Embryology and Development Practice Questions

Q: Which is wrong about the image given below?

Dorsal mesentery degenerates. ***Dorsal mesentery degenerates*** - The **dorsal mesentery** persists and develops into various mesenteries supporting the abdominal organs (e.g., mesentery proper, transverse mesocolon, sigmoid mesocolon). It does not degenerate. - The **ventral mesentery degenerates** in areas due to the rotation of the gut and fusion processes, but the dorsal mesentery generally remains. *Foregut meets the stomodeum at bucco-pharyngeal membrane which ruptures at 4 weeks* - The **buccopharyngeal membrane separates the foregut from the stomodeum** (primitive mouth). - This membrane normally **ruptures around the 4th week** of development to establish communication between the oral cavity and the foregut. *Hindgut meets the proctodeum which ruptures at 8th week* - The **hindgut meets the proctodeum** (primitive anal pit) at the **cloacal membrane**. - This **cloacal membrane ruptures around the 7th or 8th week** of development, forming the anal opening. *Lining epithelium of gut is endodermal* - The **endoderm is the primary germ layer** that forms the lining epithelium of the entire gastrointestinal tract. - This includes the epithelium of the esophagus, stomach, intestines, and associated glands.

Q: The condition shown below is due to ?

Patent vitello-intestinal duct. ***Patent vitello-intestinal duct*** - The image shows a **patent vitello-intestinal duct** (also called patent omphalomesenteric duct or patent vitelline duct), which is a persistent connection between the **ileum** and the **umbilicus**. - This represents failure of the vitelline duct to obliterate during the 5th-9th week of embryonic development. - Clinically presents as **umbilical fistula** with discharge of intestinal contents, **umbilical polyp**, or **umbilical sinus**. - The persistent duct connects the intestine to the umbilicus, which is visible in the image. *Patent urachus* - A patent urachus is a persistent connection between the **bladder** and the **umbilicus**, resulting from failure of obliteration of the allantois. - Presents with **urine leakage** from the umbilicus, not intestinal contents. - This is a urological anomaly, not associated with intestinal connection to the umbilicus. *Patent allantois* - The allantois is an embryonic structure that normally becomes the **urachus** connecting bladder to umbilicus. - Patent allantois is essentially the same as **patent urachus**. - Would present with urinary discharge, not the intestinal connection shown in the image. *Midgut loop hernia* - Midgut loop herniation is a **normal physiological process** occurring at 6-10 weeks of gestation where midgut herniates into the umbilical cord and then returns. - Failure of this to reduce leads to **omphalocele** (herniation of abdominal contents covered by peritoneum and amnion). - This is different from a patent vitello-intestinal duct, which is a **tubular connection** between ileum and umbilicus, not a herniation of abdominal organs.

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

Question 1

Which is correct sequence about the blood supply of the primitive gut?

Accepted Answer

Foregut= Celiac trunk, Midgut= Superior mesenteric artery, Hindgut= inferior mesenteric artery

Answer

Foregut= Superior mesenteric artery, Midgut= Celiac trunk, Hindgut= inferior mesenteric artery

Answer

Foregut= Celiac trunk, Midgut= Superior mesenteric artery, Hindgut= ileocolic artery

Answer

Foregut= Celiac trunk, Midgut= Inferior mesenteric artery, Hindgut= inferior mesenteric artery

Question 2

Which is wrong about the image given below?

Accepted Answer

Dorsal mesentery degenerates

Answer

Foregut meets the stomodeum at bucco-pharyngeal membrane which ruptures at 4 weeks

Answer

Hindgut meets the proctodeum which ruptures at 8th week

Answer

Lining epithelium of gut is endodermal

Question 3

The condition shown below is due to ?

Accepted Answer

Patent vitello-intestinal duct

Answer

Patent urachus

Answer

Patent allantois

Answer

Midgut loop hernia

Question 4

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 5

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 6

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 7

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

Accepted Answer

Ureteric bud

Answer

Metanephric blastema

Answer

Allantois

Answer

Pronephros

Question 8

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 9

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 10

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

Embryology and Development — MCQs

Embryology and Development — MCQs

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