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What is the primary name given to the more common form of congenital diaphragmatic hernia?
What is the incidence rate of congenital diaphragmatic hernia in live births?
Which statement about the diaphragm and associated hernias is correct?
What effect does congenital diaphragmatic hernia have on the affected lung?
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Which anatomical feature is typically compromised due to congenital diaphragmatic hernia?
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What structure is formed in the umbilicus during embryonic development?
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At what stage are the lungs considered unneeded and given priority to other structures?
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Which of the following structures is NOT part of the umbilical cord?
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Which cavity is connected to the primitive intestine via the vitelline duct?
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What is the primary purpose of the allantois during embryonic development?
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Which of the following best describes the primitive intestine?
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Which structure provides a connection for the embryo to the developing placenta?
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What happens to the wall of the amniotic cavity as development progresses?
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Which region of the gastrointestinal tract is supplied by the coeliac trunk?
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What is the role of the splanchnic intraembryonic mesoderm in gut development?
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Which arteries supply the midgut during development?
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What anatomical structure does the septum transversum contribute to during development?
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From which embryonic tissue does the diaphragm primarily develop?
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What distinguishes congenital hernias from acquired hernias?
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Which membrane separates the pleural and peritoneal cavities?
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Which structure is the central tendon of the diaphragm associated with?
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What is the embryological origin of the epithelial lining of the digestive tract?
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Which of the following is NOT a component of the ventral mesentery?
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What is the role of the hypoblast during the formation of the germ layers?
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Which structure connects the yolk sac to the developing gut tube during embryonic development?
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What occurs during the longitudinal folding of the embryo?
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What is the significance of the pericardial cavity during development?
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During which day of development do primordial germ cells originate?
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In the early stages of embryonic development, what are the three primary germ layers formed?
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What does the dorsal mesogastrium develop into in adults?
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What is the relationship between the foregut and developing structures in the embryo?
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What condition may arise due to developmental issues with the diaphragm?
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What is a possible clinical significance of an accessory spleen?
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What is the consequence of hypertrophy of the pyloric sphincter in newborns?
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What occurs if the duodenum fails to recanalize during development?
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How does the stomach develop its distinctive shape during growth?
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Where does the spleen originate during embryonic development?
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What are the symptoms of pyloric stenosis in infants?
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What signifies the presence of an accessory spleen in an individual?
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Which of the following describes a common clinical feature of duodenal atresia?
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What is primarily affected when there is marked dilatation of the epigastrium in an infant?
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What is the primary anatomical location associated with a Hernia of Bochdalek?
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Which condition results in the stomach being anchored partly into the thorax?
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What is the most common effect on the lung affected by congenital diaphragmatic hernia?
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What is the percentage of cases for congenital diaphragmatic hernia that occur on the left side?
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What term is used to describe the opening in the diaphragm where a Hernia of Bochdalek occurs?
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Which structure serves as a link between the embryo and the yolk sac during early development?
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What is the main purpose of the allantois in embryonic development?
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What essential structure forms from the folding of the embryo after the fourth week of gestation?
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Which structures are included in the umbilicus during embryonic development?
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What does the dorsal aorta primarily supply during the early stages of development?
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How does the amniotic cavity evolve as the embryo continues to grow?
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What role does the vitelline duct play in the connection between the embryo and external structures?
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What is the significance of the formation of the pleural cavities in relation to lung development?
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What anatomical structure is primarily affected by pyloric stenosis in an infant?
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Which symptom is most characteristic of pyloric stenosis in infants?
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What developmental issue may lead to duodenal atresia?
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During which specific process does the spleen begin to form in the embryonic stage?
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What physiological consequence can a blockage at the pyloric sphincter lead to in a newborn?
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Which clinical sign may suggest the presence of an accessory spleen?
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What is a common radiological finding in a case of duodenal atresia?
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How does the stomach achieve its distinctive shape during development?
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What is the primary cause of projectile vomiting in the 5-week-old male neonate presented in the clinical vignette?
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Which developmental process contributes to the separation of the trachea and esophagus?
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What complication is likely with tracheoesophageal fistula in infants during feeding?
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Which statement accurately describes oesophageal atresia in infants?
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What is the most common type of tracheo-oesophageal malformation?
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Which statement accurately defines the role of the splanchnic intraembryonic mesoderm in gut development?
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Which artery supplies the foregut during embryonic development?
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What is a primary anatomical structure derived from the septum transversum?
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Which mesentery is responsible for forming the greater omentum?
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What contributes to the nerve supply of the diaphragm?
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What is one of the key functions of the allantois during embryonic development?
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Which structure is primarily responsible for separating the pleural and peritoneal cavities?
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Which structure does the inferior mesenteric artery provide blood supply to?
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Which embryonic layer is responsible for the epithelial lining of the digestive tract?
