NEET-PG 2015 - Anatomy Practice Questions

Q: Which structure may persist as a remnant of the Müllerian duct in males?

Prostatic utricle. ***Prostatic utricle*** - The **Müllerian ducts** (paramesonephric ducts) are primarily female reproductive structures. In males, the **anti-Müllerian hormone (AMH)** causes their regression. - The **prostatic utricle** is a small blind-ended pouch located at the prostatic urethra, representing the remnant of the fused caudal ends of the Müllerian ducts. *Seminal vesicle* - The **seminal vesicles** develop from the **mesonephric (Wolffian) ducts**, not the Müllerian ducts. - They contribute to semen production and are functional male reproductive organs, not remnants of female structures. *Epididymis* - The **epididymis** also develops from the **mesonephric (Wolffian) ducts**. - It functions in sperm maturation and storage and is part of the male reproductive tract, not a Müllerian remnant. *Ureter* - The **ureters** are conduits for urine from the kidneys to the bladder and develop from the **ureteric bud**, an outgrowth of the mesonephric duct, but are distinct from Müllerian structures. - They are part of the urinary system in both sexes and are not considered remnants of the Müllerian duct.

Q: Which type of glial cell is derived from mesodermal origin?

Microglial cells. ***Microglial cells*** - **Microglial cells** are unique among glial cells as they originate from **mesoderm**, specifically from **monocyte/macrophage precursors** in the bone marrow [1]. - They function as the **immune cells of the central nervous system (CNS)**, scavenging for plaques, damaged neurons, and infectious agents [1]. *Macroglial cells* - This is a broad category that includes **astrocytes, oligodendrocytes, and ependymal cells**, all of which are derived from **neuroectoderm**, not mesoderm [1]. - They perform various supportive roles but are distinct in origin from microglial cells [1]. *Oligodendrocytes* - **Oligodendrocytes** are derived from **neuroectoderm** and are responsible for forming the **myelin sheath** around axons in the CNS [2]. - Myelination is crucial for rapid and efficient nerve impulse conduction. *Ependymal cells* - **Ependymal cells** are derived from **neuroectoderm** and line the **ventricles of the brain** and the **central canal of the spinal cord**. - They play a role in the production and circulation of **cerebrospinal fluid (CSF)**.

Q: Trigone of bladder is derived from?

Mesonephric duct. The trigone of the bladder is formed from the caudal ends of the **mesonephric ducts**, which are absorbed into the primitive bladder wall [1]. This mesenchymal origin explains why the trigone has a smooth lining [1] and is less prone to infection compared to the rest of the bladder. *Paramesonephric duct* - The **paramesonephric ducts** (Müllerian ducts) are involved in forming the female reproductive organs, specifically the fallopian tubes, uterus [2], and upper vagina. - They do not contribute to the formation of the urinary bladder or its trigone. *Absorbed anal membrane* - The **anal membrane** separates the endoderm-derived hindgut from the ectoderm-derived anal pit. - Its absorption is relevant to the development of the anus, not the urinary bladder. *Mullerian duct* - The **Müllerian ducts** are synonymous with the paramesonephric ducts and are primarily involved in the development of the female reproductive tract [2]. - They play no role in the development of the urinary bladder or its trigone.

Q: Sertoli cells are derived from -

Coelomic epithelium. Sertoli cells are derived from the **coelomic epithelium** (surface epithelium) of the urogenital ridge during gonadal development. - The coelomic epithelium proliferates to form the **primitive sex cords** (medullary cords in males), and cells within these cords differentiate into Sertoli cells. - These cells are essential for **spermatogenesis**, providing structural support and nutrition to developing germ cells, and producing **anti-Müllerian hormone (AMH)** which causes regression of Müllerian ducts in male development [1]. *Germinal epithelium* - This is an **outdated term** previously used for the surface epithelium of the gonad, based on the misconception that it gave rise to germ cells. - Modern embryology uses the term **coelomic epithelium** or surface epithelium instead. - While historically used, this terminology is no longer preferred in current medical literature. *Genital swelling* - **Genital swellings** (labioscrotal swellings) are external mesodermal structures that develop into the **scrotum** in males or **labia majora** in females. - These are external genitalia components and are not the source of internal testicular cells like Sertoli cells. *Primordial germ cells* - **Primordial germ cells (PGCs)** originate from the epiblast, migrate via the hindgut to the developing gonads, and differentiate into **spermatogonia** (males) or **oogonia** (females) [1]. - They form the **germ cell lineage** (gametes), not somatic support cells like Sertoli cells, which are of coelomic epithelial origin.

