Chapter: Embryology; Topic: Development of Venous System; Subtopic: Formation of Inferior Vena Cava (IVC)
Keyword Definitions:
Vitelline veins: Paired embryonic veins that contribute to hepatic vasculature and the hepatic segment of the IVC.
Cardinal veins: Early embryonic systemic veins (anterior and posterior) largely replaced but contributing to parts of SVC and some venous channels.
Subcardinal veins: Paired veins that form portions of the renal and prerenal IVC segments and renal veins.
Supracardinal veins: Paired veins that form the postrenal (infrarenal) IVC and parts of the azygos/hemiazygos system.
Intercardinal anastomoses: Connections between cardinal veins; some form venous channels (azygos system) but not major segments of IVC.
1) Lead Question – 2016
All of the following help in formation of IVC except -
A) The posterior intercardinal anastomosis
B) Terminal portion of right vitelline vein
C) Segment of right cardinal vein
D) Subcardinal sinus
Answer: A) The posterior intercardinal anastomosis
Explanation: The IVC forms from a complex cranial–caudal series of embryonic veins: the hepatic segment from the right vitelline vein (terminal portion), the prerenal/renal segments from subcardinal veins and their anastomoses (including subcardinal–supracardinal connections), and the postrenal (infrarenal) part from the right supracardinal vein. While remnants of cardinal system contribute small channels, the posterior intercardinal anastomosis specifically helps form portions of the azygos/hemiazygos or transient connections rather than a principal IVC segment. Therefore the posterior intercardinal anastomosis (A) is **not** a contributor to the main IVC formation.
2) Which embryonic vein primarily contributes to the hepatic segment of the IVC?
A) Left vitelline vein
B) Right vitelline vein
C) Right supracardinal vein
D) Left subcardinal vein
Answer: B) Right vitelline vein
Explanation: The hepatic segment of the inferior vena cava originates from the terminal portion of the right vitelline vein after extensive remodeling within the developing liver. Vitelline veins supply the hepatic sinusoids; the right-sided vitelline structures are preserved to form the hepatic IVC and hepatic veins. Supracardinal and subcardinal veins form more caudal IVC segments; the left vitelline and left-sided subcardinal structures largely regress. Thus, the right vitelline vein (B) is the principal embryologic contributor to the hepatic segment of the adult IVC.
3) The infrarenal (postrenal) segment of the IVC is derived from–
A) Left supracardinal vein
B) Right supracardinal vein
C) Right posterior cardinal vein
D) Left subcardinal vein
Answer: B) Right supracardinal vein
Explanation: The infrarenal (postrenal) portion of IVC is derived from the right supracardinal vein. During embryogenesis the supracardinal system replaces posterior cardinal veins dorsally; the right supracardinal persists as the lower IVC while the left supracardinal mostly regresses. The posterior cardinal veins largely disappear or contribute minimally. Subcardinal veins form the prerenal/renal region rather than the infrarenal segment. Therefore, the correct embryologic source for postrenal IVC is the right supracardinal vein (B).
4) The renal segment of IVC results from anastomosis between–
A) Vitelline and posterior cardinal veins
B) Subcardinal and supracardinal veins
C) Anterior and posterior cardinal veins
D) Left and right vitelline veins
Answer: B) Subcardinal and supracardinal veins
Explanation: The renal segment of the IVC is formed by complex anastomoses between the subcardinal and supracardinal veins, specifically the subcardinal–supracardinal connection that becomes the renal portion. This anastomosis allows drainage of renal veins into the IVC. Vitelline veins form the hepatic region, while cardinal veins are earlier dorsal venous channels largely replaced. Thus, B is correct: the subcardinal–supracardinal anastomosis is essential for the renal segment development.
5) Failure of the right subcardinal system to connect properly with the hepatic (vitelline) segment would most likely cause–
A) Absent hepatic veins
B) Double IVC or abnormal left-sided IVC
C) Pulmonary venous return defect
D) Persistent left SVC
Answer: B) Double IVC or abnormal left-sided IVC
Explanation: Errors in regression or persistence of supracardinal/subcardinal channels can produce anomalous patterns, such as a double IVC (persistence of left supracardinal) or left-sided IVC when right-sided segments regress. If right subcardinal–vitelline connections fail, alternate pathways may persist leading to duplicated or transposed IVC. Pulmonary venous return and SVC anomalies involve different embryologic sources. Therefore, venous malformations like double or left-sided IVC (B) are the expected consequences of faulty subcardinal–vitelline integration.
6) Which embryonic venous channel largely regresses and is replaced by supracardinal veins dorsally?
A) Anterior cardinal veins
B) Posterior cardinal veins
C) Vitelline veins
D) Umbilical veins
Answer: B) Posterior cardinal veins
Explanation: Posterior cardinal veins are early dorsal embryonic channels that largely regress as the supracardinal system develops dorsally and takes over the role of posterior body wall drainage. Portions of posterior cardinals contribute transiently or to small remnants, but the supracardinal veins form the definitive infrarenal IVC and azygos system. Vitelline veins persist in hepatic region; anterior cardinals form SVC. Thus, posterior cardinal veins (B) are principally replaced by supracardinal vessels.
7) The hepatic veins drain into the IVC segment derived from–
A) Right supracardinal vein
B) Right vitelline vein (terminal portion)
C) Left subcardinal vein
D) Posterior cardinal vein
Answer: B) Right vitelline vein (terminal portion)
Explanation: Hepatic veins drain into the hepatic segment of the IVC, which is derived from the terminal portion of the right vitelline vein incorporated into the liver sinusoids. This vitelline-derived segment connects the liver venous outflow to the rest of the IVC. Supracardinal/subcardinal regions form caudal segments; posterior cardinals largely regress. Therefore, the correct embryologic origin for the hepatic IVC receiving hepatic veins is the terminal right vitelline vein (B).
8) Persistent left-sided supracardinal vein results in–
A) Retroaortic left renal vein or duplicated IVC
B) Agenesis of IVC
C) Persistent ductus venosus
D) Interrupted aortic arch
Answer: A) Retroaortic left renal vein or duplicated IVC
Explanation: Persistence of left supracardinal structures can produce a duplicated IVC (with both right and left infrarenal IVCs) or a retroaortic left renal vein if the left-sided channel persists abnormally. Complete agenesis of IVC is rare and involves other failures. Ductus venosus and aortic arch defects have different embryological bases. Hence, A correctly describes typical anomalies arising from persistence of left supracardinal venous channels.
9) The terminal hepatic segment of IVC is lost in which anomaly leading to azygos continuation of IVC?
A) Failure of right vitelline formation
B) Failure of right subcardinal–hepatic anastomosis (hepatic segment absent)
C) Persistence of posterior cardinal veins
D) Duplication of ureteric bud
Answer: B) Failure of right subcardinal–hepatic anastomosis (hepatic segment absent)
Explanation: Azygos continuation of the IVC occurs when the hepatic segment (terminal connection to the heart) fails to form—commonly due to absent right subcardinal–hepatic anastomosis—forcing systemic venous return from the lower body to reach the SVC via the azygos system (supracardinal remnants). This anomaly is not due to vitelline failure per se; it reflects disrupted subcardinal–vitelline integration. Therefore B accurately describes the embryologic defect producing azygos continuation of IVC.