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Which anatomical feature is commonly associated with congenital hernias?
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What are the three germ layers formed during early embryonic development?
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Which ligament provides support to the liver and attaches it to the anterior abdominal wall?
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During which phase of embryonic development does the gut tube become established?
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What do the terms 'mesentery' and 'omentum' refer to in anatomical context?
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What is the clinical significance of understanding embryological development?
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Which division of the gut tube gives rise to the small intestine?
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Which structure is primarily responsible for connecting the developing gut tube to the yolk sac?
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Which of the following structures is NOT derived from the embryonic mesoderm?
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Study Notes
Gastrulation
- The three germ layers form from the epiblast during gastrulation.
- The primitive streak forms, and mesoderm cells invaginate.
- Invaginated cells displace the hypoblast and form the endoderm.
- Cells between the epiblast and newly formed endoderm form the mesoderm.
- The remaining epiblast cells form the ectoderm.
Yolk Sac
- Blood cells are generated in the wall of the yolk sac.
- The yolk sac is the origin of primordial germ cells.
- The yolk sac is connected to the midgut.
- The yolk sac is connected to the hindgut.
- The yolk sac is connected to the foregut.
- The yolk sac is connected to the amniotic sac.
Body Folding
- Longitudinal folding incorporates the endodermal layer into the body of the embryo, forming the gut tube.
- Transverse folding folds the surface ectoderm and amniotic cavity around the gut tube.
- The gut tube becomes evident during transverse folding.
Coelom Formation
- The coelom is divided into two parts: the pericardiopleural canals and the peritoneal cavity.
- The pericardiopleural canals will form the pleural cavities.
- The peritoneal cavity is the main body cavity.
Umbilicus Formation
- The umbilicus forms during the completion of body folding.
- The umbilicus contains the vitelline duct, allantois, two umbilical arteries, and one umbilical vein.
- The amniotic cavity wall fuses onto these structures.
- The embryo floats in the amniotic sac, connected to the placenta via the umbilical cord.
Overview of Gut Development
- The gut tube forms after four weeks.
- The gut tube is lined by endoderm.
- The gut tube is connected to the yolk sac via the vitelline duct and the allantois.
Gut Tube Regions
- Pharyngeal gut: buccal membrane to respiratory diverticle (mouth cavity; head and neck).
- Foregut: up to the hepatic bud (oesophagus, stomach, first half of duodenum, liver, and pancreas).
- Midgut: up to the left third of the transverse colon.
- Hindgut: up to the cloaca.
Arterial Supply
- The pattern of arterial supply is determined early in embryogenesis and is rarely variable.
- Coeliac trunk: supplies the foregut below the diaphragm.
- Superior mesenteric artery: supplies the midgut.
- Inferior mesenteric artery: supplies the hindgut.
Endoderm and Mesoderm Derivatives
- Endoderm: epithelial lining of the digestive tract, specific cells of glands, hepatocytes, exocrine & endocrine cells of the pancreas.
- Splanchnic intraembryonic mesoderm: stroma (connective tissue), muscle, visceral layer of peritoneum.
Mesenteries
- Dorsal mesentery: greater omentum (includes dorsal mesogastrium, dorsal mesoduodenum, mesentery proper, dorsal mesocolon).
- Ventral mesentery: derived from the septum transversum, which divides into the lesser omentum and falciform ligament.
Septum Transversum
- It is mesodermal tissue that extends from the thorax to the stalk of the yolk sac.
- It contributes to the ventral mesentery, liver, and diaphragm.
Diaphragm Formation
- The diaphragm is formed from the septum transversum, myotomes of C3, C4, and C5, the body wall, and the dorsal mesentery.
- The central tendon of the diaphragm is derived from the septum transversum.
- Myotomes of C3, C4, and C5 provide the diaphragm's nerve supply (phrenic nerve).
- The pleuroperitoneal membrane contributes to the diaphragm from the body wall.
- The dorsal mesentery also makes a contribution to the diaphragm.
Diaphragm Attachments
- Peripheral attachments: lumbar vertebrae (right and left crurae and arcuate ligaments), costal cartilages of ribs 7-10, ribs 11 and 12, xiphisternum.
- Central attachments: central tendon fuses with the fibrous pericardium.
Diaphragmatic Hernias
- Congenital hernias: occur when the coelom does not divide properly, leaving an opening (foramen of Bochdalek) between the pleural and peritoneal cavities.
- Acquired hernias: occur later in life due to a weakening of the diaphragm.
- Hernia of Bochdalek: the most common type of congenital diaphragmatic hernia, occurs on the left side.
- Hernia of Morgagni: occurs when the diaphragm fails to fuse anteriorly, accounting for 3% of congenital diaphragmatic hernias.
- Congenital short oesophagus: anchors the stomach partly into the thorax, giving it a 'Figure 8' appearance.
