NEET-PG 2015 - Anatomy Practice Questions

Q: B cells are located in which region of lymph nodes?

Cortical follicles. ***Cortical follicles*** - **B cells** are predominantly found within the **cortical follicles** of lymph nodes, where they mature and become activated upon encountering antigens [2]. - These follicles can be primary (inactive) or secondary (active, containing **germinal centers** for B cell proliferation and differentiation). *Paracortical region* - The **paracortical region** is primarily occupied by **T cells** and is the site where T cells interact with antigen-presenting cells [1]. - While it's adjacent to B cell areas, it's not the primary location for B cells. *Medullary sinuses* - **Medullary sinuses** are channels in the medulla of the lymph node, containing macrophages and plasma cells, which are *differentiated B cells*. - They are not the primary residence for undifferentiated B cells. *Subcapsular region* - **Subcapsular region** is the space immediately beneath the capsule of the lymph node where lymph initially enters. - It contains macrophages and dendritic cells that sample antigens but is not a primary B cell zone.

Q: Intercalated disc is present in:

Cardiac muscle. ***Cardiac muscle*** - **Intercalated discs** are unique structures found only in cardiac muscle, forming specialized cell-cell junctions [1]. - These discs contain **gap junctions** for electrical coupling and **desmosomes** for strong adhesion, allowing the heart muscle to contract in a coordinated fashion. *Smooth muscle* - **Smooth muscle cells** are spindle-shaped and lack striations and organized sarcomeres. - They do not possess intercalated discs; instead, communication and coordination are often mediated by **gap junctions** scattered along the cell membranes [2]. *Skeletal muscle* - **Skeletal muscle cells** are long, multinucleated, and highly organized with prominent striations [3]. - They do not have intercalated discs as individual muscle fibers are innervated separately and generally do not directly communicate via specialized junctions for coordinated contraction. *All of the options* - As **intercalated discs** are characteristic features *only* of **cardiac muscle**, this option is incorrect. - Their presence in all three muscle types would contradict the specific cellular organization of smooth and skeletal muscle.

Q: Where do primitive red blood cells first originate during early embryonic development?

Yolk sac. ***Yolk sac*** - The **yolk sac** is the primary site of **hematopoiesis** during the first few weeks of embryonic development. - Primitive erythroid cells (red blood cells) originate here to supply the developing embryo with oxygen. *Liver* - The **liver** takes over as the main hematopoietic organ from about the 6th week of gestation, after the yolk sac [1]. - While it produces various blood cells, it is not the *first* site of primitive red blood cell formation. *Bone marrow* - **Bone marrow** becomes the primary site of hematopoiesis during the **fetal period** (around the 20th to 24th week) and continues throughout postnatal life [2]. - It is not involved in the initial production of primitive red blood cell formation in early embryogenesis. *Spleen* - The **spleen** plays a minor role in fetal hematopoiesis, mainly producing lymphoid cells and some myeloid cells, and can take on myeloid functions if the bone marrow is compromised. - It is not the initial site of red blood cell production in the early embryo.

Q: Which organ receives dual blood supply with both sources contributing to its primary metabolic function?

Liver. ***Liver*** - The liver receives blood from two sources: the **hepatic artery** (supplying oxygenated blood, ~25% of blood flow) and the **hepatic portal vein** (supplying nutrient-rich, deoxygenated blood from the gastrointestinal tract, ~75% of blood flow). - Both blood supplies are essential for the liver's primary metabolic functions, detoxification, and nutrient processing [1]. - This is the classic example of dual blood supply in medical education. *Heart* - The heart receives its blood supply primarily from the **coronary arteries**, which branch off the aorta. - While it has an extensive arterial network, it has a single primary source of blood supply. *Kidney* - The kidneys receive their blood supply exclusively from the **renal arteries**, which branch directly from the aorta. - Each kidney typically has a single renal artery supplying it for high-pressure filtration. *Lung* - The lungs do receive blood from two sources: **pulmonary arteries** (deoxygenated blood for gas exchange) and **bronchial arteries** (oxygenated blood for tissue nourishment, <5% of flow). - However, the primary function (gas exchange) is served by pulmonary circulation alone, while bronchial circulation only nourishes lung tissue. - The liver is the standard answer for dual blood supply where both sources serve the organ's primary function.

Q: Which of the following structures does NOT pass through Calot's triangle?

Portal vein. ***Portal vein*** - The **portal vein** is located within the **porta hepatis** and does not pass through Calot's triangle, making it the correct answer to this question. - It carries venous blood from the **gastrointestinal tract** and **spleen** to the liver and is positioned medial and posterior to the structures within Calot's triangle. *Right hepatic artery* - The **right hepatic artery** is a key structure that passes through Calot's triangle and forms one of its boundaries. - It typically gives rise to the **cystic artery** within or near the triangle, making it an important anatomical landmark during **cholecystectomy**. *Lymph node of Lund* - The **lymph node of Lund** (cystic lymph node) is consistently found within Calot's triangle and serves as an important landmark. - Its presence helps surgeons identify the **boundaries of the triangle** and assess for inflammation or malignancy related to the gallbladder. *Cystic artery* - The **cystic artery** is a consistent structure within Calot's triangle, typically arising from the **right hepatic artery**. - It is routinely **ligated during cholecystectomy** and is one of the key structures surgeons must identify within the triangle.

