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A) Stomach and spleen

Explanation: The dorsal part of the dorsal mesogastrium gives rise to the stomach and spleen, which are key components in the development of the foregut.

C) It moves to the left

Explanation: As the cecum grows, the apex of the cecum and the base of the appendix are pushed towards the left, resulting in the base of the appendix being attached to the posteromedial wall of the cecum near the ileocecal junction.

A) Foregut, Midgut, Hindgut

Explanation: The text identifies the three main parts of the primitive gut as the foregut, midgut, and hindgut, which are essential for understanding the development of the digestive tract.

C) It corresponds with the termination of the bile duct in the duodenum

Explanation: The anterior intestinal portal is the junction between the foregut and midgut, and its position in the adult gut corresponds with the termination of the bile duct in the second part of the duodenum.

C) It serves as an apron-like fold of peritoneum

Explanation: The greater omentum is described as a large apron-like fold of peritoneum that extends from the greater curvature of the stomach, playing a significant role in the anatomy of the digestive tract.

C) Endodermal

Explanation: The lower half of the anal canal is endodermal in origin and develops from the anal pit known as the proctodeum.

D) All parts of the gastrointestinal tract

Explanation: The primitive gut, which develops from the dorsal part of the endodermal yolk sac, forms the endothelial lining of all parts of the gastrointestinal tract, except for parts derived from ectoderm.

B) Celiac trunk

Explanation: The celiac trunk is specifically mentioned as the artery that supplies the foregut, making it crucial for understanding the vascularization of this part of the digestive tract.

C) It supplies the anterior surface

Explanation: Due to the stomach's rotation, the left vagus nerve, which initially supplied the left surface, now supplies the anterior surface of the stomach.

B) To divide the foregut into the esophagus and trachea

Explanation: The tracheoesophageal septum plays a crucial role in separating the foregut into the esophagus and trachea, which is essential for proper respiratory and digestive function.

B) It contributes to the muscular coat

Explanation: The splanchnopleuric mesoderm is involved in forming the muscular coat of the gut, which is essential for the movement and function of the digestive tract.

B) An embryonic structure that develops into the cecum

Explanation: The cecal bud is an embryonic structure that ultimately develops into the cecum, highlighting its importance in gut formation.

B) The transverse colon passes behind the duodenum

Explanation: In reversed rotation, the midgut loop rotates clockwise instead of anticlockwise, resulting in the transverse colon passing behind the duodenum and lying behind the superior mesenteric artery.

B) Buccopharyngeal membrane

Explanation: The cranial end of the foregut is separated from the stomodeum by the buccopharyngeal membrane, which plays a crucial role in the early development of the digestive tract.

B) It allows communication between the primitive gut and the yolk sac

Explanation: The vitellointestinal duct facilitates the communication between the primitive gut and the remaining yolk sac, which is crucial during early development.

C) It completely obliterates

Explanation: The vitellointestinal duct, also known as the omphaloenteric tract, normally completely obliterates by the tenth week of intrauterine life, which is a crucial developmental milestone.

B) Cardiac end moves to the left and slightly downward; pyloric end moves to the right and slightly upward

Explanation: The rotation of the stomach causes the cardiac end to shift left and downward while the pyloric end moves right and upward, altering their original midline positions.

B) It allows the duodenal loop to fall on the right side

Explanation: The clockwise rotation of the stomach to the left results in the duodenal loop falling on the right side, which is an important aspect of the anatomical positioning of the digestive organs.

B) Greater curvature to the posterior abdominal wall

Explanation: The dorsal mesogastrium initially extends from the greater curvature of the stomach to the posterior abdominal wall, playing a role in the stomach's positioning and support.

B) It twists around the superior mesenteric artery

Explanation: During the rotation of the midgut loop, the dorsal mesentery twists around the superior mesenteric artery, which is a significant developmental change.

B) Celiac trunk

Explanation: The proximal half of the duodenum develops from the foregut and is supplied by the celiac trunk, which is critical for understanding its blood supply.

B) A remnant of the vitellointestinal duct

Explanation: Meckel’s diverticulum is a small diverticulum that persists in about 2% of cases where a remnant of the vitellointestinal duct remains after the normal obliteration process.

