Which is derived from Wolffian duct?
Podocytes are seen in -
Bronchogenic sequestration is seen in which lobe?
In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?
Renal papilla opens into -
Inferior parathyroid develops from which pharyngeal pouch?
Skeletal derivative of 2nd pharyngeal arch -
Which of the following is derived from endoderm?
Which of the following is a traction epiphysis ?
What anatomical structures are involved in the closure of the fossa ovalis?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 71: Which is derived from Wolffian duct?
- A. Appendix of epididymis (Correct Answer)
- B. Appendix of the testis
- C. Uterine structure
- D. Hydatid of Morgagni
Explanation: The **appendix of the epididymis** is a vestigial structure directly derived from the mesonephric (Wolffian) duct in males. It is an embryological remnant of this duct, located at the head of the epididymis. *Appendix of the testis* - The **appendix of the testis** (hydatid of Morgagni) is a remnant of the paramesonephric (Müllerian) duct, not the Wolffian duct. - It is usually found on the upper pole of the testis, typically near the epididymis. *Uterine structure* - **Uterine structures** (uterus, fallopian tubes, and upper vagina) are derived from the paramesonephric (Müllerian) ducts in females [1]. - The Wolffian ducts largely regress in females due to the absence of testosterone. *Hydatid of Morgagni* - The term **hydatid of Morgagni** can refer to the appendix of the testis (Müllerian duct remnant) or, less commonly, to the appendix of the epididymis (Wolffian duct remnant). - However, in common clinical and anatomical usage, it almost exclusively refers to the **appendix of the testis**, which is a Müllerian duct derivative.
Question 72: Podocytes are seen in -
- A. Bowman's capsule (Correct Answer)
- B. Proximal convoluted tubule
- C. Distal convoluted tubule
- D. Collecting tubule of the kidney
Explanation: **Bowman's capsule** - **Podocytes** are specialized epithelial cells that form the **visceral layer** of Bowman's capsule. They have foot processes (pedicels) that interdigitate to form slit diaphragms, which are crucial for the **filtration barrier** of the glomerulus [1]. - These cells facilitate the selective passage of water and small solutes from the blood into Bowman's space, while preventing the filtration of large proteins and blood cells. *Proximal convoluted tubule* - The **proximal convoluted tubule** is primarily involved in the **reabsorption** of essential nutrients, ions, and water from the filtrate back into the bloodstream [1]. - Its cells are characterized by a **brush border** (microvilli) and numerous mitochondria, indicating high metabolic activity, and are not podocytes [1]. *Distal convoluted tubule* - The **distal convoluted tubule** plays a role in fine-tuning the reabsorption of ions and water, under the influence of hormones like **aldosterone** and **ADH**. - Its cells lack the specialized foot processes and filtration function characteristic of podocytes. *Collecting tubule of the kidney* - The **collecting tubule** (or collecting duct) is involved in regulating water reabsorption and acid-base balance, responding to **ADH** to concentrate urine. - Its epithelial cells are principal cells and intercalated cells, which are different in structure and function from podocytes.
Question 73: Bronchogenic sequestration is seen in which lobe?
- A. Left lower lobe (Correct Answer)
- B. Right upper lobe
- C. Left upper lobe
- D. Right middle lobe
Explanation: ***Left lower lobe*** - **Bronchopulmonary sequestration**, particularly the **intralobar type**, most commonly affects the **posterior basal segment of the left lower lobe**. [1] - This congenital malformation involves a segment of lung tissue that lacks normal communication with the tracheobronchial tree and receives its blood supply from a systemic artery. [1] *Right upper lobe* - While sequestration can occur anywhere, the **right upper lobe** is a much less common location for bronchopulmonary sequestration compared to the lower lobes. - Sequestration in the upper lobes is rare and usually associated with specific anatomical variations. *Right middle lobe* - The **right middle lobe** is also an infrequent site for bronchopulmonary sequestration. - The typical presentation involves the basal segments of the lower lobes due to embryonic developmental patterns. *Left upper lobe* - **Left upper lobe** involvement in bronchopulmonary sequestration is uncommon. - The majority of cases are found in the lower lobes, especially the left lower lobe.