Stomach Development
- Rapid cell growth transforms the stomach tube into a sac.
- Growth is more rapid posteriorly, along the greater curvature, giving the stomach its shape.
- The stomach rotates 90 degrees.
Omental Bursa Formation
- The omental bursa (lesser sac) forms during stomach rotation.
Spleen Development
- The spleen forms as a mesodermal proliferation between the two leaves of the dorsal mesogastrium.
- Initially, it appears as isolated islands that then coalesce into a single organ.
- The spleen moves to the left as the stomach and dorsal mesogastrium rotate.
Accessory Spleen
- An accessory spleen occurs in 10% of the population.
- It is clinically relevant after splenectomy.
Pyloric Stenosis
- Hypertrophy of the pyloric sphincter, caused by excessive cell growth at the outflow of the stomach.
- Projectile vomiting is a characteristic symptom, usually occurring at 6-8 weeks of age.
- A hard "chestnut" can be felt in the epigastrium after feeding.
Duodenal Atresia
- Failure of the duodenum to recanalise after development.
- Abdominal distension, vomiting, and absent bowel movements are common symptoms.
- Vomiting can be bilious or non-bilious, depending on the level of obstruction.
Clinical Vignette
- A premature baby with bile-containing vomit, marked epigastric dilatation, and absent bowel sounds on X-ray likely has duodenal atresia.
Clinical Correlates
- Pyloric stenosis: excessive cell growth at the pyloric sphincter results in projectile vomiting.
- Duodenal atresia: failure of the duodenum to recanalise leads to abdominal distension, vomiting, and absent bowel movements.
- Accessory spleen: a benign finding that is clinically relevant after splenectomy.
Formation of the Umbilicus
- Folding occurs about halfway through the embryonic period.
- The umbilicus forms during this process.
- Structures in the umbilicus include the vitelline duct, allantois, two umbilical arteries, and one umbilical vein.
- The amniotic cavity fuses onto these structures.
- The embryo floats within the amniotic sac, connected to the developing placenta by the umbilical cord.
Overview of Gut Development (Early Stages)
- Folding after 4 weeks leads to the formation of the Gut Tube or Primitive Intestine.
- The Gut Tube is lined by endoderm.
- It connects to two cavities lined by the same epithelium: the yolk sac and allantois.
Overview of Gut Development (Division)
- The Gut Tube is divided into three sections:
- Pharyngeal gut: from buccal membrane to respiratory diverticle.
- Foregut: from the pharyngeal gut to the hepatic bud (including esophagus, stomach, first half of duodenum, liver, and pancreas).
- Midgut: from the foregut to the left third of the transverse colon .
- Hindgut: from the midgut to the cloaca.
Blood Supply of the Gut Tube
- The dorsal aorta gives rise to three branches that supply the gut tube:
- Celiac trunk: supplies the foregut.
- Superior mesenteric artery: supplies the midgut.
- Inferior mesenteric artery: supplies the hindgut.
Endoderm and Mesoderm Derivatives
- Endoderm:
- Epithelial lining of the digestive tract.
- Specific cells of glands, such as hepatocytes, exocrine & endocrine pancreatic cells.
- Splanchnic intraembryonic mesoderm:
- Stroma (connective tissue).
- Muscle.
- Visceral layer of peritoneum.
Mesenteries
- Dorsal mesentery: forms the greater omentum (dorsal mesogastrium, dorsal mesoduodenum, mesentery proper, dorsal mesocolon).
- Ventral mesentery: derived from the septum transversum, which divides into the lesser omentum and falciform ligament.
Septum Transversum
- Mesodermal tissue extending from the thorax to the yolk sac stalk.
- Derivatives:
- Ventral mesentery.
- Contributes to the liver.
- Diaphragm.
Formation of the Diaphragm
- The diaphragm is formed from:
- The septum transversum: Central tendon.
- Myotomes of C3, C4, and C5: bring nerve supply with them (phrenic nerve).
- Body wall: Pleuroperitoneal membrane.
- Dorsal mesentery.
Peripheral Attachments of the Diaphragm
- Lumbar vertebrae: right and left crurae, and arcuate ligaments.
- Costal cartilages of ribs 7-10.
- Ribs 11 and 12.
- Xiphisternum.
Central Attachments of the Diaphragm
- Central tendon fuses with the fibrous pericardium.
Diaphragmatic Hernias
-
Congenital Hernias:
- Occur when the coelom doesn't fully divide into three separate cavities, resulting in an opening called the Foramen of Bochdalek.
- Abdominal viscera can herniate through this foramen into the pleural cavity, leading to a Hernia of Bochdalek.
- Incidence: 1:2,000 births.
- Most common on the left side.
- Hernia of Morgagni: occurs when the diaphragm fails to fuse anteriorly.
