Embryology and Development Practice Questions

Q: Space of Cloquet is phylogenetically related to

Hyaloid artery. ***Hyaloid artery*** - The **Space of Cloquet** (also known as the hyaloid canal or retrolental space of Cloquet) is the embryonic remnant of the **hyaloid artery**. - During fetal development, the hyaloid artery nourishes the developing lens and vitreous, and usually regresses completely before birth, leaving behind the empty canal. *Iris* - The iris is the colored part of the eye responsible for controlling pupil size and light entry, and its development is distinct from the hyaloid artery system. - While it plays a crucial role in the mature eye, it does not share a direct phylogenetic or developmental connection with Cloquet's space. *Central Retinal artery* - The central retinal artery supplies blood to the inner layers of the retina and is a branch of the ophthalmic artery. - It develops separately and has a different function than the hyaloid artery system, which is primarily involved in early ocular development. *Central retinal vein* - The central retinal vein drains blood from the retina and is also a distinct vascular structure separate from the hyaloid artery. - Its development and function are related to retinal blood outflow, not the regression of fetal vitreous structures.

Q: Branchial cyst arises from which branchial cleft:

Second. ***Second*** - **Branchial cysts** most commonly arise from the **incomplete obliteration of the second branchial cleft** (90-95% of all branchial cysts). - They typically present as a **smooth, mobile, non-tender mass** in the lateral neck, anterior to the sternocleidomastoid muscle [1]. - Most common presentation: a painless swelling in the **upper third of the neck** along the anterior border of SCM [1]. *Third* - Cysts arising from the **third branchial cleft** are very rare and typically present lower in the neck, often extending towards the **pyriform sinus**. - These are less common than second branchial cleft cysts and may be associated with **thyroid or parathyroid abnormalities**. *First* - Anomalies of the **first branchial cleft** are rare and typically manifest as cysts or sinuses close to the **external auditory canal** or angle of the mandible. - They are often associated with the **parotid gland** and facial nerve. *Fourth* - **Fourth branchial cleft anomalies** are also very rare and usually present as a sinus or fistula in the lower neck, often entering the **pyriform sinus** and associated with recurrent infections. - They have a distinct tract that can connect to the pharynx.

Q: The following ocular structure is not derived from surface ectoderm –

Sclera. **Sclera** - The **sclera** develops from the **neural crest cells**, which differentiate into mesenchymal tissue around the optic cup, forming the fibrous coats of the eye [1]. - It is part of the **fibrous tunic** of the eye, along with the cornea, and provides structural support. *Epithelium of lacrimal glands* - The **epithelium of lacrimal glands** originates from the **surface ectoderm** through invaginations and subsequent differentiation. - These glands are responsible for producing the **watery component of tears**. *Crystalline lens* - The **crystalline lens** also develops from the **surface ectoderm**, specifically from the lens placode, which invaginates to form the lens vesicle. - It is crucial for **focusing light** onto the retina. *Corneal epithelium* - The **corneal epithelium** is derived from the **surface ectoderm** and forms the outermost layer of the cornea [1]. - It provides a **protective barrier** and helps maintain the smooth refractive surface of the cornea [1].

Q: Acrosome cap of the sperm derived from ?

Golgi body. Golgi body - During spermiogenesis, the Golgi apparatus in the spermatid migrates to the anterior pole of the cell and condenses to form the acrosomal vesicle [1]. - This vesicle then spreads over the anterior half of the nucleus to become the acrosome cap, which contains hydrolytic enzymes crucial for fertilization [1]. Nucleus - The nucleus contains the genetic material (DNA) of the sperm, but it does not directly form the acrosome cap [1]. - The nucleus is located posterior to the acrosome, and its primary function is to transmit paternal chromosomes. Mitochondria - Mitochondria are concentrated in the midpiece of the sperm, providing ATP for flagellar movement [1]. - They are essential for sperm motility but play no role in the formation of the acrosome cap. Centriole - The proximal and distal centrioles are located at the base of the nucleus and are involved in forming the axoneme (the core of the flagellum). - Centrioles are critical for sperm tail development and function, but not for acrosome formation.