Q: Spleniculi are most commonly found in which of the following locations?

Hilum of the spleen. No relevant citations could be added to the explanation as the provided text passages did not contain information regarding spleniculi (accessory spleens), their location, or their embryology. ***Hilum of the spleen*** - **Spleniculi** (accessory spleens) are most commonly found at the **hilum of the spleen**, accounting for approximately **75% of cases**. - During **embryonic development**, the spleen forms from mesenchymal tissue in the dorsal mesogastrium, and small fragments of splenic tissue can separate and persist as accessory spleens. - The **splenic hilum** is the most frequent location due to the close proximity during development, followed by the gastrosplenic ligament, tail of pancreas, and greater omentum. - Accessory spleens are found in **10-30% of the population** and are clinically significant in conditions requiring complete splenectomy (e.g., ITP, hereditary spherocytosis). *Colon* - The colon is part of the **gastrointestinal tract** with a completely different embryological origin (endodermal). - Splenic tissue development occurs in the **dorsal mesogastrium** (mesodermal origin), making the colon an anatomically and embryologically implausible location for spleniculi. *Liver* - The liver develops from the **ventral foregut endoderm** and is anatomically distant from the spleen's developmental region. - **Splenosis** (traumatic implantation) could theoretically occur, but congenital spleniculi in the liver are exceptionally rare and not a recognized common location. *Lungs* - The lungs are part of the **respiratory system**, developing from the foregut endoderm in the thoracic cavity. - There is no embryological connection between lung and splenic tissue development, making this an impossible location for congenital accessory spleens.

Q: What structure passes through the quadrangular space?

Axillary nerve. Axillary nerve - The axillary nerve and the posterior circumflex humeral artery are the primary structures that pass through the quadrangular space. - Compression or injury within this space can lead to deficits in the axillary nerve's distribution, affecting the deltoid and teres minor muscles. *Radial nerve* - The radial nerve passes through the triangular interval, not the quadrangular space. - It supplies the triceps muscle and all muscles in the posterior compartment of the forearm. *Median nerve* - The median nerve travels through the cubital fossa and then down the anterior forearm, supplying most of the forearm flexors and some hand muscles. - It does not pass through any of the posterior axillary spaces. *Brachial Artery* - The brachial artery is the main arterial supply to the arm and runs anteriorly in the arm, deep to the biceps brachii muscle. - It does not pass through the quadrangular space; rather, the posterior circumflex humeral artery (a branch of the axillary artery) traverses this space.

Q: Seminal colliculus is present in ?

Urethra. ***Correct: Urethra*** - The **seminal colliculus** (also known as the **verumontanum**) is a prominent ridge located on the posterior wall of the **prostatic urethra** - It contains the openings of the **ejaculatory ducts** and the **prostatic utricle** - This is a key anatomical landmark in the male urethra during endoscopic procedures *Incorrect: Prostate* - While the seminal colliculus is located within the portion of the urethra that passes through the prostate (prostatic urethra), it is not a structure *of* the prostate gland itself - The prostate is a gland that surrounds the urethra and contributes to seminal fluid - The seminal colliculus is an intraluminal urethral structure, not prostatic tissue *Incorrect: Testis* - The testis is the primary male reproductive organ responsible for **spermatogenesis** and hormone synthesis (testosterone) - It does not contain the seminal colliculus, which is located in the pelvic urethra *Incorrect: Scrotum* - The scrotum is an external dermal sac that houses the testes, epididymis, and lower spermatic cords - It provides temperature regulation for spermatogenesis - The seminal colliculus is an internal pelvic structure, not present in the scrotum

Q: Which of the following is not a derivative of foregut?

Cecum. ***Cecum*** - The **cecum** and the entire large intestine (except the distal third of the transverse colon) are derivatives of the **midgut** [1]. - The midgut is supplied by the **superior mesenteric artery**, differentiating it developmentally from the foregut. *First part of the duodenum* - The **first part of the duodenum** (from the pylorus to the major duodenal papilla) is derived from the **foregut**. - This section receives its blood supply from branches of the **celiac trunk**, consistent with its foregut origin. *Liver* - The **liver** develops as a budding from the distal foregut and is therefore a **foregut derivative** [2]. - It plays a crucial role in metabolism and detoxification, consistent with its early development from this segment. *Pancreas* - The **pancreas** develops from dorsal and ventral buds of the distal foregut, making it a **foregut derivative**. - Both its exocrine and endocrine functions are vital for digestion and glucose homeostasis.