10) Which embryonic vein contributes to formation of the renal veins?
A) Vitelline veins
B) Subcardinal veins
C) Anterior cardinal veins
D) Umbilical veins
Answer: B) Subcardinal veins
Explanation: The subcardinal veins develop medial to the mesonephros and form important components of the prerenal and renal IVC segments; they also give rise to the renal veins. Subcardinal–supracardinal anastomoses position the renal veins into the IVC. Vitelline veins contribute to hepatic veins, anterior cardinals to SVC, and umbilical veins to the fetal placental circuit. Thus, B is correct: subcardinal veins are vital for renal venous development.
11) Clinically, a duplicated IVC results from persistence of which embryologic structure on the left side?
A) Left vitelline vein
B) Left supracardinal vein
C) Left subcardinal vein only
D) Posterior intercardinal anastomosis
Answer: B) Left supracardinal vein
Explanation: A duplicated IVC typically arises when the left supracardinal vein fails to regress while the right supracardinal also persists, producing two infrarenal venous channels (right and left IVC). This venous duplication may be asymptomatic but is important surgically and radiologically. Left supracardinal persistence explains the anomaly more specifically than subcardinal or vitelline persistence. Posterior intercardinal anastomosis is not responsible for a true duplicated IVC. Therefore, B is the correct embryologic cause of duplicated IVC.
Chapter: Embryology; Topic: Development of Kidney; Subtopic: Origin of Metanephric Structures
Keyword Definitions:
Metanephros: Definitive kidney appearing in the 5th week; forms nephron structures (kidney parenchyma).
Ureteric Bud: Outgrowth from mesonephric duct forming collecting system (ureter, pelvis, calyces, collecting ducts).
Mesonephros: Temporary embryonic kidney functioning briefly before degeneration.
Paramesonephric Duct: Müllerian duct forming female reproductive tract structures.
Metanephric Blastema: Mesenchyme induced by ureteric bud to form nephrons.
1) Lead Question – 2016
Kidney parenchyma is derived from–
A) Ureteric bud
B) Mesonephros
C) Metanephros
D) Paramesonephros
Answer: C) Metanephros
Explanation: The kidney parenchyma, including nephrons (glomeruli, proximal tubules, loops of Henle, and distal tubules), is derived from the metanephros, which develops from metanephric mesenchyme. The ureteric bud forms the collecting system only. The mesonephros functions transiently in early fetal life, while paramesonephric ducts give rise to female reproductive organs. Thus, the definitive renal tissue forming the functional filtration units originates from the metanephros, making option C the correct answer.
2) The collecting ducts of the kidney are derived from–
A) Metanephric blastema
B) Mesonephric duct
C) Ureteric bud
D) Paramesonephric duct
Answer: C) Ureteric bud
Explanation: The ureteric bud gives rise to ureter, renal pelvis, major and minor calyces, and collecting ducts. Metanephric blastema forms nephron components. The mesonephric duct forms male reproductive structures, and paramesonephric duct forms female reproductive organs. Thus, C is correct, reflecting the branching morphogenesis essential for forming the collecting system.
3) A newborn with renal agenesis likely has developmental failure of the–
A) Metanephric mesenchyme
B) Paramesonephric duct
C) Cloacal membrane
D) Surface ectoderm
Answer: A) Metanephric mesenchyme
Explanation: Renal agenesis occurs when the ureteric bud fails to induce the metanephric mesenchyme, preventing nephron formation. Paramesonephric ducts form reproductive organs; cloacal membrane forms urogenital and anal openings. Surface ectoderm does not contribute to kidney development. Therefore, A is correct, representing a failure in inductive interaction between ureteric bud and metanephric tissue.
4) Glomeruli develop from the–
A) Ureteric bud
B) Metanephric blastema
C) Mesonephric duct
D) Neural crest
Answer: B) Metanephric blastema
Explanation: Glomeruli originate from metanephric mesenchyme, which forms all nephron components except the collecting system. The ureteric bud forms collecting ducts, while mesonephric duct and neural crest are unrelated to nephron formation. Thus, B is correct, reflecting the essential role of metanephric blastema in nephron development.
5) In Potter sequence, the most direct cause of reduced amniotic fluid is–
A) Defective ureteric bud branching
B) Absent metanephric blastema induction
C) Paramesonephric duct regression
D) Urachal anomaly
Answer: B) Absent metanephric blastema induction
Explanation: Renal agenesis results from failed induction of metanephric blastema by the ureteric bud, leading to absent urine production and oligohydramnios (Potter sequence). Paramesonephric structures affect reproductive tract only; urachal anomalies affect bladder apex. Thus, B is correct, identifying the key embryologic defect behind Potter features.
6) Which structure induces metanephric mesenchyme to form nephrons?
A) Paramesonephros
B) Ureteric bud
C) Cloacal membrane
D) Cardinal veins
Answer: B) Ureteric bud
Explanation: Reciprocal induction between ureteric bud and metanephric mesenchyme is essential: the bud stimulates nephron formation, and mesenchyme induces bud branching. Paramesonephros and cloacal membrane do not contribute. Cardinal veins belong to venous development. Thus, B is correct, highlighting the critical embryologic signaling pathway.
7) Mesonephric ducts persist in males to form–
A) Epididymis, vas deferens
B) Collecting ducts
C) Nephrons
D) Urethra
Answer: A) Epididymis, vas deferens
Explanation: Mesonephric (Wolffian) ducts form epididymis, vas deferens, seminal vesicles, and ejaculatory ducts in males. They do not contribute to nephron or collecting system development. Thus, A is correct, illustrating their role in male reproductive anatomy.
8) Which fetal structure gives rise to major and minor renal calyces?
A) Ureteric bud
B) Metanephric mesenchyme
C) Mesonephros
D) Intermediate mesoderm
Answer: A) Ureteric bud
Explanation: Branching of the ureteric bud forms renal pelvis, major calyces, minor calyces, and collecting ducts. Metanephric mesenchyme forms nephron units. Mesonephros degenerates. While intermediate mesoderm gives rise to kidney precursors, the direct source is the ureteric bud. Thus, A is correct.
9) A neonate shows duplex collecting system. This most likely results from–
A) Early splitting of the ureteric bud
B) Duplicated metanephric mesenchyme
C) Paramesonephric duct fusion
D) Absent mesonephric duct
Answer: A) Early splitting of the ureteric bud
Explanation: Duplex kidneys result when the ureteric bud divides early, creating two collecting systems. Metanephric mesenchyme simply responds to bud branching; paramesonephric ducts form reproductive organs; mesonephric duct absence causes renal agenesis, not duplication. Thus, A is correct.
10) Which embryonic derivative forms the distal convoluted tubule?
A) Ureteric bud
B) Metanephric blastema
C) Mesonephric duct
D) Surface ectoderm
Answer: B) Metanephric blastema
Explanation: All nephron tubules—including proximal, loop of Henle, and distal tubules—come from metanephric blastema. The ureteric bud forms only collecting ducts. Surface ectoderm and mesonephric duct are unrelated. Thus, B is correct.