Q: All of the following develops from surface ectoderm except

Epithelial lining of iris. Epithelial lining of iris (Correct Answer) - The epithelial lining of the iris develops from the neuroectoderm (specifically, the anterior extension of the optic cup), not the surface ectoderm. - This neuroectodermal origin differentiates it from other ocular structures that do arise from surface ectoderm. - Both layers of the iris epithelium (anterior and posterior pigmented layers) are derived from the two layers of the optic cup. [1] Lens (Incorrect) - The lens is a classic derivative of the surface ectoderm, forming as the lens placode invaginates after induction by the optic vesicle. - Its development is crucial for vision and is a key example of surface ectoderm differentiation in the head region. Lacrimal gland (Incorrect) - The lacrimal gland, responsible for tear production, develops from the surface ectoderm of the conjunctival sac. - It forms through a series of epithelial buds that invaginate into the surrounding mesenchyme. Epithelial lining of conjunctiva (Incorrect) - The epithelial lining of the conjunctiva, which covers the sclera and lines the eyelids, is derived from the surface ectoderm. [2] - This layer provides protection and lubrication to the eye.

Q: Nasolabial cyst occurs at-

Union of nasal and maxillary process. ***Union of nasal and maxillary process*** - A nasolabial cyst (also known as a nasoalveolar cyst or Klestadt's cyst) is a **non-odontogenic cyst** believed to arise from remnants of the **nasolacrimal duct** at the junction of embryonic facial processes. - This specific location corresponds to the fusion of the **lateral nasal process** and the **maxillary process**, leading to a cyst in the soft tissue of the upper lip lateral to the ala of the nose. *Union of palatal process with maxillary* - Cysts arising from the fusion of the palatal process with the maxillary process typically result in **globulomaxillary cysts**, which are located between the maxillary lateral incisor and canine. - This embryological origin differs significantly from the location of a nasolabial cyst. *Nasal with palatal process* - This union is not a recognized embryonic facial fusion point that correlates with the formation of a specific cyst type like the nasolabial cyst. - Cysts related to the palate generally involve palatal processes or median palatal structures. *Union of two nasal processes* - The fusion of the medial nasal processes forms the **primary palate** and the premaxilla; cysts in this central region are often **median palatal cysts** or **nasopalatine duct cysts**. - This location is distinct from the lateral soft tissue location of a nasolabial cyst.

Q: Gland homologous to prostate in females is

Skene's gland. ***Skene's gland*** - **Skene's glands**, also known as the **paraurethral glands**, are located on either side of the female urethra [1]. - They are considered homologous to the male prostate gland as they share similar embryological origins and secrete a fluid that is believed to play a role in sexual function [1]. *Bartholin's gland* - **Bartholin's glands** are located at the posterior aspect of the vaginal opening and secrete mucus to lubricate the vagina. - These glands are homologous to the **bulbourethral glands (Cowper's glands)** in males, not the prostate [1]. *Gartner's duct* - **Gartner's duct** is a vestigial remnant of the **Wolffian (mesonephric) duct** in females. - It is not a functional gland and has no homology to the prostate gland. - Gartner's duct cysts may occasionally be found along the anterolateral wall of the vagina. *Cowper's gland* - **Cowper's glands**, or **bulbourethral glands**, are male accessory glands located below the prostate. - Their female homologue is the **Bartholin's gland**, not the prostate [1].

Q: Cantrell pentalogy include all except

Trisomy 21. ***Trisomy 21*** - **Cantrell's pentalogy** is a rare congenital condition involving defects of the **diaphragm**, **abdominal wall**, **pericardium**, **sternum**, and **heart**. - **Trisomy 21 (Down syndrome)** is a chromosomal abnormality characterized by distinct facial features, intellectual disability, and various congenital anomalies, but it is not a component of Cantrell's pentalogy. *ASD* - An **atrial septal defect (ASD)** is a common cardiac anomaly found in Cantrell's pentalogy, resulting from improper development of the heart. - The cardiac defect is one of the five primary components of **Cantrell's pentalogy**. *VSD* - A **ventricular septal defect (VSD)** is another frequent cardiac defect associated with Cantrell's pentalogy. - This defect involves a hole in the wall separating the two lower chambers of the heart and is a key feature of the **cardiac malformation component**. *TOF* - **Tetralogy of Fallot (TOF)** is a complex congenital heart defect often seen in cases of Cantrell's pentalogy. - It comprises four specific heart anomalies and contributes to the significant **cardiovascular malformations** in this syndrome.

