duodenum, jejunum, and part of the ileum.
- Caudal limb gives rise to lower ileum, cecum, appendix, ascending colon, and proximal transverse colon.
Physiological Herniation
- Intestinal loops herniate into umbilical cord cavity during sixth week due to rapid growth.
Midgut Rotation
- Intestinal loop rotates 270° counterclockwise around the superior mesenteric artery.
- During the tenth week, herniated loops begin returning to the abdominal cavity, creating coiled loops of small intestine and displacing the cecum to the lower right abdomen.
Anomalies
- Omphalocele: Herniation of viscera through enlarged umbilical ring, covered by amnion; occurs in 2.5/10,000 births, associated with high mortality and severe malformations.
- Gastroschisis: Herniation of contents through body wall without covering, occurring at right umbilicus; seen in 1/10,000 births, better survival outcomes compared to omphalocele.
- Volvulus: Rotation resulting in compromised blood supply, potentially leading to fetal death.
Gut Rotation Defects
- Abnormal rotation causing left-sided colon; can lead to volvulus.
- Reversed rotation allows transverse colon to pass behind duodenum.
- Duplications or cysts may result from gut parenchyma proliferations.
Gut Atresias and Stenoses
- Can occur along the intestine; most commonly in duodenum.
- Caused by failure of recanalization in upper duodenum and vascular accidents below that site.
- Associated conditions include malrotation, volvulus, gastroschisis, and omphalocele.
Hindgut Development
- Develops into the distal transverse colon, descending colon, sigmoid, rectum, and upper anal canal.
- The cloaca serves as the entry point, divided by the urorectal septum into urogenital and hindgut openings.
- The cloacal membrane ruptures by the seventh week, creating anal and urogenital openings.
Hindgut Abnormalities
- Rectourethral and rectovaginal fistulas: Result from cloacal formation issues; may occur in 1/5,000 live births.
- Rectoanal atresias: May present as fibrous remnants or segment loss due to vascular accidents.
- Imperforate anus: Caused by failure of the anal membrane to break down.
Additional Notes
- The superior rectal artery supplies the cranial anal canal, while the inferior rectal arteries supply the caudal anal canal.
- The pectinate line differentiates the transition point between ectodermal and endodermal regions in the anal canal.
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Description
This quiz explores the development of the digestive system, focusing particularly on the pancreas and its formation from the buds originating from the endodermal lining of the duodenum. Understand key anatomical changes and the role of the dorsal and ventral pancreatic buds in the digestive system's development.