11) A fetal ultrasound shows bilateral renal cysts with preserved collecting system. This suggests a defect in–
A) Metanephric blastema differentiation
B) Ureteric bud formation
C) Cloacal partitioning
D) Paramesonephric ducts
Answer: A) Metanephric blastema differentiation
Explanation: Polycystic kidney diseases often involve defective nephron development from metanephric mesenchyme, while collecting ducts remain intact. Ureteric bud defects cause absent collecting systems. Cloacal defects affect bladder/rectum; paramesonephric ducts affect reproductive tract. Thus, A is correct, indicating nephron-level developmental pathology.
Chapter: Embryology; Topic: Pharyngeal (Branchial) Apparatus; Subtopic: Nerve Derivatives of Branchial Arches
Keyword Definitions:
Branchial Arches: Mesoderm–neural crest structures forming skeletal, muscular, and neural elements of head and neck.
Second Branchial Arch (Hyoid Arch): Forms muscles of facial expression, stapes, styloid process, and is supplied by facial nerve.
Facial Nerve (VII): Nerve of the second arch, supplying muscles of facial expression.
First Branchial Arch: Forms muscles of mastication; nerve is mandibular division of trigeminal (V3).
Third Branchial Arch: Gives stylopharyngeus muscle; nerve is glossopharyngeal (IX).
1) Lead Question – 2016
Facial nerve is a derivative of which of the following branchial arch?
A) First arch
B) Second arch
C) Third arch
D) Fourth arch
Answer: B) Second arch
Explanation: The facial nerve (cranial nerve VII) is the nerve of the second branchial (hyoid) arch. This arch forms muscles of facial expression, stapedius, stylohyoid, and posterior belly of digastric. The first arch gives rise to muscles of mastication supplied by V3, the third arch is supplied by glossopharyngeal nerve (IX), and the fourth arch receives vagus nerve branches. Thus, B is correct. Recognizing nerve–arch associations is crucial in understanding congenital anomalies, branchial defects, and cranial nerve palsies affecting facial muscle function.
2) The muscle of facial expression develops from the–
A) First arch
B) Second arch
C) Third arch
D) Fourth arch
Answer: B) Second arch
Explanation: Muscles of facial expression (orbicularis oculi, orbicularis oris, buccinator, etc.) originate from the mesoderm of the second branchial arch, innervated by facial nerve (VII). The first arch forms muscles of mastication, the third gives stylopharyngeus, and the fourth gives pharyngeal constrictors. Hence, B is correct and highlights the strong link between arch derivatives and cranial nerve supply.
3) A newborn presents with facial paralysis due to absent facial nerve. Which skeletal structure is also likely affected?
A) Meckel’s cartilage
B) Stapes
C) Thyroid cartilage
D) Greater horn of hyoid
Answer: B) Stapes
Explanation: The stapes is derived from Reichert’s cartilage of the second arch, the same arch supplying facial nerve. Meckel’s cartilage (first arch) forms malleus and incus; thyroid cartilage derives from fourth arch; greater horn of hyoid from third arch. Thus, B is correct. Damage to second arch derivatives frequently co-occurs with facial nerve abnormalities.
4) The second branchial arch contributes to which muscle?
A) Tensor tympani
B) Stapedius
C) Stylopharyngeus
D) Cricothyroid
Answer: B) Stapedius
Explanation: Stapedius is a derivative of the second arch and is supplied by facial nerve. Tensor tympani comes from first arch; stylopharyngeus from third; cricothyroid from fourth arch. Thus, B is correct, reinforcing the facial nerve’s association with second arch musculature.
5) Which cranial nerve supplies derivatives of the third arch?
A) V3
B) VII
C) IX
D) X
Answer: C) IX
Explanation: Glossopharyngeal nerve (IX) supplies stylopharyngeus, the only muscle derived from the third arch. V3 supplies first arch, VII supplies second arch, and X supplies fourth and sixth arches. Thus, C is correct, demonstrating the specific nerve–arch relationships.
6) Which of the following cartilaginous structures is derived from the second arch?
A) Malleus
B) Styloid process
C) Thyroid cartilage
D) Cricoid cartilage
Answer: B) Styloid process
Explanation: The styloid process arises from Reichert’s cartilage of the second arch. Malleus is first arch; thyroid and cricoid cartilages arise from fourth and sixth arches. Thus, B is correct. This supports identifying skeletal derivatives specific to each branchial arch.
7) A neonate with dysphagia and absent gag reflex likely has abnormal development of which arch?
A) First
B) Second
C) Third
D) Fourth
Answer: C) Third
Explanation: The glossopharyngeal nerve (IX), nerve of the third arch, mediates gag reflex and supplies stylopharyngeus, essential for swallowing. First and second arch defects impair mastication and facial expression, respectively. Fourth arch defects affect pharyngeal constrictors and laryngeal muscles. Thus, C is correct, as third arch anomalies present with pharyngeal dysfunction.
8) Posterior belly of digastric muscle is derived from–
A) First arch
B) Second arch
C) Third arch
D) Fourth arch
Answer: B) Second arch
Explanation: The posterior belly of digastric originates from the second arch, supplied by facial nerve. The anterior belly is from the first arch. Third and fourth arches do not contribute to digastric muscle. Thus, B is correct, illustrating dual arch origins of this muscle.
9) The recurrent laryngeal nerve is associated with which branchial arch?
A) First
B) Second
C) Third
D) Sixth
Answer: D) Sixth
Explanation: The recurrent laryngeal nerve supplies derivatives of the sixth arch, including intrinsic laryngeal muscles except cricothyroid. First arch is V3, second arch is VII, third is IX. Thus, D is correct, showing the neural association with laryngeal development.
10) Which artery is derived from the second arch?
A) Maxillary artery
B) Stapedial artery
C) Common carotid
D) Arch of aorta
Answer: B) Stapedial artery
Explanation: The stapedial artery transiently arises from the second arch before regressing. Maxillary artery is first arch; common carotid comes from third; aortic arch from fourth. Thus, B is correct, describing vascular derivatives of the second arch.
11) A child presents with facial muscle weakness and malformed auricle. The defect likely involves–
A) First arch
B) Second arch
C) Third arch
D) Sixth arch
Answer: B) Second arch
Explanation: Second arch abnormalities lead to facial nerve dysfunction and external ear deformities because auricular hillocks arise from first and second arches. Third and sixth arches do not contribute directly to facial muscles or auricle development. Thus, B is correct, as second arch maldevelopment best explains both clinical findings.
Chapter: Cell Biology; Topic: Meiosis; Subtopic: Stages of Meiotic Prophase I
Keyword Definitions:
Meiosis: A specialized cell division producing haploid gametes from diploid germ cells.
Prophase I: Longest meiotic phase with distinct substages—leptotene, zygotene, pachytene, diplotene, diakinesis.
Leptotene: Chromosomes begin to condense into long thin threads.
Pachytene: Homologous chromosomes fully synapse; crossing over occurs.
Crossing Over: Exchange of genetic material during pachytene contributing to genetic diversity.