Q: The hydatid of Morgagni is a cystic remnant of

Fallopian tube. ***Fallopian tube*** - The **hydatid of Morgagni** (also called **appendix vesiculosa**) is a small cystic structure found on the **fimbriated end of the fallopian tube** in females [1]. - It represents an embryonic remnant of the **paramesonephric (Müllerian) duct** [1]. - These cysts are typically **asymptomatic** unless they undergo **torsion**, which can cause acute pelvic pain. - The term "hydatid of Morgagni" can also refer to the **appendix testis** in males, which is also a Müllerian duct remnant. *Cervix* - The cervix is the lower part of the uterus and develops from the **paramesonephric duct**, but the hydatid of Morgagni specifically refers to the fimbrial cyst, not cervical structures. - **Nabothian cysts** can occur in the cervix but are **retention cysts** from blocked cervical glands, not embryonic remnants. *Ovary* - Ovaries develop from the **gonadal ridge** and can have various cysts (**follicular, corpus luteum**), but these are functional or neoplastic, not embryonic duct remnants [2]. - The hydatid of Morgagni is specifically an **adnexal structure** associated with the fallopian tube, not the ovary itself. *Uterus* - The uterine body develops from fusion of the **paramesonephric ducts**, but the hydatid of Morgagni is specifically located at the **fimbriated end of the fallopian tube** [3]. - Uterine pathologies include **leiomyomas** and **endometrial polyps**, which are unrelated to the hydatid of Morgagni.

Question 1

Space of Cloquet is phylogenetically related to

Accepted Answer

Hyaloid artery

Answer

Iris

Answer

Central Retinal artery

Answer

Central retinal vein

Question 2

Branchial cyst arises from which branchial cleft:

Accepted Answer

Second

Answer

Third

Answer

First

Answer

Fourth

Question 3

The following ocular structure is not derived from surface ectoderm –

Accepted Answer

Sclera

Answer

Epithelium of lacrimal glands

Answer

Crystalline lens

Answer

Corneal epithelium

Question 4

Acrosome cap of the sperm derived from ?

Accepted Answer

Golgi body

Answer

Nucleus

Answer

Mitochondria

Answer

Centriole

Question 5

All of the following develops from surface ectoderm except

Accepted Answer

Epithelial lining of iris

Answer

Lens

Answer

Lacrimal gland

Answer

Epithelial lining of conjunctiva

Question 6

Nasolabial cyst occurs at-

Accepted Answer

Union of nasal and maxillary process

Answer

Union of palatal process with maxillary

Answer

Union of nasal with palatal process

Answer

Union of two nasal processes

Question 7

Gland homologous to prostate in females is

Accepted Answer

Skene's gland

Answer

Bartholin's gland

Answer

Gartner's duct

Answer

Cowper's gland

Question 8

Cantrell pentalogy include all except

Accepted Answer

Trisomy 21

Answer

ASD

Answer

VSD

Answer

TOF

Question 9

The hydatid of Morgagni is a cystic remnant of

Accepted Answer

Fallopian tube

Answer

Cervix

Answer

Ovary

Answer

Uterus

Question 10

In development of male fetus following statements are true except

Accepted Answer

During intrauterine life, testes do not produce hormones essential for male development.

Answer

Around 8 weeks internal and external genitalia differentiates into male pattern

Answer

Gene on short arm of Y chromosome directs testes development

Answer

Antimullerian hormone inhibits development of mullerian system in male fetus

Embryology and Development — MCQs

Embryology and Development — MCQs

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