C) Cecum

Explanation: The postarterial segment of the midgut loop gives rise to the terminal part of the ileum, cecum, appendix, ascending colon, and proximal two-thirds of the transverse colon.

C) 85%

Explanation: The surgical correction of esophageal atresia has an 85% survival rate, indicating a relatively high success rate for this congenital anomaly.

B) Polyhydramnios

Explanation: In esophageal atresia, the fetus is unable to swallow amniotic fluid, leading to an abnormal increase in amniotic fluid known as polyhydramnios.

A) A condition where the gut fails to communicate with the exterior

Explanation: Imperforate anus is a clinical condition where the lower part of the gastrointestinal tract does not connect to the exterior, leading to various complications.

B) Pencil-shaped narrowing (bird beak deformity)

Explanation: In achalasia cardia, a barium swallow reveals a pencil-shaped narrowing of the lower part of the esophagus, known as bird beak deformity, due to failure of relaxation of the musculature.

C) Superior mesenteric artery

Explanation: The superior mesenteric artery is responsible for supplying all parts derived from the midgut, highlighting its crucial role in the vascularization of this region during development.

C) Twice, around both longitudinal and anteroposterior axes

Explanation: The stomach rotates twice during development: first around its longitudinal axis and then around its anteroposterior axis, which contributes to its final shape and position.

C) Normal type

Explanation: The normal type of cecum is the most prevalent in adults, accounting for 80-90% of cases, indicating its typical anatomical presentation.

B) It separates the hindgut from the proctodeum

Explanation: The cloacal membrane separates the caudal end of the hindgut from the proctodeum, and its rupture allows communication with the exterior.

A) Hox and ParaHox genes, and sonic hedgehog (SHH) signals

Explanation: The molecular regulation of regional differentiation of the primitive gut is primarily controlled by Hox and ParaHox genes, along with sonic hedgehog (SHH) signaling.

A) Esophageal atresia

Explanation: Esophageal atresia occurs due to the failure of recanalization of the developing esophagus, often leading to associated conditions like tracheoesophageal fistula.

B) Vomiting every feed

Explanation: Tracheoesophageal fistula typically presents with an infant vomiting every feed, and the presence of air in the stomach is a diagnostic sign.

C) Minor form with anal membrane failure to breakdown

Explanation: In this minor form of imperforate anus, the anal membrane develops normally but fails to break down, causing a bulging effect due to accumulated contents.

B) Imperforate anus

Explanation: Rectal fistulae are frequently seen in association with imperforate anus, indicating a connection between these two conditions.

B) A dilated part of the hindgut distal to the allantois

Explanation: The cloaca is the terminal dilated part of the hindgut, which is divided by the urorectal septum into the primitive urogenital sinus and the primitive rectum.

B) The midgut loop elongates rapidly

Explanation: During the third week of IUL, the midgut loop undergoes rapid elongation, particularly in its prearterial segment, which is significant for subsequent developmental processes.

B) A failure of the small intestine to return to the abdominal cavity

Explanation: Exomphalos or omphalocele is a congenital anomaly resulting from the failure of the small intestine coils to return to the abdominal cavity during the sixth to tenth week of intrauterine life.

C) First part

Explanation: The first part of the duodenum is derived from the foregut, while the second part up to the opening of the common bile duct is also derived from the foregut.

B) It rotates 90° clockwise around its longitudinal axis

Explanation: The stomach first rotates 90° clockwise around its longitudinal axis, resulting in the repositioning of its surfaces and altering the nerve supply to those surfaces.

B) It is absorbed and becomes retroperitoneal

Explanation: The mesoduodenum is absorbed during development and eventually becomes retroperitoneal, indicating a change in its anatomical position and function.

B) First and second parts

Explanation: The first and second parts of the duodenum, up to the opening of the common bile duct, are derived from the foregut, while the distal half comes from the midgut, indicating the dual origin of the duodenum.

B) It attaches to the posterior abdominal wall in the midline

Explanation: The dorsal mesentery (mesentery proper) is crucial as it connects the midgut loop to the posterior abdominal wall, providing support during the development of the digestive tract.

