Embryonic Development and Anatomy

Questions and Answers

What occurs when the intestinal loops return to the abdominal cavity?

Formation of a fixed colon

Permanent adhesion to the abdominal wall

Creation of a mobile colon that can twist (correct)

Increased risk of omphalocele

What is a retrocolic hernia?

A condition involving herniation of the liver through the umbilical ring

Entanglement of the entire colon within the small intestine

A defect in the body wall leading to bowel obstruction

Entrapment of parts of the small intestine behind the ascending colon (correct)

What is the initial orientation of the stomach during its formation in the 4th week?

Median plane (correct)

Horizontal plane

Transverse plane

Coronal plane

Which of the following best describes an omphalocele?

Herniation of abdominal viscera through an enlarged umbilical ring Signup and view all the answers

What is the consequence if the stomach remains in the thoracic cavity?

Diaphragmatic hernia Signup and view all the answers

What type of cells innervate the gut tube?

Vagal neural crest cells and lumbosacral neural crest cells Signup and view all the answers

During which weeks of development does the rotation of the midgut occur?

Weeks 6, 8, and 10 Signup and view all the answers

At what angle does the stomach rotate around its longitudinal and anteroposterior axes?

90° Signup and view all the answers

Which nerve innervates the anterior side of the stomach after positional changes during development?

Right vagus nerve Signup and view all the answers

What structural feature develops faster in the stomach, contributing to its shape?

Posterior wall Signup and view all the answers

Which part of the stomach moves right and upward during its development?

Caudal/pyloric part Signup and view all the answers

What happens to the positions of the cephalic and caudal ends of the stomach during development?

They remain in the midline Signup and view all the answers

What is the structure formed on the ventral surface of the stomach following the changes during development?

Anterior Vagal Trunk Signup and view all the answers

What is the primary function of the lesser omentum?

It connects the stomach and proximal duodenum to the liver. Signup and view all the answers

Which ligament connects the liver to the body wall?

Falciform ligament Signup and view all the answers

The continuous structure with the dorsal mesentery is primarily associated with which aspect of embryonic development?

Development of the gastrointestinal tract Signup and view all the answers

Which section of the gastrointestinal tract is described as having a smooth muscle coat in the lower third?

Lower third of the stomach Signup and view all the answers

What significant anatomical change occurs during tail folding in embryonic development?

Incorporation of the allantois Signup and view all the answers

What occurs at the end of the fourth week of embryonic development regarding the intraembryonic cavity?

It begins losing its connection with the extraembryonic cavity. Signup and view all the answers

The peritoneal reflection is primarily defined as what?

The junction between organ and the inner posterior abdominal wall. Signup and view all the answers

What characterizes the splanchnic plexus in relation to muscle coats?

It is composed of smooth muscle fibers. Signup and view all the answers

What is the likely cause of a defect that results in the colon positioning on the left side of the abdominal cavity?

Abnormal closure of the abdominal wall Signup and view all the answers

What primarily occurs during the reversed rotation of the intestinal loop?

The loop rotates 90° clockwise Signup and view all the answers

What is a potential consequence of a volvulus in the bowel?

Fetal death due to compromised blood supply Signup and view all the answers

What abnormality could occur as a result of abnormalities in the formation of the cloaca?

Rectourethral fistulas Signup and view all the answers

Where are duplications of intestinal loops likely to occur?

Throughout the length of the gut tube Signup and view all the answers

What condition occurs in approximately 1 in 5,000 live births?

Rectourethral and rectovaginal fistulas Signup and view all the answers

What anatomical position does the transverse colon achieve in cases of abnormal rotation?

Lies behind the superior mesenteric artery Signup and view all the answers

What mechanism is primarily responsible for the rotation that causes volvulus?

Clockwise rotation of the intestinal loop Signup and view all the answers

What is the primary conduit between the pancreas and the duodenum?

Main pancreatic duct Signup and view all the answers

At which anatomical location does the midgut terminate in adults?

Junction of proximal two-thirds of the transverse colon with distal third Signup and view all the answers

Which structures are derived from the pancreas during gestational development?

Islet of Langerhans Signup and view all the answers

What condition may arise if the vitelline duct persists after development?

Meckel’s diverticulum Signup and view all the answers

Which artery supplies the midgut?

Superior mesenteric artery Signup and view all the answers

During the embryonic period, what structure connects the primary intestinal loop to the yolk sac?

Vitelline duct Signup and view all the answers

Which days of development are associated with the growth from approximately 5mm to 7mm in the pancreas?

30-35 days Signup and view all the answers

Which transcription factors are associated with the specification of pancreatic cells?

PAX 4 and PAX 6 Signup and view all the answers

Study Notes

Development of the Gastrointestinal Tract

The lesser omentum connects the stomach and proximal duodenum to the liver.
The falciform ligament attaches the liver to the body wall and is continuous with the dorsal mesentery.
The peritoneal reflection serves as the junction between an organ and the posterior abdominal wall.

Embryonic Development Highlights

Gastric development begins with the foregut around the fourth week; initial formation is fusiform dilation.
Essential growth in the esophageal region positions the stomach within the abdominal cavity.
A diaphragmatic hernia may occur if the stomach remains in the thoracic cavity, leading to lung compression.

Stomach Rotation and Innervation

Stomach rotates 90° around both longitudinal and anteroposterior axes; the pylorus shifts right and upward.
Left vagus nerve innervates the anterior side, while the right vagus innervates the posterior side due to this rotation.
The greater and lesser curvatures of the stomach are formed as the posterior wall grows faster than the anterior wall.

Pancreatic Development

The pancreas develops from parenchymatous tissue, with Islets of Langerhans forming by the third month of gestation.
During development, pancreatic ducts enter the duodenum at significant sites known as the major and minor papillae.

Midgut Overview

The midgut begins immediately distal to the duodenum and terminates at the proximal two-thirds of the transverse colon.
It is supplied by the superior mesenteric artery, which provides blood supply during rapid midgut and mesentery growth.
The primary intestinal loop remains connected to the yolk sac via the vitelline duct, which can persist and form Meckel’s diverticulum if not closed.

Post-Rotation Conditions

Return of intestinal loops into the abdominal cavity involves a complete 270 degrees of rotation.
Potential complications include retrocolic hernia and volvulus due to intestinal twisting.

Body Wall Defects

Omphalocele occurs with herniation of abdominal viscera through an enlarged umbilical ring, potentially involving multiple organs.
Defects like rectourethral and rectovaginal fistulas result from abnormal cloaca formation and urorectal septum development, occurring in 1 in 5,000 live births.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the lesser omentum's role in connecting the stomach and proximal duodenum to the liver, along with the falciform ligament's function. Additionally, it examines transverse sections through embryos at various development stages, enhancing your understanding of embryonic anatomy and connections.