- Congenital Short Esophagus: anchors the stomach partly into the thorax.
-
Acquired Hernias:
- More common than congenital hernias.
- Sliding Hiatus Hernia: the stomach slides up into the chest through the esophageal hiatus.
- Para-esophageal Hiatus Hernia: a portion of the stomach protrudes through the esophageal hiatus alongside the esophagus but doesn't slide into the chest.
Lung Development (Foregut Derivatives)
- Respiratory diverticulum buds off the foregut.
- Tracheo-esophageal ridges deepen.
- Trachea and esophagus separate (remain joined only at the larynx).
- Diverticulum splits to form two lung (bronchial) buds, which further split into lobes.
Tracheo-esophageal Malformations
- Tracheoesophageal fistula: fluid (milk) runs into the lungs during feeding, causing coughing and turning blue (cyanosis).
-
Esophageal atresia: fluid (milk) has nowhere to go during feeding and comes back up.
- Clinical Significance: This usually occurs during feeding and is more common in premature babies.
Stomach Development
- Rapid cell growth transforms the tube-like structure into a sac.
- Growth is faster posteriorly, along the greater curvature, which gives the stomach its distinctive shape.
- The stomach rotates 90 degrees.
Formation of the Omental Bursa/Lesser Sac
- The spleen primordium appears as a mesodermal proliferation between the two leaves of the dorsal mesogastrium.
Pyloric Stenosis
- Hypertrophy of the pyloric sphincter, which causes projectile vomiting.
- Occurs most often in infants between 6-8 weeks old.
- A hard "chestnut" may be felt in the epigastrium after feeding.
Duodenal Atresia
- Occurs when the duodenum fails to recanalize.
- Leads to abdominal distension, vomiting, and absent bowel movements.
- The vomiting may be bilious or non-bilious, depending on the level of the atresia.
Spleen Development
- Forms within the dorsal mesentery.
- Initially, there are isolated islands of mesodermal tissue that coalesce.
- The spleen moves leftward as the stomach and dorsal mesogastrium rotate.
- 10% of people have an accessory spleen.
Clinical Vignettes
- Clinical Vignette 1: 5-week-old male neonate presents with projectile vomiting. Ultrasound reveals a thickened pyloric muscle (suggestive of pyloric stenosis).
- Clinical Vignette 2: Premature female infant vomits bile within hours of birth, with marked epigastric dilatation. Radiographs show gas in the stomach and superior duodenum, but no gas in other intestinal segments (suggestive of duodenal atresia).
Embryological Development
- Fertilization marks the beginning of embryonic development.
- Gastrulation establishes the three germ layers: ectoderm, mesoderm, and endoderm.
- Ectoderm gives rise to skin, nervous system, and sensory organs.
- Mesoderm forms muscle, bone, blood, and connective tissue, including ligaments.
- Endoderm develops into the lining of the digestive and respiratory systems.
Formation of the Gut Tube
- Gastrulation forms the gut tube, a primitive digestive tract.
- The gut tube differentiates into the foregut, midgut, and hindgut.
- Foregut derivatives include the esophagus, stomach, and part of the duodenum.
- Midgut forms the small intestine, cecum, and ascending colon.
- Hindgut develops into the descending and sigmoid colon, rectum, and anus.
Development of Ligaments and Mesenteries
- Mesenteries are double layers of peritoneum that suspend organs and carry blood vessels and nerves.
- Ligaments are strong bands of connective tissue that provide support and stability to organs.
- Falciform ligament connects the liver to the anterior abdominal wall.
- Lesser omentum suspends the stomach and duodenum from the liver.
- Greater omentum drapes over the intestines and serves as a protective layer.
Organ Development
- Liver, pancreas, spleen, and digestive tract develop from the foregut, midgut, and hindgut.
- Organ formation and maturation occur throughout gestation.
Vascular and Nervous System Development
- Vascular system develops alongside developing organs, providing blood supply.
- Nervous system interacts with mesenteries and ligaments, contributing to organ function.
Clinical Relevance
- Congenital anomalies related to ligaments and embryological structures can occur.
- Understanding embryological processes aids in surgical considerations and diagnosis of congenital malformations.
Interaction between Structures
- The relationship between embryological structures and associated ligaments is crucial for organ support and function.
- This interaction shapes the overall abdominal architecture.
Key Terms
- Ligament: Strong band of connective tissue providing support.
- Mesentery: Double layer of peritoneum suspending organs.
- Omentum: Specific mesenteries supporting the stomach and intestines.
- Peritoneum: Membrane lining the abdominal cavity.
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Description
Explore the fundamental processes of embryological development with this quiz on gastrulation, yolk sac formation, and body folding. Understand the formation of germ layers, yolk sac functions, and coelom formation. Test your knowledge on key stages that shape the embryo.