1) Lead Question – 2016
Leptotene and pachytene are stages of which phase of meiosis–
A) Prophase I
B) Metaphase I
C) Anaphase II
D) Telophase II
Answer: A) Prophase I
Explanation: Prophase I is the most complex phase of meiosis and is subdivided into leptotene, zygotene, pachytene, diplotene, and diakinesis. Leptotene marks early chromatin condensation, while pachytene involves synapsis of homologous chromosomes and crossing over. These events do not occur in metaphase I, anaphase II, or telophase II. Therefore, A is correct. Identifying these substages is essential in understanding the chromosomal behavior leading to genetic recombination and proper segregation during gametogenesis.
2) Crossing over occurs during which stage of meiosis?
A) Leptotene
B) Pachytene
C) Diakinesis
D) Metaphase I
Answer: B) Pachytene
Explanation: Pachytene is the stage in prophase I where homologous chromosomes are fully synapsed and crossing over occurs through chiasmata formation. Leptotene shows partial chromatin condensation; diakinesis involves terminalization of chiasmata; metaphase I aligns bivalents at the equator. Thus, B is the correct answer, underscoring the significance of pachytene in generating genetic variability.
3) A genetic disorder involving defective synaptonemal complex formation would most directly affect–
A) Zygotene
B) Anaphase I
C) Anaphase II
D) Telophase I
Answer: A) Zygotene
Explanation: During zygotene, homologous chromosomes pair through the synaptonemal complex. Defects in this complex prevent proper synapsis, leading to meiotic arrest or aneuploidy. Anaphase and telophase stages involve chromosome segregation and do not require synaptonemal formation. Therefore, A is correct, highlighting the essential role of zygotene in homolog pairing during meiosis.
4) Terminalization of chiasmata occurs in–
A) Diplotene
B) Zygotene
C) Pachytene
D) Leptotene
Answer: A) Diplotene
Explanation: Diplotene follows pachytene and is characterized by partial separation of homologs as chiasmata move toward the chromosome ends (terminalization). Zygotene involves synapsis; pachytene involves crossing over; leptotene shows early condensation. Thus, A is correct. Diplotene is also prolonged in oocytes, remaining arrested until ovulation, making this stage clinically significant.
5) Oocytes in a newborn female are arrested in which stage?
A) Pachytene
B) Diplotene
C) Metaphase II
D) Anaphase I
Answer: B) Diplotene
Explanation: Primary oocytes arrest in prophase I at the diplotene (dictyotene) stage until puberty. Pachytene and earlier phases are completed embryonically. Metaphase II occurs after ovulation. Thus, B is correct. Understanding this arrest is key in reproductive physiology and disorders involving oocyte maturation.
6) A patient with infertility shows failure of homologous chromosomes to separate in meiosis I. This is termed–
A) Non-disjunction
B) Aneuploidy correction
C) Synapsis
D) Terminalization
Answer: A) Non-disjunction
Explanation: Non-disjunction is the failure of homologous chromosomes to separate during anaphase I or sister chromatids in anaphase II, leading to aneuploid gametes. Synapsis and terminalization occur earlier in prophase I. Thus, A is correct. Non-disjunction underlies disorders such as Down, Edwards, and Patau syndromes.
7) Synapsis occurs during–
A) Diplotene
B) Zygotene
C) Anaphase I
D) Telophase II
Answer: B) Zygotene
Explanation: Zygotene is defined by the pairing (synapsis) of homologous chromosomes through the synaptonemal complex. Diplotene shows separation, while anaphase and telophase involve chromatid movement and nuclear reformation. Thus, B is correct, highlighting critical initial alignment of homologs in meiosis.
8) Which stage immediately follows pachytene?
A) Leptotene
B) Diplotene
C) Zygotene
D) Diakinesis
Answer: B) Diplotene
Explanation: The sequence of prophase I is leptotene → zygotene → pachytene → diplotene → diakinesis. Thus, diplotene follows pachytene. This distinguishes the progressive structural changes in chromosome morphology essential for successful meiosis. Therefore, B is correct.
9) A woman undergoing assisted reproduction has secondary oocytes arrested in–
A) Prophase I
B) Metaphase II
C) Anaphase I
D) Telophase I
Answer: B) Metaphase II
Explanation: Secondary oocytes arrest in metaphase II until fertilization. Prophase I arrest occurs in primary oocytes. Anaphase and telophase follow metaphase only after activation. Hence, B is correct. This arrest mechanism ensures proper timing of meiotic completion during fertilization.
10) Which phase shows maximum chromosomal condensation before meiosis I ends?
A) Zygotene
B) Pachytene
C) Diakinesis
D) Diplotene
Answer: C) Diakinesis
Explanation: Diakinesis marks the final stage of prophase I with maximal condensation of chromosomes, nuclear envelope breakdown, and spindle attachment preparation. Other stages show partial condensation. Thus, C is correct, highlighting the transition into metaphase I.
11) Failure of crossing over during pachytene most likely increases risk of–
A) Balanced translocation
B) Non-disjunction
C) Polyploidy
D) Terminal deletion
Answer: B) Non-disjunction
Explanation: Crossing over stabilizes homolog pairing. Absence of recombination weakens chiasmata, increasing the risk of homologs separating improperly during anaphase I, resulting in non-disjunction. Polyploidy usually arises from cytokinesis failure. Balanced translocations and deletions involve structural chromosomal changes not directly linked to absence of crossing over. Thus, B is correct.
Chapter: Embryology; Topic: Development of Kidney; Subtopic: Abnormalities of Kidney Ascent
Keyword Definitions:
Kidney Ascent: Normal cranial migration of metanephric kidneys from pelvis to lumbar region.
Pelvic Kidney: Kidney that fails to ascend, remaining in the pelvis.
Horseshoe Kidney: Fusion anomaly, usually of lower poles, preventing normal ascent.
Aortic Branch Obstruction: One cause of impaired ascent due to vascular resistance.
Genetic Mutations: Rarely implicated; p53 mutation is not associated with kidney ascent abnormality.
1) Lead Question – 2016
Pelvic kidneys are due to all except?
A) Inability to ascend during fetal life
B) Fusion of the lower poles
C) Being blocked by branches of the aorta
D) p53 mutation
Answer: D) p53 mutation
Explanation: Pelvic kidneys occur when the metanephric kidneys fail to ascend from the pelvis to their normal lumbar position. This can happen due to mechanical obstruction by developing aortic branches or fusion of lower poles, as in horseshoe kidney, which prevents upward migration. Inability to ascend is therefore a common cause. However, p53 mutations are unrelated to kidney ascent and typically involve tumor suppression defects. Therefore, D is correct. Understanding embryologic kidney migration explains congenital anomalies such as ectopic kidney, horseshoe kidney, and aberrant renal vasculature.
2) Horseshoe kidney results from fusion of which renal poles?
A) Upper poles
B) Lower poles
C) Medial poles
D) Lateral poles
Answer: B) Lower poles
Explanation: Horseshoe kidney occurs when the lower poles of the metanephric kidneys fuse during ascent. This fused mass gets trapped under the inferior mesenteric artery, preventing normal migration. Upper pole fusion is extremely rare. Thus, B is correct. The anomaly is usually asymptomatic but may predispose to obstruction or infection.
