Embryology and Development Practice Questions

Q: The condition shown in the image below is?

Patent urachus. ***Patent urachus*** - A **patent urachus** is a congenital anomaly where the **urachus (embryonic connection between the bladder dome and umbilicus) fails to obliterate**, resulting in a persistent communication between the bladder and umbilicus. - Clinical presentation includes **urine leakage from the umbilicus**, especially with crying or straining, or a **cystic swelling at the umbilicus** that may discharge clear fluid (urine). - The urachus is the remnant of the **allantois** and normally obliterates to form the **median umbilical ligament**. *Patent vitello-intestinal duct* - Also called **patent vitelline duct** or **patent omphalomesenteric duct**, this represents failure of obliteration of the connection between the **ileum and umbilicus**. - Presents with **fecal discharge from umbilicus**, passage of intestinal contents, or prolapsed ileal mucosa (raspberry tumor). - May present as **Meckel's diverticulum** if only the intestinal end persists. *Patent allantois* - The **allantois** is an embryonic structure that contributes to the formation of the **urachus and urinary bladder**. - "Patent allantois" is not standard clinical terminology; the correct term for persistent allantois-bladder-umbilical connection is **patent urachus**. - The allantois itself is part of the developmental pathway leading to the urachus. *Mid gut loop hernia* - An **omphalocele** is a type of abdominal wall defect where **midgut herniates through the umbilical ring**, covered by a membrane (peritoneum and amnion). - Presents as a **large, membrane-covered sac containing abdominal organs** (intestines, liver) at the umbilicus, apparent at birth. - This is a **structural defect**, not a failure of duct obliteration, and does not involve patent urachus.

Q: All of the following structures develop from the structure marked as $X$ in a male fetus except:

Prostate. ***Prostate*** - The **prostate gland** develops from outgrowths of the **urogenital sinus**, specifically the pelvic portion, and not from the mesonephric (Wolffian) duct. - Its development is influenced by **dihydrotestosterone (DHT)**. *Seminal vesicle* - The **seminal vesicles** develop as an outgrowth from the **mesonephric (Wolffian) duct**, specifically the caudal end, near its junction with the urogenital sinus. - This structure (marked as X) represents the mesonephric duct. *Epididymis* - The **epididymis** develops from the cranial and middle portions of the **mesonephric (Wolffian) duct (X)**. - In males, this duct persists and forms the efferent ductules, epididymis, vas deferens, and seminal vesicles. *Ductus deferens* - The **ductus deferens** (vas deferens) develops from the persistent portion of the **mesonephric (Wolffian) duct (X)**, distal to the epididymis. - It functions in transporting sperm from the epididymis to the ejaculatory duct.

Q: The testis reaches the point marked $X$ at which month of gestation? (Recent NEET Pattern 2016-17)

7th month. ***7th month*** - The diagram shows the **testis** descending through the **inguinal canal** into the scrotum. - Testicular descent typically occurs during the **seventh month** of gestation, guided by the **gubernaculum**. *5th month* - By the fifth month, the testes have typically descended to the **deep inguinal ring** but have not yet entered the inguinal canal. - This stage precedes the point marked X, indicating an earlier phase of descent. *6th month* - During the sixth month, the testes are usually found within the **inguinal canal**, but not yet nearing its exit into the scrotum. - The point X represents the testis having passed through the inguinal canal, which occurs later. *8th month* - By the eighth month, the testes are typically **fully descended into the scrotum**. - The image depicts the testis at the exit of the inguinal canal, signifying the completion of descent rather than full scrotal positioning.

Q: The part of the collecting duct system marked in blue develops from:

Ureteric bud. ***Ureteric bud*** - The blue-marked structure in the image is the **collecting tubule**, which is part of the **collecting duct system** of the kidney. - The entire collecting duct system, including the collecting tubules, collecting ducts, minor and major calyces, renal pelvis, and ureter, develops from the **ureteric bud**. *Metanephric blastema* - The **metanephric blastema** (also known as metanephric mesenchyme) develops into the **nephron** itself, which includes the renal corpuscle (glomerulus and Bowman's capsule), proximal convoluted tubule, loop of Henle, and distal convoluted tubule. - It does not give rise to the collecting system. *Allantois* - The **allantois** is an extraembryonic membrane that contributes to the formation of the **urachus** and ultimately the median umbilical ligament and the urinary bladder. - It is not directly involved in the formation of the renal tubules or collecting system. *Pronephros* - The **pronephros** is the earliest and most rudimentary excretory organ in vertebrate embryonic development, which **regresses completely** in humans. - It does not contribute to the definitive kidney structures in humans.

Q: Which of the following develops from the part shown as X in the development of heart?

Truncus arteriosus. ***Truncus arteriosus*** - The image shows the primitive heart tube, and **X represents the truncus arteriosus**, which is the **most cranial (superior) part** of the developing heart tube - The truncus arteriosus is a single large arterial trunk that undergoes septation to form the **ascending aorta** and the **pulmonary trunk (pulmonary artery)** - During development, **spiral aorticopulmonary septum** divides the truncus arteriosus into the two great vessels - This occurs during weeks 5-8 of embryonic development *Ductus arteriosus* - The ductus arteriosus is a **fetal blood vessel** that connects the pulmonary artery to the descending aorta, allowing blood to bypass the non-functional fetal lungs - It is **not a segment of the primitive heart tube** but develops separately as part of the 6th pharyngeal arch artery system - It forms after the truncus arteriosus has already divided into the aorta and pulmonary trunk *Crista terminalis* - The crista terminalis is a **ridge in the adult right atrium** that separates the smooth-walled sinus venarum posteriorly from the rough-walled pectinate muscles anteriorly - It is a **morphological feature of the mature heart** that develops from the junction between the sinus venosus and primitive atrium - It does not correspond to the cranial portion of the primitive heart tube (which is the truncus arteriosus) *Cavo-tricuspid isthmus* - The cavo-tricuspid isthmus is a region of the **adult right atrium** located between the inferior vena cava orifice and the tricuspid valve annulus - It is an important **anatomical landmark in cardiac electrophysiology** (target for cavotricuspid isthmus-dependent atrial flutter ablation) - It is a feature of the developed heart and does not represent any segment of the early primitive heart tube