B) A fusiform dilatation of the foregut

Explanation: The stomach appears as a fusiform dilatation of the foregut distal to the esophagus during the fourth week of intrauterine life, marking an important stage in its development.

C) Hindgut and proctodeum

Explanation: The anal canal develops from both the hindgut and the proctodeum, with the upper half being endodermal in origin from the primitive rectum.

D) Stomach

Explanation: The stomach is not considered part of the midgut; it is part of the foregut, while the other options are components of the midgut.

B) Anal membrane

Explanation: Initially, the two parts of the anal canal are separated by the anal membrane, which later ruptures to allow communication between the two parts.

B) Conical

Explanation: At birth, the cecum is described as having a conical shape, which later changes as it grows and develops in the infant.

B) Incomplete recanalization of the duodenum

Explanation: Duodenal stenosis occurs due to incomplete recanalization of the duodenum, resulting in a narrow lumen that can lead to partial obstruction.

C) Endoderm

Explanation: The epithelial lining and gastric glands of the stomach are derived from the endoderm of the primitive foregut, highlighting their embryonic origin.

B) It is confused with congenital umbilical hernia

Explanation: Students often confuse exomphalos with congenital umbilical hernia, highlighting the need for clear differentiation between these two congenital anomalies.

B) A failure of the vitellointestinal duct to obliterate completely

Explanation: A vitelline fistula occurs when the vitellointestinal duct fails to obliterate along its entire length, resulting in a communication between the ileum and the umbilicus, allowing ileal contents to discharge through the umbilicus.

B) The stomach is pulled up into the diaphragm

Explanation: In short esophagus, the esophagus fails to elongate during development, causing the stomach to be pulled up into the esophageal hiatus of the diaphragm, which can lead to congenital hiatal hernia.

D) A condition where the intestine twists along its mesentery

Explanation: Volvulus occurs when a portion of the intestine twists around its mesentery, potentially compromising blood supply and leading to ischemic necrosis if not corrected in time.

C) Differential growth of the dorsal border

Explanation: The greater curvature of the stomach is formed by the differential growth of the dorsal border, which grows more than the ventral border, leading to the characteristic shape of the stomach.

B) Line connecting the cardiac and pyloric ends of the stomach

Explanation: The longitudinal axis of the stomach is defined by the line connecting the cardiac and pyloric ends, which is crucial for understanding the stomach's rotation and orientation.

C) The part of the foregut between the pharynx and the stomach

Explanation: The esophagus develops from the foregut, specifically from the section located between the pharynx and the stomach, highlighting its embryological origin.

C) Superior mesenteric artery

Explanation: The superior mesenteric artery is specifically mentioned as supplying the proximal segment of the digestive tract, indicating its crucial role in arterial supply.

B) It fuses with the posterior abdominal wall

Explanation: After the rotation of the gut, the mesentery of the duodenum (except for the first inch) fuses with the parietal peritoneum lining the posterior abdominal wall, becoming retroperitoneal.

B) Herniation of intestinal loops through the umbilical opening

Explanation: The physiological umbilical hernia refers to the temporary herniation of intestinal loops through the umbilical opening during the sixth week of IUL, which is a normal developmental process.

D) 270°

Explanation: The midgut loop undergoes a total rotation of 270° during its return to the abdominal cavity, consisting of three 90° anticlockwise rotations, which is essential for establishing the definitive relationships of the intestine.

B) Herniation of abdominal viscera through a weak umbilical opening

Explanation: A congenital umbilical hernia occurs when abdominal contents protrude through a poorly closed umbilicus, leading to a clinical presentation of a protrusion in the linea alba.

B) They innervate the stomach before rotation

Explanation: Initially, the left and right vagus nerves innervate the left and right sides of the stomach, respectively. Following a 90° clockwise rotation, these sides become the anterior and posterior surfaces, leading to their respective innervation.

B) Gastrosplenic ligament

Explanation: The part of the dorsal mesogastrium that extends from the greater curvature of the stomach to the spleen forms the gastrosplenic ligament, which is an important anatomical structure in the digestive tract.