3) A fused pelvic kidney is discovered in a newborn. The most likely cause is–
A) Failed metanephric induction
B) Arrested ascent of kidney
C) Absent ureteric bud
D) Excessive aortic branching
Answer: B) Arrested ascent of kidney
Explanation: Pelvic fusion anomalies generally arise when kidneys fail to ascend from the pelvis. Metanephric induction failure leads to renal agenesis; absent ureteric bud prevents kidney formation; excessive aortic branching contributes but does not fully explain fusion. Thus, B is correct. Pelvic kidney is often detected incidentally on imaging.
4) The structure that most commonly blocks ascent of a horseshoe kidney is–
A) Renal artery
B) Inferior mesenteric artery
C) Gonadal artery
D) Common iliac vein
Answer: B) Inferior mesenteric artery
Explanation: Horseshoe kidneys become trapped under the inferior mesenteric artery due to lower pole fusion. Renal or gonadal arteries develop later and do not obstruct ascent. Thus, B is correct. This anatomical relationship helps identify the condition on imaging.
5) A child presents with abdominal mass; imaging shows pelvic ectopic kidney. Which complication is more likely?
A) Hypertension
B) Hydronephrosis
C) Hypercalcemia
D) Acute pancreatitis
Answer: B) Hydronephrosis
Explanation: Pelvic kidneys have abnormal orientation and ureteric course, predisposing to obstruction and hydronephrosis. Hypertension is uncommon unless renal artery stenosis occurs. Hypercalcemia and pancreatitis are unrelated. Thus, B is correct, showing developmental malposition can lead to functional impairment.
6) Renal arteries in ectopic kidneys often arise from–
A) Abdominal aorta only
B) Iliac arteries
C) Superior mesenteric artery
D) Celiac trunk
Answer: B) Iliac arteries
Explanation: Pelvic kidneys commonly receive blood supply from iliac arteries because they do not ascend to the lumbar region where normal renal arteries originate. SMA and celiac trunk supply gut organs. Thus, B is correct, explaining atypical vasculature seen in ectopic kidneys.
7) Lack of kidney ascent is usually due to developmental abnormalities in the–
A) Dorsal mesentery
B) Vascular supply
C) Somites
D) Neural crest cells
Answer: B) Vascular supply
Explanation: Vascular changes, especially branches of the aorta, often impede kidney ascent. Somites and neural crest cells do not determine kidney ascent; dorsal mesentery relates to gut rotation. Thus, B is correct, emphasizing vascular influence on renal migration.
8) A patient with horseshoe kidney has increased risk of which disorder?
A) Turner syndrome
B) DiGeorge syndrome
C) Patau syndrome
D) Down syndrome
Answer: A) Turner syndrome
Explanation: Horseshoe kidney is associated with Turner syndrome (45,XO) more commonly than other chromosomal anomalies. Down and Patau syndromes have other systemic anomalies. Thus, A is correct, showing links between renal and chromosomal abnormalities.
9) In renal ectopia, which ureteric feature is commonly seen?
A) Shortened ureter
B) Abnormally long ureter
C) Blind-ending ureter
D) Duplicated ureter
Answer: B) Abnormally long ureter
Explanation: A kidney that fails to ascend remains pelvic, requiring a longer ureter to reach the bladder. Shortened or blind-ending ureters indicate agenesis; duplication arises from ureteric bud anomalies. Thus, B is correct, matching expected anatomical variation in ectopic kidneys.
10) Which embryonic tissue forms the ureteric bud?
A) Intermediate mesoderm
B) Endoderm
C) Ectoderm
D) Splanchnic mesoderm
Answer: A) Intermediate mesoderm
Explanation: The ureteric bud arises from the mesonephric duct, derived from intermediate mesoderm. Endoderm forms bladder epithelium; ectoderm forms skin; splanchnic mesoderm forms cardiac and visceral structures. Thus, A is correct.
11) Persistent pelvic kidney is most easily confused radiologically with–
A) Ovarian mass
B) Splenic cyst
C) Liver hemangioma
D) Pancreatic pseudocyst
Answer: A) Ovarian mass
Explanation: Pelvic kidneys may mimic adnexal masses on ultrasound or CT. Splenic, hepatic, and pancreatic lesions are upper abdominal. Thus, A is correct, emphasizing anatomical overlap in pelvic imaging.
Chapter: Embryology; Topic: Pharyngeal Apparatus; Subtopic: Derivatives of Pharyngeal Pouches
Keyword Definitions:
Pharyngeal Pouches: Endoderm-lined outpouchings that give rise to lymphoid and endocrine structures.
Second Pharyngeal Pouch: Forms epithelial lining of palatine tonsil and tonsillar crypts including crypta magna.
Crypta Magna: Deepest and largest tonsillar crypt within the palatine tonsil.
Third Pouch: Forms inferior parathyroid glands and thymus.
Fourth Pouch: Forms superior parathyroid glands and ultimobranchial body (C-cells).
1) Lead Question – 2016
Crypta magna develops from which pouch?
A) 1st
B) 2nd
C) 3rd
D) 4th
Answer: B) 2nd
Explanation: The palatine tonsil and its epithelial crypts, including the deepest one known as crypta magna, arise from the endoderm of the second pharyngeal pouch. The first pouch forms the auditory tube and middle ear cavity, the third forms thymus and inferior parathyroids, and the fourth forms superior parathyroids and ultimobranchial body. Thus, the correct answer is B. Understanding pouch derivatives is essential for interpreting congenital anomalies of the head and neck.
2) Palatine tonsil epithelium originates from–
A) 1st pouch
B) 2nd pouch
C) 3rd pouch
D) 4th pouch
Answer: B) 2nd pouch
Explanation: Palatine tonsil epithelium is derived from the second pharyngeal pouch. This endodermal lining proliferates to form tonsillar crypts. The first pouch forms Eustachian tube and middle ear. Third and fourth pouches form parathyroids and thymus. Hence, B is correct.
3) A child with recurrent tonsillitis shows enlarged tonsillar crypts. These crypts are derived from which embryologic tissue?
A) Endoderm of 2nd pouch
B) Ectoderm of clefts
C) Neural crest
D) Mesoderm
Answer: A) Endoderm of 2nd pouch
Explanation: Tonsillar crypts, including crypta magna, arise from endoderm of the second pouch. Ectoderm forms external clefts, neural crest forms connective tissues of arches, and mesoderm forms muscles. Thus, A is correct.
4) Which structure is derived from the first pharyngeal pouch?
A) Middle ear cavity
B) Palatine tonsil
C) Thymus
D) Superior parathyroids
Answer: A) Middle ear cavity
Explanation: The first pouch forms the tympanic cavity and auditory tube. The second forms tonsils, the third forms thymus/inferior parathyroids, and the fourth forms superior parathyroids. Thus, A is correct.
5) Thymus develops from which pouch?
A) 1st
B) 2nd
C) 3rd
D) 4th
Answer: C) 3rd
Explanation: The third pouch forms thymus (ventral wing) and inferior parathyroids (dorsal wing). Second pouch forms tonsils; first forms auditory structures; fourth pouch forms superior parathyroids. Thus, C is correct.