Question 74: In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?
- A. Adductor muscles
- B. Quadriceps
- C. Gluteus medius and minimus (Correct Answer)
- D. Gluteus maximus
Explanation: ***Gluteus medius and minimus*** - The **gluteus medius** and **gluteus minimus** are essential **abductors** of the hip, primarily responsible for stabilizing the pelvis during the **single-limb support phase of gait**. - When one leg is lifted during walking, these muscles on the **stance leg side** contract to prevent the pelvis from tilting downwards on the unsupported swing leg side. *Adductor muscles* - **Adductor muscles** (adductor longus, brevis, magnus, pectineus, gracilis) primarily function to bring the thigh toward the midline of the body. - While they play a role in gait stability, their main action is not to prevent the lateral pelvic tilt described. *Quadriceps* - The quadriceps femoris group (rectus femoris, vastus lateralis, medialis, intermedius) are powerful **extensors of the knee**. - They are crucial for weight acceptance and propulsion during walking but do not directly prevent lateral pelvic tilt [1]. *Gluteus maximus* - The **gluteus maximus** is the largest and most powerful muscle of the hip, primarily responsible for **hip extension** and **external rotation**. - It is crucial for activities like climbing stairs or running, but its main role in normal walking is not to prevent lateral pelvic tilt; that function is more specific to the gluteus medius and minimus.
Question 75: Renal papilla opens into -
- A. Cortex
- B. Pyramid
- C. Minor calyx (Correct Answer)
- D. Major calyx
Explanation: ***Minor calyx*** - The **renal papilla** is the apex of the renal pyramid, which drains urine directly into a **minor calyx**. - Minor calyces then merge to form major calyces, eventually leading to the renal pelvis. *Cortex* - The **renal cortex** is the outer layer of the kidney, containing glomeruli and convoluted tubules, and does not directly receive urine from the papilla. - Urine is primarily formed and filtered in the cortex and then flows into the medulla. *Pyramid* - A **renal pyramid** is a conical structure within the renal medulla, and the renal papilla is its tip, but it doesn't open *into* the pyramid itself. - Instead, the pyramid *contains* the structures that contribute to the papilla. *Major calyx* - A **major calyx** is formed by the convergence of several minor calyces. - The renal papilla drains into the minor calyx, which then, in turn, drains into the major calyx.
Question 76: Inferior parathyroid develops from which pharyngeal pouch?
- A. 1st
- B. 2nd
- C. 3rd (Correct Answer)
- D. 4th
Explanation: The inferior parathyroid glands develop from the dorsal wing of the third pharyngeal pouch. Due to their origin, they often migrate further caudally than the superior parathyroid glands, sometimes even locating within the thymus which also develops from the third pouch. *1st* - The first pharyngeal pouch contributes to the formation of the eustachian tube, tympanic cavity, and mastoid air cells. - It has no role in the development of the parathyroid glands. *2nd* - The second pharyngeal pouch mainly gives rise to the palatine tonsils and their crypts. - It is not involved in the development of parathyroid tissue. *4th* - The fourth pharyngeal pouch gives rise to the superior parathyroid glands and the parafollicular cells (C cells) of the thyroid, which produce calcitonin. - While it forms parathyroid tissue, it is for the superior glands, not the inferior ones.
Question 77: Skeletal derivative of 2nd pharyngeal arch -
- A. Malleus
- B. Incus
- C. Stapes (Correct Answer)
- D. Maxilla
Explanation: ***Stapes*** - The **2nd pharyngeal arch** (also known as the hyoid arch) gives rise to several structures, including Reichert's cartilage, which forms the **stapes** bone, the styloid process, the lesser horn of the hyoid, and the upper part of the hyoid body. - Its muscles include the **stapedius**, stylohyoid, posterior belly of the digastric, and muscles of facial expression. *Malleus* - The **malleus** is derived from the **1st pharyngeal arch** (Meckel's cartilage), along with the incus. - The 1st pharyngeal arch is also responsible for forming the malleus, incus, and mandible. *Incus* - Similar to the malleus, the **incus** also originates from the **1st pharyngeal arch** (Meckel's cartilage). - Both the malleus and incus are crucial components of the middle ear ossicles but are structurally distinct from the stapes. *Maxilla* - The **maxilla** development is primarily from the **maxillary prominence** of the first pharyngeal arch, which is a subdivision of the first arch but does not originate from the 2nd arch. - It forms a significant portion of the midface and upper jaw, contributing to the nasal cavity and orbital floor.
