Stomach development | Embryology

Summary

This video provides a detailed explanation of the developmental embryology of the stomach, focusing on the formation of the greater and lesser curvatures, mesenteries, and ligaments. It covers the early stages of stomach development, from the foregut gut tube to its rotation, the formation of ligaments like the greater and lesser omentum, and the development of associated structures like the liver, pancreas, and spleen. The video also explains how key ligaments such as the hepatogastric, gastrocolic, and splenorenal ligaments form and their significance in anatomy and surgery.

Takeaways

• 😀 The stomach develops from a straight gut tube in the foregut region of the embryo, which is initially simple before undergoing significant changes.
• 😀 The gut tube is divided into three components: foregut, midgut, and hindgut. The stomach develops from the foregut.
• 😀 The peritoneum, a connective tissue layer, forms two mesenteries: the dorsal mesentery (becomes dorsal mesogastrium) and the ventral mesentery (becomes ventral mesogastrium).
• 😀 The dorsal mesogastrium suspends the gut tube to the back wall and is renamed to form the greater omentum as development progresses.
• 😀 The ventral mesogastrium becomes the lesser omentum, which attaches the liver to the stomach and the duodenum.
• 😀 The stomach undergoes a 90-degree clockwise rotation during its development, which shifts the left vagus nerve to the anterior and the right vagus nerve to the posterior.
• 😀 The rotation of the stomach creates the greater curvature on the left and the lesser curvature on the right, setting up the future stomach anatomy.
• 😀 As the stomach continues to rotate, it also undergoes a second rotation in the anterior-posterior plane, further positioning the pylorus and esophagus.
• 😀 Ligaments such as the hepatogastric ligament (liver to stomach) and the hepatoduodenal ligament (liver to duodenum) are formed from the ventral mesentery.
• 😀 The greater omentum flops down to form an apron-like structure over the transverse colon, giving rise to ligaments like the gastrocolic ligament, gastrosplenic ligament, and splenorenal ligament.
• 😀 The lesser sac (or lesser bursa) forms behind the stomach, and the epiploic foramen (Foramen of Winslow) provides a crucial access point for surgeons to reach this space.

Q & A

Why does the stomach have ligaments during development?

Ligaments in the stomach are formed from the mesenteries, which are folds of peritoneum that attach the developing stomach to the abdominal wall. These ligaments help to stabilize the stomach and other associated structures during embryonic development, providing a supportive framework for the growing organs.

How do the greater and lesser curvatures of the stomach develop?

The curvatures form as the stomach undergoes rotations. Initially, the stomach is a simple tube, but as it grows, it bulges out at the back, creating the greater curvature, while the front part forms the lesser curvature. These curvatures are further defined during the 90-degree rotations of the stomach during development.

What is the greater omentum and how does it develop?

The greater omentum is a large fold of peritoneum that hangs down from the greater curvature of the stomach. It develops from the dorsal mesogastrium and becomes a structure that drapes over the intestines, helping to anchor the stomach and intestines. It also plays a role in immune response and fat storage.

What is the significance of the lesser omentum in stomach development?

The lesser omentum is a peritoneal fold that forms between the liver and the stomach. It originates from the ventral mesentery and includes the hepatogastric and hepatoduodenal ligaments. These ligaments are essential for blood vessel connections, containing the hepatic artery, portal vein, and bile duct.

How does the stomach rotate during development?

The stomach undergoes two key rotations: a 90-degree clockwise rotation around its long axis and a subsequent 90-degree rotation in the anterior-posterior plane. This rotation positions the pylorus to the right and up and the fundus to the left and down, forming the adult shape of the stomach.

What are the ligaments associated with the greater omentum?

The greater omentum forms several important ligaments, including the gastrocolic ligament, which connects the stomach to the transverse colon, and the gastrosplenic ligament, which connects the stomach to the spleen. These ligaments are part of the mesogastrium and are crucial for maintaining the position and stability of the stomach.

What is the function of the hepatogastric ligament?

The hepatogastric ligament connects the liver to the stomach, forming part of the lesser omentum. It contains important blood vessels, such as the left and right gastric arteries, and helps anchor the stomach to the liver, aiding in blood supply and structural stability.

What is the role of the epiploic foramen (Foramen of Winslow)?

The epiploic foramen is an opening that allows access from the greater sac (the main body cavity) into the lesser sac (a space behind the stomach). This space is critical for surgical procedures, as it provides a route to access structures such as the pancreas, spleen, and liver.

How does the pancreas develop in relation to the stomach?

The pancreas develops from a dorsal and ventral bud that grows into the dorsal mesogastrium, which becomes part of the greater omentum. As the stomach rotates, the pancreas becomes positioned behind it and is anchored to the back wall of the abdominal cavity, with a connection to the spleen.

What happens to the umbilical artery and vein after birth?

The umbilical vein, which carried blood from the placenta to the fetus, becomes obliterated after birth and forms the round ligament of the liver. The umbilical artery, which carried deoxygenated blood to the placenta, is also obliterated, leaving behind remnants in the fetal circulation.