6) A newborn with DiGeorge syndrome has abnormal derivatives of which pouch?
A) 1st and 2nd
B) 2nd and 3rd
C) 3rd and 4th
D) Only 4th
Answer: C) 3rd and 4th
Explanation: DiGeorge syndrome involves failure of development of the third and fourth pouches leading to thymic aplasia and parathyroid defects. Tonsils (2nd pouch) remain normal. Thus, C is correct.
7) Ultimobranchial body is derived from which pouch?
A) 1st
B) 2nd
C) 3rd
D) 4th
Answer: D) 4th
Explanation: The ultimobranchial body forms parafollicular (C) cells of thyroid and arises from the fourth pouch. Thus, D is correct.
8) A lesion in superior parathyroid glands suggests abnormality of–
A) 1st pouch
B) 2nd pouch
C) 3rd pouch
D) 4th pouch
Answer: D) 4th
Explanation: Superior parathyroids originate from the fourth pouch. Inferior ones originate from the third pouch. Thus, D is correct.
9) Enlargement of crypta magna clinically presents as–
A) Recurrent otitis media
B) Dysphagia due to tonsillar hypertrophy
C) Nasal polyps
D) Conductive hearing loss
Answer: B) Dysphagia due to tonsillar hypertrophy
Explanation: Enlarged tonsillar crypts can cause obstructive symptoms including dysphagia. The other options relate to first pouch or nasal causes. Thus, B is correct.
10) The palatine tonsil lymphoid tissue infiltrates the epithelium derived from the–
A) First pouch
B) Second pouch
C) Third pouch
D) Fourth pouch
Answer: B) Second pouch
Explanation: Tonsillar lymphoid tissue invades the second pouch endodermal epithelium forming crypts. Thus, B is correct.
11) In tonsillectomy, bleeding is most likely from vessels associated with a structure derived from which pouch?
A) First
B) Second
C) Third
D) Fourth
Answer: B) Second
Explanation: Palatine tonsils (second pouch derivatives) receive blood supply from tonsillar branches of facial artery, which commonly bleed during tonsillectomy. Thus, B is correct.
Chapter: Embryology & Orthopedics; Topic: Bone Development; Subtopic: Types of Epiphyses
Keyword Definitions:
Pressure Epiphysis: Epiphysis involved in transmission of weight or pressure, e.g., head of femur.
Traction Epiphysis: Site where strong muscle pull occurs; develops due to traction forces (e.g. mastoid process).
Atavistic Epiphysis: Epiphysis representing a phylogenetic remnant, e.g., coracoid process.
Accessory Epiphysis: Additional epiphysis appearing occasionally, e.g., os trigonum.
Secondary Ossification Center: Center forming epiphysis after primary diaphyseal ossification.
1) Lead Question – 2016
Which of the following is a traction epiphysis?
A) Distal Radius
B) Mastoid process
C) Tibial Condyles
D) Coracoid Process
Answer: B) Mastoid process
Explanation: Traction epiphyses develop due to the pulling force exerted by attached muscles. The mastoid process is a classical example because the sternocleidomastoid muscle exerts strong traction, stimulating its secondary ossification. Distal radius and tibial condyles are pressure epiphyses involved in weight transmission, while the coracoid process is an atavistic epiphysis. Therefore, B is correct. Understanding epiphyseal types helps interpret growth patterns, skeletal development, and orthopedic conditions affecting growth centers.
2) Which of the following is an example of pressure epiphysis?
A) Greater trochanter
B) Head of femur
C) Mastoid process
D) Coracoid process
Answer: B) Head of femur
Explanation: Pressure epiphyses are involved in weight transmission across joints. The head of the femur is a classic pressure epiphysis because it participates in hip joint loading. The greater trochanter is a traction epiphysis, mastoid process also traction, and coracoid process is atavistic. Thus, B is correct, demonstrating the functional classification of epiphyses.
3) A patient suffers avulsion injury at the greater trochanter. This region is classified as–
A) Pressure epiphysis
B) Traction epiphysis
C) Atavistic epiphysis
D) Accessory epiphysis
Answer: B) Traction epiphysis
Explanation: The greater trochanter develops due to traction exerted by gluteal muscles. Avulsion fractures commonly occur at traction epiphyses where strong tendon pull is present. It is not a pressure or accessory epiphysis. Thus, B is correct.
4) The coracoid process is an example of–
A) Pressure epiphysis
B) Atavistic epiphysis
C) Traction epiphysis
D) Pathological epiphysis
Answer: B) Atavistic epiphysis
Explanation: The coracoid process represents a phylogenetic remnant, considered an atavistic epiphysis. It does not function primarily under pressure or traction. Thus, B is correct.
5) Which of the following is a traction epiphysis in the humerus?
A) Capitulum
B) Greater tubercle
C) Trochlea
D) Medial epicondyle
Answer: B) Greater tubercle
Explanation: The greater tubercle serves as the attachment for rotator cuff muscles, making it a traction epiphysis. Capitulum and trochlea are pressure epiphyses; medial epicondyle is an apophysis but traction is less significant. Thus, B is correct.
6) A radiograph of a child’s skull shows delayed development of mastoid process. This affects attachment of–
A) Trapezius
B) Sternocleidomastoid
C) Masseter
D) Temporalis
Answer: B) Sternocleidomastoid
Explanation: The SCM inserts into the mastoid process, which forms as a traction epiphysis. Delay in mastoid development may impair muscle attachment. Thus, B is correct.
7) Which of the following is an example of an accessory epiphysis?
A) Os trigonum
B) Tibial condyle
C) Mastoid process
D) Greater trochanter
Answer: A) Os trigonum
Explanation: The os trigonum is an accessory epiphysis occurring posterior to the talus. Tibial condyles are pressure epiphyses; mastoid and trochanter are traction epiphyses. Thus, A is correct.
8) Traction epiphysis forms due to–
A) Weight-bearing pressure
B) Muscle pull
C) Hormonal influence
D) Nutrient artery pattern
Answer: B) Muscle pull
Explanation: Continuous pull from attached muscles stimulates ossification centers forming traction epiphyses. Pressure epiphyses form from weight-bearing. Thus, B is correct.
9) The tibial tuberosity is classified as–
A) Pressure epiphysis
B) Traction epiphysis
C) Atavistic epiphysis
D) Pathological epiphysis
Answer: B) Traction epiphysis
Explanation: The tibial tuberosity is the insertion site of the patellar ligament subject to strong muscle pull from the quadriceps, making it a traction epiphysis. Thus, B is correct.
10) A boy with Osgood–Schlatter disease has inflammation in a traction epiphysis located at the–
A) Distal femur
B) Tibial tuberosity
C) Calcaneal tuberosity
D) Radial head
Answer: B) Tibial tuberosity
Explanation: Osgood–Schlatter disease affects the tibial tuberosity, a traction epiphysis due to quadriceps pull. Distal femur is a pressure epiphysis; calcaneal tuberosity is apophyseal; radial head is pressure-related. Thus, B is correct.
11) Which structure represents a traction epiphysis of the scapula?