A) Incomplete esophageal recanalization and vascular abnormalities

Explanation: Esophageal stenosis is caused by incomplete recanalization of the esophagus and vascular abnormalities, leading to a narrowed lumen, particularly in the lower third of the esophagus.

D) Sigmoid colon

Explanation: The sigmoid colon, along with the descending colon and rectum, develops from the hindgut, highlighting the differentiation of the gastrointestinal tract.

C) The middle part of the vitellointestinal duct persists

Explanation: A vitelline cyst forms when the small middle part of the vitellointestinal duct fails to obliterate, leading to the formation of a cyst.

A) A condition where organs are transposed to the opposite side

Explanation: Situs inversus is characterized by all abdominal and thoracic viscera being laterally transposed, such as the appendix and duodenum lying on the left side.

B) A congenital anomaly where the cecum remains below the liver

Explanation: Subhepatic cecum and appendix occur when the cecum does not descend properly and remains permanently below the liver, which can lead to misdiagnosis during appendicitis.

C) Meckel’s diverticulum

Explanation: Meckel’s diverticulum is recognized as the most common congenital anomaly of the intestine, resulting from incomplete closure of the omphalomesenteric duct.

B) Good prognosis, usually reducing on its own

Explanation: Congenital umbilical hernias typically reduce on their own within 2–3 years of life, and surgical intervention is only necessary if the hernia persists beyond this age.

C) Vitelline duct fistula

Explanation: The persistent discharge from the umbilicus and the fluoroscopy findings indicate a vitelline duct fistula, which results from the failure of the vitelline duct to close during development.

B) It connects the duodenal loop to the posterior abdominal wall

Explanation: The mesoduodenum serves as the mesentery that connects the developing duodenal loop to the posterior abdominal wall, playing a crucial role in its support and positioning.

C) Esophagus

Explanation: The foregut gives rise to several structures, including the esophagus, making it a key derivative of this part of the primitive gut.

B) Descent of the diaphragm

Explanation: The elongation of the esophagus is attributed to the descent of the diaphragm, along with the formation of the neck and the descent of the heart and lungs.

B) 90° anticlockwise, then 180° anticlockwise

Explanation: The midgut loop undergoes a 90° anticlockwise rotation followed by a 180° anticlockwise rotation as it is withdrawn into the abdominal cavity, which is crucial for proper gut positioning.

B) It descends later in development

Explanation: The text indicates that the descent of the cecum occurs later in the development process, which is an important aspect of gut anatomy.

B) To help in the retraction of herniated loops of intestine into the abdominal cavity

Explanation: The rotation of the gut plays a crucial role in retracting herniated loops back into the abdominal cavity and establishing the definitive relationships of various parts of the intestine.

C) Omphalocele involves physiological herniation

Explanation: Omphalocele is characterized by herniation of bowel loops through the umbilical opening as a normal developmental event, which fails to return to the abdominal cavity, unlike congenital umbilical hernia.

B) It involves herniation lateral to the umbilicus

Explanation: Gastroschisis is characterized by a linear defect in the anterior abdominal wall through which abdominal contents herniate out, typically occurring to the right of the umbilicus.

A) Site of anal membrane

Explanation: The pectinate line in adults represents the site where the anal membrane was located during development.

C) Superior mesenteric artery

Explanation: The postarterial segment of the midgut loop is primarily supplied by the superior mesenteric artery, which plays a crucial role in the vascularization of the midgut.

A) Double bubble sign

Explanation: The 'double bubble sign' seen in X-ray or ultrasound indicates duodenal atresia, which occurs due to the failure of recanalization of the duodenum.

A) Celiac artery, superior mesenteric artery, inferior mesenteric artery

Explanation: After the disappearance of most ventral branches of the dorsal aorta, only the celiac artery (foregut), superior mesenteric artery (midgut), and inferior mesenteric artery (hindgut) remain.

A) Lesser omentum

Explanation: The ventral mesogastrium is divided into two parts during liver development, with the part extending from the stomach to the liver becoming the lesser omentum.

C) Superior mesenteric artery

Explanation: The right two-thirds of the transverse colon is supplied by the superior mesenteric artery, which is associated with the midgut development.