Q: Which Brodmann's area is primarily associated with motor speech?

Area 44. Area 44 - **Brodmann Area 44** is primarily known as **Broca's area**, which is critical for **motor speech production** and language processing [1]. - Damage to this area typically results in **Broca's aphasia**, characterized by non-fluent speech and difficulty forming complete sentences [1]. Area 1, 2, 3 - These Brodmann areas constitute the **primary somatosensory cortex**, responsible for processing **tactile and proprioceptive information** from the body. - They are involved in sensory perception, not directly with motor speech production. Area 4, 6 - **Brodmann Area 4** is the **primary motor cortex**, involved in executing voluntary movements [2]. **Brodmann Area 6** is the **premotor and supplementary motor cortex**, involved in planning and coordinating movements [2]. - While these areas are crucial for motor control, they are not specifically associated as the primary center for motor speech in the same way Broca's area is. Area 40 - **Brodmann Area 40**, also known as the **supramarginal gyrus**, is part of the **parietal lobe** and is involved in phonological processing, language perception, and spatial cognition. - While it plays a role in language, it is not the primary area for motor speech production.

Q: In the context of blood pressure regulation, where are baroreceptors primarily located?

Tunica adventitia. ***Tunica adventitia*** - **Baroreceptors** are specialized mechanoreceptive nerve endings that detect changes in blood pressure by sensing arterial wall stretch. - These sensory nerve endings are primarily located in the **tunica adventitia** (outermost layer) of the **carotid sinus** and **aortic arch** [1]. - The adventitia contains the **nerve fibers and endings** (including baroreceptors), as well as the vasa vasorum and connective tissue supporting the vessel wall [1]. - The nerve terminals extend from the adventitia toward the adventitial-medial border where they sense wall tension changes. *Tunica media* - The **tunica media** is the middle layer composed of **smooth muscle cells** and elastic fibers. - While this layer responds to stretch and changes thickness with blood pressure variations, it does **not contain nerve endings or baroreceptors** [1]. - The media is responsible for vasoconstriction and vasodilation but lacks the sensory innervation needed for baroreception. *Tunica intima* - The **tunica intima** is the innermost layer lined by **endothelial cells**. - Its primary functions include providing a smooth surface for blood flow and regulating vascular permeability. - This layer does not house baroreceptors or other mechanoreceptive nerve endings. *None of the options* - This option is incorrect because **tunica adventitia** is indeed the correct location of baroreceptors. - The adventitia contains the neural elements necessary for blood pressure sensing in these specialized arterial regions [1].

Question 1

Which structure may persist as a remnant of the Müllerian duct in males?

Accepted Answer

Prostatic utricle

Answer

Seminal vesicle

Answer

Epididymis

Answer

Ureter

Question 2

Which type of glial cell is derived from mesodermal origin?

Accepted Answer

Microglial cells

Answer

Macroglial cells

Answer

Oligodendrocytes

Answer

Ependymal cells

Question 3

Trigone of bladder is derived from?

Accepted Answer

Mesonephric duct

Answer

Paramesonephric duct

Answer

Absorbed anal membrane

Answer

Mullerian duct

Question 4

Sertoli cells are derived from -

Accepted Answer

Coelomic epithelium

Answer

Genital swelling

Answer

Primordial germ cells

Answer

Germinal epithelium

Question 5

Spleniculi are most commonly found in which of the following locations?

Accepted Answer

Hilum of the spleen

Answer

Colon

Answer

Liver

Answer

Lungs

Question 6

What structure passes through the quadrangular space?

Accepted Answer

Axillary nerve

Answer

Radial nerve

Answer

Median nerve

Answer

Brachial Artery

Question 7

Seminal colliculus is present in ?

Accepted Answer

Urethra

Answer

Testis

Answer

Prostate

Answer

Scrotum

Question 8

Which of the following is not a derivative of foregut?

Accepted Answer

Cecum

Answer

Liver

Answer

Pancreas

Answer

First part of the duodenum

Question 9

Which Brodmann's area is primarily associated with motor speech?

Accepted Answer

Area 44

Answer

Area 1, 2, 3

Answer

Area 4, 6

Answer

Area 40

Question 10

In the context of blood pressure regulation, where are baroreceptors primarily located?

Accepted Answer

Tunica adventitia

Answer

Tunica intima

Answer

None of the options

Answer

Tunica media

NEET-PG 2015 — Anatomy