A) Glenoid cavity
B) Coracoid process
C) Inferior angle
D) Acromion
Answer: D) Acromion
Explanation: The acromion develops due to traction exerted by deltoid and trapezius muscles, making it a traction epiphysis. Coracoid is atavistic. Glenoid cavity is a pressure epiphysis. Thus, D is correct.
Chapter: Histology; Topic: Liver; Subtopic: Liver Architecture & Cellular Components
Keyword Definitions:
Glisson’s Capsule: Fibrous connective tissue capsule surrounding the liver.
Space of Disse: Perisinusoidal space between hepatocytes and sinusoidal endothelium.
Stellate (Ito) Cells: Vitamin A–storing cells located in the space of Disse; responsible for fibrosis in liver injury.
Kupffer Cells: Macrophages lining hepatic sinusoids responsible for phagocytosis and immune defense.
Liver Lobule: Classic lobule is hexagonal, not pentagonal, centered around a central vein.
1) Lead Question – 2016
All of the following are true about the liver except?
A) It is covered by Glisson's capsule
B) Stellate cells are present in the space of Disse
C) Kupfer cells are the defense cells
D) The lobules in the liver are pentagonal
Answer: D) The lobules in the liver are pentagonal
Explanation: The liver is surrounded by Glisson’s capsule, a fibrous connective tissue sheath. Stellate (Ito) cells reside in the space of Disse and function in vitamin A storage and fibrosis. Kupffer cells are the resident macrophages providing immune defense. However, liver lobules are classically hexagonal, not pentagonal, with portal triads at the corners and a central vein at the center. Therefore, option D is incorrect. Knowledge of hepatic microanatomy helps understand liver pathology, regeneration, and responses to injury.
2) Kupffer cells are located in–
A) Space of Disse
B) Central vein
C) Lining of sinusoids
D) Portal triad
Answer: C) Lining of sinusoids
Explanation: Kupffer cells are macrophages that line the hepatic sinusoids. They clear bacteria, debris, and damaged erythrocytes. Space of Disse contains stellate cells, not Kupffer cells. Central vein drains blood; portal triad contains portal vein, hepatic artery, and bile ductule. Thus, C is correct.
3) A patient with chronic liver injury develops fibrosis due to activation of which cells?
A) Kupffer cells
B) Stellate cells
C) Hepatocytes
D) Endothelial cells
Answer: B) Stellate cells
Explanation: Stellate (Ito) cells in the space of Disse become myofibroblast-like during injury, producing collagen and causing fibrosis. Kupffer cells initiate inflammation but do not produce fibrosis. Thus, B is correct, identifying the main fibrogenic cell.
4) The portal triad includes all except–
A) Hepatic artery
B) Portal vein
C) Bile ductule
D) Central vein
Answer: D) Central vein
Explanation: Central vein lies at the center of the lobule, not within the portal triad. The triad contains hepatic artery, portal vein, and bile duct. Thus, D is correct.
5) Space of Disse is located between–
A) Hepatocytes and sinusoids
B) Bile ducts and hepatocytes
C) Kupffer cells and portal canal
D) Endothelium and bile canaliculi
Answer: A) Hepatocytes and sinusoids
Explanation: The space of Disse lies between hepatocytes and sinusoidal endothelial cells. It contains microvilli of hepatocytes and stellate cells. Thus, A is correct.
6) The functional unit based on bile flow direction is–
A) Classic hepatic lobule
B) Portal lobule
C) Hepatic acinus
D) Hexagonal triad
Answer: B) Portal lobule
Explanation: The portal lobule emphasizes bile drainage toward the portal triad. Classic lobule emphasizes blood flow to central vein; acinus emphasizes metabolic zones. Thus, B is correct.
7) A biopsy shows zone 3 hepatocyte necrosis. Zone 3 is closest to–
A) Portal triad
B) Central vein
C) Bile canaliculus
D) Glisson’s capsule
Answer: B) Central vein
Explanation: Zone 3 hepatocytes lie nearest the central vein and are most susceptible to hypoxia and toxins. Thus, B is correct.
8) Hepatocytes join to form bile canaliculi using–
A) Tight junctions
B) Hemidesmosomes
C) Desmosomes
D) Gap junctions
Answer: A) Tight junctions
Explanation: Tight junctions seal bile canaliculi between hepatocytes, preventing bile leakage. Desmosomes provide strength; gap junctions allow communication. Thus, A is correct.
9) Vitamin A is stored in the liver by–
A) Hepatocytes
B) Stellate cells
C) Kupffer cells
D) Bile duct cells
Answer: B) Stellate cells
Explanation: Stellate cells in the space of Disse store vitamin A in lipid droplets. Thus, B is correct.
10) In alcoholic liver disease, Mallory bodies are seen in–
A) Stellate cells
B) Endothelial cells
C) Hepatocytes
D) Kupffer cells
Answer: C) Hepatocytes
Explanation: Mallory–Denk bodies are cytoplasmic inclusions seen in hepatocytes, commonly in alcoholic hepatitis. Thus, C is correct.
11) Hepatic sinusoids differ from capillaries because they have–
A) Continuous endothelium
B) Fenestrated endothelium
C) Thick basement membrane
D) Double arterial supply
Answer: B) Fenestrated endothelium
Explanation: Hepatic sinusoids have discontinuous fenestrated endothelium and sparse basement membrane, allowing efficient exchange between blood and hepatocytes. Thus, B is correct.
Chapter: Histology; Topic: Liver Microanatomy; Subtopic: Biliary Pathways (Canals of Hering)
Keyword Definitions:
Canal of Hering: Short ductules connecting bile canaliculi to interlobular bile ducts; contain hepatic progenitor (oval) cells.
Bile Canaliculi: Tiny channels between hepatocytes formed by tight junctions; transport bile to the canals of Hering.
Portal Triad: Contains branch of hepatic artery, portal vein, and bile ductule.
Cholangiocytes: Epithelial cells lining bile ducts and Hering’s canals.
Liver Lobule: Hexagonal unit of hepatic parenchyma with central vein at center and portal triads at corners.
1) Lead Question – 2016
Hering's canal is present in?
A) Spleen
B) Liver
C) Kidney
D) Lung
Answer: B) Liver
Explanation: Hering’s canals, or bile ductules, are located in the liver and serve as transitional channels between hepatocytic bile canaliculi and the interlobular bile ducts within the portal triads. These canals contain cholangiocytes and hepatic progenitor cells (oval cells). They regulate bile flow and participate in liver regeneration. They are not present in spleen, kidney, or lung, which lack a biliary system. Therefore, option B is correct. Their clinical significance includes roles in primary biliary cholangitis and ductular reactions during liver injury.
2) Hering’s canals connect bile canaliculi to–
A) Central vein
B) Interlobular bile ducts
C) Hepatic artery
D) Lymphatic channels
Answer: B) Interlobular bile ducts
Explanation: Hering’s canals serve as transitional passageways conducting bile from canaliculi into interlobular bile ducts located within portal triads. They do not connect to lymphatics or blood vessels. Thus, B is correct.
3) A biopsy shows proliferation of oval cells. These progenitor cells are located in–
A) Canal of Hering
B) Space of Disse
C) Central vein
D) Kupffer cells
Answer: A) Canal of Hering
Explanation: Oval cells, hepatic progenitors, reside in the canals of Hering. They proliferate during severe liver injury when hepatocyte regeneration is impaired. Thus, A is correct.