Question 78: Which of the following is derived from endoderm?
- A. Gall bladder (Correct Answer)
- B. Lens
- C. Spleen
- D. Lymph nodes
Explanation: ***Gall bladder*** - The **gallbladder**, along with other organs of the **gastrointestinal tract** such as the liver, pancreas, and epithelial lining of the digestive and respiratory systems, originates from the **endoderm** [1]. - The endoderm forms the primitive gut tube, from which these accessory digestive organs bud off. *Lens* - The **lens of the eye** is derived from the **surface ectoderm**, which invaginates to form the lens vesicle. - This contrasts with the neural ectoderm, which forms the neural tube and retina. *Spleen* - The **spleen** is derived from the **mesoderm**, specifically from mesenchymal cells in the dorsal mesentery of the stomach. - It is involved in blood filtration and immune responses, making it a lymphoid organ. *Lymph nodes* - **Lymph nodes** are primarily derived from the **mesoderm**, specifically from specialized mesenchymal cells that form their connective tissue capsule and stroma. - The immune cells within the lymph nodes, such as lymphocytes, originate from hematopoietic stem cells that migrate into these developing structures.
Question 79: Which of the following is a traction epiphysis ?
- A. Tibial condyles
- B. Head of femur
- C. Trochanter of femur
- D. Coracoid process of scapula (Correct Answer)
Explanation: ***Coracoid process of scapula*** - A **traction epiphysis** (also called atavistic epiphysis) serves as an attachment site for muscles and tendons, transferring muscle force to the bone without bearing significant weight or forming articular surfaces. - The **coracoid process** is a classic example, anchoring the **pectoralis minor, coracobrachialis, and short head of biceps brachii**, as well as important ligaments (coracoclavicular and coracoacromial). - It develops from a separate ossification center purely for muscle and ligament attachment, not for articulation or weight-bearing. *Tibial condyles* - The **tibial condyles** are **pressure epiphyses** (articular epiphyses) that form the superior articular surface of the tibia. - They articulate with the femoral condyles to form the knee joint and bear significant weight during standing and movement. - Their primary function is joint formation and contribution to longitudinal bone growth. *Trochanter of femur* - The **greater and lesser trochanters** are large bony prominences that serve as muscle attachment sites, but they are better classified as **apophyses** rather than true traction epiphyses. - An **apophysis** is a secondary ossification center that does not contribute to longitudinal bone growth and serves primarily for muscle attachment. - While functionally similar to traction epiphyses, the term "traction epiphysis" is more specifically applied to structures like the coracoid process, tibial tuberosity, and calcaneal tuberosity. *Head of femur* - The **head of femur** is a classic **pressure epiphysis** that articulates with the acetabulum to form the hip joint. - It bears significant body weight and contributes to the longitudinal growth of the femur. - Its primary functions are joint formation and weight transmission, not muscle attachment.
Question 80: What anatomical structures are involved in the closure of the fossa ovalis?
- A. Septum primum + Endocardial cushion
- B. Septum primum + Septum secundum (Correct Answer)
- C. Endocardial cushions + Septum secundum
- D. None of the options
Explanation: The septum primum acts as a valve, closing against the septum secundum postnatally due to changes in atrial pressure. This fusion effectively closes the foramen ovale, leading to the formation of the fossa ovalis. The endocardial cushions are important for the formation of the atrial and ventricular septa, as well as the AV valves, but not directly for the closure of the fossa ovalis. The septum primum is directly involved, but its apposition with the endocardial cushions doesn't close the foramen ovale. While both structures contribute to heart development, their direct interaction is not responsible for the closure of the fossa ovalis. The septum secundum forms the muscular rim of the fossa ovalis, and the endocardial cushions are critical for atrial septation, but not the final closure here. This option is incorrect because the specific combination of septum primum and septum secundum is indeed responsible for the closure of the fossa ovalis.