B) The large intestine occupies the left side of the abdominal cavity

Explanation: In the nonrotation anomaly, the midgut loop fails to rotate, resulting in the large intestine occupying the left side of the abdominal cavity while the small intestine occupies the right side.

C) Cecum and appendix

Explanation: The cecal bud, which appears in the postarterial segment of the midgut loop, develops into the cecum and appendix, with the proximal part forming the cecum and the distal part forming the appendix.

B) They pass behind the superior mesenteric artery

Explanation: During the second 90° anticlockwise rotation, the coils of jejunum and ileum pass behind the superior mesenteric artery, which is an important step in the rotation process.

B) Omphalocele

Explanation: The description of a shiny mass covered by a thin membrane suggests an omphalocele, which occurs when abdominal contents herniate through the umbilical ring.

C) It persists in relation to a small portion adjoining the pylorus

Explanation: The mesoduodenum is noted for its persistence in relation to a small portion of the duodenum that is adjacent to the pylorus, which is important for understanding its anatomical relationships.

B) Congenital hypertrophic pyloric stenosis

Explanation: Congenital hypertrophic pyloric stenosis occurs due to the hypertrophy of the circular muscle layer at the pylorus, leading to obstruction and significant clinical symptoms in newborns.

B) A congenital anomaly where the intestine fails to return to the abdominal cavity

Explanation: Exomphalos, also known as omphalocele, occurs when the intestine fails to return to the abdominal cavity during the tenth week of intrauterine life, leading to a significant congenital anomaly.

C) It rapidly loses its shiny appearance

Explanation: Once the transparent membrane covering exomphalos is exposed to air, it quickly loses its shiny appearance and becomes thicker, eventually getting covered with an opaque fibrinous exudate.

A) Upper one-third

Explanation: The upper one-third of the esophagus is characterized by striated musculature, while the middle has mixed musculature and the lower has smooth musculature.

B) The first 180° of rotation occurs normally

Explanation: In partial rotation, the first 180° of rotation occurs normally, but the last 90° does not, causing the cecum and appendix to be located just below the pylorus of the stomach instead of the right side.

B) Continuous pouring of saliva from mouth

Explanation: The continuous pouring of saliva from the mouth is a key sign indicating esophageal atresia, as it suggests that the saliva cannot pass into the stomach.

C) 270°

Explanation: The midgut undergoes a total anticlockwise rotation of 270° during its return to the abdominal cavity, which is essential for proper intestinal positioning.

C) It increases in size

Explanation: The size of a congenital umbilical hernia increases during crying, coughing, and straining due to increased abdominal pressure, which can exacerbate the herniation.

B) Duodenal atresia

Explanation: The symptoms of bile in the vomitus and epigastric distention suggest duodenal atresia, which is caused by incomplete recanalization of the duodenum during development.

B) A small part of the vitellointestinal duct that persists

Explanation: Meckel’s diverticulum is formed when a small part of the vitellointestinal duct near the midgut (ileum) persists, leading to a diverticulum that can cause various complications.

B) Failure of neural crest cell migration

Explanation: Congenital megacolon is produced due to the failure of migration of neural crest cells in the wall of the affected segment of the colon, leading to the absence of peristalsis.

C) Umbilical sinus

Explanation: An umbilical sinus occurs when part of the vitellointestinal duct near the umbilicus fails to close, leading to a communication with the umbilicus.

B) Hirschsprung’s disease

Explanation: Congenital megacolon is clinically referred to as Hirschsprung’s disease, characterized by a dilated segment of the colon due to the absence of autonomic parasympathetic ganglia.

C) Sigmoid colon or rectum

Explanation: Congenital megacolon is commonly seen in the sigmoid colon or rectum, where the affected segment lacks autonomic ganglia.

B) Somatic

Explanation: The lower half of the anal canal has a somatic nerve supply, contrasting with the autonomic supply of the upper half.

B) Loss of peristalsis, fecal retention, and abdominal distension

Explanation: Clinically, congenital megacolon presents with loss of peristalsis, fecal retention, and abdominal distension due to the obstruction caused by the affected segment.

D) Upper half receives blood from the superior rectal artery

Explanation: The upper half of the anal canal is supplied by the superior rectal artery, while the lower half is supplied by the inferior rectal artery.