Q: The diagram given below depicts the various parts from which the diaphragm develops. Defect in which part most commonly leads to congenital diaphragmatic hernia? (AIIMS May 2016)

A. ***A*** - A indicates the **pleuroperitoneal membranes**, which are posterior and lateral structures that form a significant portion of the diaphragm. - Failure of these membranes to fuse with other diaphragmatic components, particularly on the left side, leads to a **Bochdalek hernia**, the most common type of congenital diaphragmatic hernia. *B* - B represents the **septum transversum**, which forms the central tendon of the diaphragm and contributes to the anterior portion. - Defects in the septum transversum can lead to **Morgagni hernias**, which are less common than Bochdalek hernias and are typically anterior and retrosternal. *C* - C indicates the **mesentery of the esophagus**, which forms the crura of the diaphragm. - Defects in this region are rare causes of diaphragmatic hernia and usually involve the posterior medial aspect. *D* - D points to the **muscular ingrowth from the body wall**, which forms the peripheral musculature of the diaphragm. - While essential for complete diaphragm formation, isolated defects in this part are less commonly implicated as the primary cause of major congenital diaphragmatic hernias compared to the pleuroperitoneal membranes.

Q: Portal vein develops from which of these structures? (AIIMS May 2016)

B. ***B*** - In this diagram illustrating embryonic vein development, the structure labeled **B** represents the **right vitelline vein**, which contributes significantly to the formation of the portal vein system. - The **portal vein** is formed from the anastomosing network of the vitelline veins around the duodenum, with the right vitelline vein becoming its main stem. *A* - The structure labeled **A** represents the **anterior cardinal veins**, which contribute to structures like the superior vena cava, not the portal vein. - These veins drain the cranial part of the embryo. *C* - The structure labeled **C** represents the **left vitelline vein** which, in later development, largely **regresses** or contributes to smaller veins, unlike the right vitelline vein shown at B. - While part of the vitelline system, its contribution to the definitive portal vein is minor compared to the right vitelline vein. *D* - The structure labeled **D** represents the **umbilical veins**, which carry oxygenated blood and nutrients from the placenta to the fetus. - Postnatally, the umbilical veins obliterate to form the **ligamentum teres hepatis** and the **ligamentum venosum**, and do not form the portal vein.

Question 1

The condition shown in the image below is?

Accepted Answer

Patent urachus

Answer

Patent vitello-intestinal duct

Answer

Patent allantois

Answer

Mid gut loop hernia

Question 2

All of the following structures develop from the structure marked as $X$ in a male fetus except:

Accepted Answer

Prostate

Answer

Seminal vesicle

Answer

Epididymis

Answer

Ductus deferens

Question 3

The testis reaches the point marked $X$ at which month of gestation? (Recent NEET Pattern 2016-17)

Accepted Answer

7th month

Answer

5th month

Answer

6th month

Answer

8th month

Question 4

The part of the collecting duct system marked in blue develops from:

Accepted Answer

Ureteric bud

Answer

Metanephric blastema

Answer

Allantois

Answer

Pronephros

Question 5

Which of the following develops from the part shown as X in the development of heart?

Accepted Answer

Truncus arteriosus

Answer

Ductus arteriosus

Answer

Crista terminalis

Answer

Cavo-tricuspid isthmus

Question 6

Which is correct about the diagram shown?

Accepted Answer

A= Allantois, B= Connecting stalk, C= Yolk Sac, D= Chorion with villi

Answer

A= Amnion, B= Connecting stalk, C= Yolk Sac, D= Intraembryonic mesoderm

Answer

A= Amnion, B= Connecting stalk, C= Yolk Sac, D= Extraembryonic Celom

Answer

A= Amnion, B= Connecting stalk, C= Allantois, D= Chorion with villi

Question 7

Which of the following is correct for the image shown below?

Accepted Answer

A= Neural tube, B= Somites, C= Splanchnopleuric intraembryonic mesoderm, D= Notochord

Answer

A= Neural tube, B= Somatopleuric intraembryonic mesoderm, C= Somites, D= Notochord

Answer

A= Neural tube, B= Splanchnopleuric intraembryonic mesoderm, C= Somites, D= Notochord

Answer

A= Neural tube, B= Somites, C= Somatopleuric intraembryonic mesoderm, D= Notochord

Question 8

As shown in the figure, abnormal subclavian artery develops as a result of: (AIIMS May 2016)

Accepted Answer

Obliteration of B with persistence of A

Answer

Persistence of B

Answer

Persistence of A

Answer

Obliteration of A with persistence of B

Question 9

The diagram given below depicts the various parts from which the diaphragm develops. Defect in which part most commonly leads to congenital diaphragmatic hernia? (AIIMS May 2016)

Accepted Answer

A

Answer

B

Answer

C

Answer

D

Question 10

Portal vein develops from which of these structures? (AIIMS May 2016)

Accepted Answer

B

Answer

A

Answer

C

Answer

D

Embryology and Development — MCQs

Embryology and Development — MCQs

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