4) Which of the following is lined by cholangiocytes?
A) Bile canaliculi
B) Hering’s canal
C) Sinusoids
D) Central vein
Answer: B) Hering’s canal
Explanation: Cholangiocytes line bile ducts and Hering’s canals. Bile canaliculi are formed by hepatocytes, not cholangiocytes. Thus, B is correct.
5) The earliest site of bile duct injury in primary biliary cholangitis is–
A) Hering’s canal
B) Bile canaliculi
C) Central vein
D) Sinusoids
Answer: A) Hering’s canal
Explanation: Primary biliary cholangitis commonly targets small bile ductules including Hering’s canals. Canaliculi and sinusoids are unaffected early. Thus, A is correct.
6) Hering’s canals are found at the junction of–
A) Central vein and sinusoids
B) Hepatocytes and portal tract
C) Hepatic artery and bile duct
D) Sinusoids and lymphatics
Answer: B) Hepatocytes and portal tract
Explanation: They lie between hepatocyte canaliculi and the portal triad region. Thus, B is correct.
7) Which structure carries bile opposite to the direction of blood flow?
A) Sinusoids
B) Bile canaliculi
C) Central vein
D) Hepatic artery
Answer: B) Bile canaliculi
Explanation: Bile canaliculi drain bile toward portal triads while blood moves toward the central vein. Thus, B is correct.
8) Oval cell activation is increased in–
A) Severe alcoholic hepatitis
B) Acute pancreatitis
C) Nephrotic syndrome
D) Pulmonary embolism
Answer: A) Severe alcoholic hepatitis
Explanation: When hepatocyte regeneration is limited, progenitor oval cells in Hering’s canals proliferate, such as in severe alcoholic hepatitis. Thus, A is correct.
9) The space between hepatocyte microvilli and sinusoidal endothelium is–
A) Space of Disse
B) Canal of Hering
C) Space of Mall
D) Bile canaliculus
Answer: A) Space of Disse
Explanation: Space of Disse lies between hepatocytes and sinusoidal endothelium. Thus, A is correct.
10) Smallest functional unit emphasizing metabolic zones is–
A) Portal lobule
B) Hepatic acinus
C) Classic lobule
D) Biliary lobule
Answer: B) Hepatic acinus
Explanation: Acinus classification describes zones 1–3 with differing oxygenation and metabolic activity. Thus, B is correct.
11) In cholestasis, bile accumulation begins in–
A) Canaliculi
B) Sinusoids
C) Central vein
D) Space of Disse
Answer: A) Canaliculi
Explanation: Bile builds up first in canaliculi before affecting ducts or hepatocytes. Thus, A is correct.
Chapter: Histology; Topic: Pituitary Gland; Subtopic: Neurohypophysis (Posterior Pituitary)
Keyword Definitions:
Herring Bodies: Dilated axonal swellings in neurohypophysis storing oxytocin and vasopressin.
Neurohypophysis: Posterior pituitary composed of unmyelinated axons, pituicytes, and Herring bodies.
Pars Nervosa: Main component of the neurohypophysis storing neurosecretory granules.
Pituicytes: Supporting glial cells of posterior pituitary.
Hypothalamo-hypophyseal Tract: Axonal pathway carrying hormones from hypothalamus to neurohypophysis.
1) Lead Question – 2016
Herring's bodies are present in?
A) Pars tuberalis
B) Pars intermedia
C) Neurohypophysis
D) Pars terminalis
Answer: C) Neurohypophysis
Explanation: Herring bodies are dilated terminal portions of hypothalamic axons located in the neurohypophysis (posterior pituitary). They store and release oxytocin and vasopressin produced in the hypothalamic nuclei. Pars tuberalis and pars intermedia belong to the anterior pituitary and do not contain Herring bodies. Pars terminalis is not a histological subdivision of the pituitary gland. Therefore, C is the correct answer. Recognition of these structures is essential in pituitary histology, especially in disorders affecting ADH secretion.
2) Oxytocin is released from which part of pituitary?
A) Pars distalis
B) Pars intermedia
C) Neurohypophysis
D) Pars tuberalis
Answer: C) Neurohypophysis
Explanation: Oxytocin is synthesized in hypothalamic nuclei and transported to the neurohypophysis, where it is stored in Herring bodies and released into blood. Thus, C is correct.
3) Herring bodies represent accumulation of–
A) Growth hormone
B) Neurosecretory granules
C) Dopamine
D) Releasing hormones
Answer: B) Neurosecretory granules
Explanation: Herring bodies are axonal swellings containing granules of vasopressin and oxytocin. Thus, B is correct.
4) The posterior pituitary contains which supporting cells?
A) Chromophils
B) Chromophobes
C) Pituicytes
D) Folliculostellate cells
Answer: C) Pituicytes
Explanation: Pituicytes are modified glial cells supporting axons in neurohypophysis. Thus, C is correct.
5) A patient with central diabetes insipidus lacks which hormone at the target level?
A) ADH
B) ACTH
C) GH
D) Prolactin
Answer: A) ADH
Explanation: ADH is stored and released from neurohypophysis; deficiency leads to central DI. Thus, A is correct.
6) Which nucleus produces ADH?
A) Arcuate nucleus
B) Paraventricular nucleus
C) Supraoptic nucleus
D) Ventromedial nucleus
Answer: C) Supraoptic nucleus
Explanation: Supraoptic nucleus primarily produces ADH. Paraventricular mainly produces oxytocin. Thus, C is correct.
7) In which region do Herring bodies accumulate along axons?
A) Pars intermedia
B) Neurohypophysis
C) Pars tuberalis
D) Median eminence
Answer: B) Neurohypophysis
Explanation: Herring bodies are exclusive to the posterior pituitary. Thus, B is correct.
8) Neurohypophysis develops from which embryonic tissue?
A) Oral ectoderm
B) Neural ectoderm
C) Mesoderm
D) Endoderm
Answer: B) Neural ectoderm
Explanation: Posterior pituitary originates from neuroectoderm of diencephalon. Thus, B is correct.
9) Hormones in Herring bodies reach bloodstream via–
A) Venous sinusoids
B) Fenestrated capillaries
C) Lymphatic ducts
D) Tight junction channels
Answer: B) Fenestrated capillaries
Explanation: Neurohypophysis uses fenestrated capillaries for rapid hormone release. Thus, B is correct.
10) Pars intermedia contains which characteristic structure?
A) Rathke’s cysts
B) Herring bodies
C) Pituicytes
D) Chromophils
Answer: A) Rathke’s cysts
Explanation: Pars intermedia often contains colloid-filled Rathke’s cleft cysts. Thus, A is correct.
11) Damage to neurohypophysis leads to which clinical manifestation?
A) Hyperprolactinemia
B) SIADH
C) Polyuria and polydipsia
D) Cushing syndrome
Answer: C) Polyuria and polydipsia
Explanation: Injury impairs ADH release leading to central diabetes insipidus, presenting with polyuria and polydipsia. Thus, C is correct.