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: Elastic fibers of tunica media are secreted by

Smooth muscle. Correct: Smooth muscle - Smooth muscle cells within the tunica media are primarily responsible for synthesizing and secreting elastic fibers along with collagen and proteoglycans [1] - This extracellular matrix provides elasticity and structural integrity to blood vessels, allowing them to stretch and recoil with blood flow [1] - In elastic arteries (like the aorta), smooth muscle cells produce fenestrated elastic membranes that are characteristic of the tunica media Incorrect: Endothelium - Endothelial cells form the innermost lining of blood vessels (tunica intima) and are involved in regulating vascular tone, blood clotting, and inflammation [1] - They do not typically secrete the bulk of elastic fibers found in the tunica media Incorrect: External lamina - The external lamina (or external basal lamina) is an extracellular matrix layer, not a cellular component that secretes elastic fibers - It is actually secreted by the smooth muscle cells themselves and serves as structural support around individual muscle cells Incorrect: Fibroblast - Fibroblasts are connective tissue cells that primarily produce collagen and other extracellular matrix components in many tissues - While they contribute to the tunica adventitia (outermost layer), the tunica media's elastic fibers are primarily produced by smooth muscle cells [1]

Q: Which of the following statements is true regarding an epidural hematoma?

Between skull and dura mater. ***Between skull and dura mater*** - An **epidural (extradural) hematoma** occurs when bleeding accumulates in the **potential space between the skull and the dura mater** [1]. - More precisely, it forms between the **periosteal layer of dura** (adherent to skull) and the **meningeal layer of dura**, stripping the dura away from the skull. - This typically results from a tear in the **middle meningeal artery** following traumatic head injury, classically from a **temporal bone fracture**. - Classic presentation: **lucid interval** followed by deterioration with **biconvex (lentiform) appearance** on CT scan [1]. *Inside the brain* - Bleeding *inside the brain parenchyma* itself is an **intracerebral hemorrhage**, not an epidural hematoma. - Caused by hypertension, trauma, vascular malformations, or hemorrhagic stroke. - CT shows intraparenchymal blood collection, not extra-axial. *Between skull and outermost periosteal layer* - This is anatomically **not a potential space** since the periosteal layer of dura is **firmly adherent** to the inner table of the skull. - An epidural hematoma actually strips this periosteal layer *away* from the skull, creating the space. - This option is incorrectly phrased and anatomically impossible as stated. *Between scalp and outer skull layer* - Bleeding *between the scalp and outer skull surface* is a **subgaleal hematoma** (crosses suture lines) or **cephalhematoma** in neonates (limited by suture lines). - These are **extracranial** collections, superficial to the skull bones. - Completely different from an **intracranial** epidural hematoma.

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 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.

Question 1

B cells are located in which region of lymph nodes?

Accepted Answer

Cortical follicles

Answer

Paracortical region

Answer

Subcapsular region

Answer

Medullary sinuses

Question 2

Intercalated disc is present in:

Accepted Answer

Cardiac muscle

Answer

Smooth muscle

Answer

Skeletal muscle

Answer

All of the options

Question 3

Where do primitive red blood cells first originate during early embryonic development?

Accepted Answer

Yolk sac

Answer

Liver

Answer

Bone marrow

Answer

Spleen

Question 4

Which organ receives dual blood supply with both sources contributing to its primary metabolic function?

Accepted Answer

Liver

Answer

Heart

Answer

Kidney

Answer

Lung

Question 5

Which of the following structures does NOT pass through Calot's triangle?

Accepted Answer

Portal vein

Answer

Right hepatic artery

Answer

Lymph node of Lund

Answer

Cystic artery

Question 6

Sertoli cells are derived from -

Accepted Answer

Coelomic epithelium

Answer

Genital swelling

Answer

Primordial germ cells

Answer

Germinal epithelium

Question 7

Elastic fibers of tunica media are secreted by

Accepted Answer

Smooth muscle

Answer

Endothelium

Answer

External lamina

Answer

Fibroblast

Question 8

Which of the following statements is true regarding an epidural hematoma?

Accepted Answer

Between skull and dura mater

Answer

Inside the brain

Answer

Between skull and outermost periosteal layer

Answer

Between scalp and outer skull layer

Question 9

Seminal colliculus is present in ?

Accepted Answer

Urethra

Answer

Testis

Answer

Prostate

Answer

Scrotum

Question 10

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

NEET-PG 2015 — Anatomy