Anatomy
5 questionsWhich is derived from Wolffian duct?
Renal papilla opens into -
Coronary sinus develops from?
What anatomical structures are involved in the closure of the fossa ovalis?
Which of the following is a traction epiphysis ?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 241: 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 242: 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 243: Coronary sinus develops from?
- A. Truncus arteriosus
- B. Conus
- C. Sinus venosus (Correct Answer)
- D. AV canal
Explanation: Sinus venosus - The sinus venosus is a primordial cardiac chamber that receives venous blood from the body and placenta in the early embryonic heart. - The left horn of the sinus venosus loses its connection with the systemic venous circulation and becomes the coronary sinus, which drains most of the cardiac veins into the right atrium [1, 4]. Truncus arteriosus - The truncus arteriosus is the embryonic precursor to the ascending aorta and pulmonary trunk. - It does not contribute to the development of the coronary sinus. Conus - The conus (or conus cordis) is the outflow portion of the primitive ventricle and differentiates into the outflow tracts of the right (infundibulum) and left (aortic vestibule) ventricles. - It is not involved in the formation of the coronary sinus. AV canal - The atrioventricular (AV) canal connects the primitive atrium and ventricle and is crucial for the formation of the AV valves and septation of the heart chambers. - It does not directly develop into the coronary sinus.
Question 244: 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.
Question 245: 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.
Biochemistry
1 questionsWhat is the net number of ATP molecules and NADH formed in glycolysis per glucose molecule?
NEET-PG 2012 - Biochemistry NEET-PG Practice Questions and MCQs
Question 241: What is the net number of ATP molecules and NADH formed in glycolysis per glucose molecule?
- A. 4 ATP, 2 NADH
- B. 4 ATP, 4 NADH
- C. 2 ATP, 4 NADH
- D. 2 ATP, 2 NADH (Correct Answer)
Explanation: **2 ATP, 2 NADH** - Glycolysis has a net yield of **2 molecules of ATP** because 4 ATP molecules are produced, but 2 ATP molecules are consumed during the initial energy investment phase. - **2 molecules of NADH** are also produced during the energy generation phase when glyceraldehyde-3-phosphate is oxidized. *4 ATP, 2 NADH* - While 4 ATP molecules are indeed produced during glycolysis, this option does not account for the **2 ATP molecules consumed** in the initial steps, leading to an incorrect net value. - The production of **2 NADH** is correct, but the ATP count is the gross rather than the net. *4 ATP, 4 NADH* - This option overstates the production of both ATP and NADH. While **4 ATP are produced (gross)**, the net is 2 ATP. - Only **2 NADH** molecules are formed per glucose molecule in glycolysis, not 4. *2 ATP, 4 NADH* - This option accurately reflects the **net ATP yield of 2 molecules**. - However, it exaggerates the production of NADH, as only **2 molecules of NADH** are formed during glycolysis, not 4.
Obstetrics and Gynecology
1 questionsBlastocyst makes contact with endometrium on ?
NEET-PG 2012 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 241: Blastocyst makes contact with endometrium on ?
- A. < 3 days
- B. 5 - 7 days (Correct Answer)
- C. 8 - 11 days
- D. 15-16 days
Explanation: ***5-7 days*** - The **blastocyst makes initial contact** (apposition) with the **endometrium** around **day 5-6 after fertilization**. - **Implantation**, which includes adhesion and invasion, typically begins around day 6 and is complete by day 10. - This timeframe allows the blastocyst to travel from the fallopian tube to the uterus and for the uterine lining to be optimally prepared. *< 3 days* - Within the first few days after fertilization, the zygote is still undergoing **cleavage** and development into a **morula**, then a young blastocyst, while traveling down the fallopian tube. - It has not yet reached the uterus or developed sufficiently to interact with the endometrium. *8-11 days* - By 8-11 days, the process of implantation is usually **well underway or completed**, with the blastocyst already invading the endometrial wall. - Initial contact and attachment occur prior to this period. *15-16 days* - This timeframe is well beyond the typical window for initial blastocyst contact and implantation. - By 15-16 days post-fertilization, the embryo would be undergoing **gastrulation** and early organogenesis, assuming successful implantation.
Orthopaedics
1 questionsWhich of the following conditions can cause locking of the knee joint?
NEET-PG 2012 - Orthopaedics NEET-PG Practice Questions and MCQs
Question 241: Which of the following conditions can cause locking of the knee joint?
- A. Osgood Schlatter
- B. Tuberculosis of knee
- C. a and b both
- D. Loose body in knee joint (Correct Answer)
Explanation: ***Loose body in knee joint*** - A **loose body** (e.g., a fragment of cartilage or bone) can get trapped between the articular surfaces of the knee joint, mechanically obstructing its movement and causing sudden, painful **locking**. - This mechanical impingement prevents full extension or flexion of the knee until the loose body shifts, leading to episodic locking symptoms. *Osgood Schlatter* - This condition involves inflammation and potential avulsion of the **tibial tuberosity** where the patellar tendon inserts. - It primarily causes pain and swelling below the kneecap, especially during physical activity, but does not typically result in true mechanical locking of the joint. *Tuberculosis of knee* - **Tuberculosis of the knee joint** is an infectious arthritis that causes chronic pain, swelling, and gradual destruction of articular cartilage and bone. - While it can lead to pain and limited range of motion, it usually does not present with the sudden, intermittent mechanical locking characteristic of a loose body. *a and b both* - Neither **Osgood Schlatter** nor **Tuberculosis of the knee** typically cause the characteristic mechanical locking sensation described for a loose body in the joint. - Each of these conditions has distinct pathophysiological mechanisms and clinical presentations that do not involve a physical obstruction causing locking.
Physiology
2 questionsWhich isotope is used to measure RBC volume?
Which mechanism is primarily responsible for the transport of glucose in renal tubular cells?
NEET-PG 2012 - Physiology NEET-PG Practice Questions and MCQs
Question 241: Which isotope is used to measure RBC volume?
- A. Cr 51 (Correct Answer)
- B. H-3
- C. D2O
- D. I-135
Explanation: ***Cr 51*** - **Chromium-51** attaches irreversibly to the beta chain of hemoglobin, making it an ideal tracer for measuring **red blood cell volume** and survival. - After injection, the labeled red blood cells distribute throughout the circulation, and their dilution allows for the calculation of the total **RBC mass**. *H-3* - **Tritium (H-3)** is typically used as tritiated water to measure **total body water**, as it readily equilibrates throughout all fluid compartments. - It does not specifically bind to red blood cells for mass measurement. *D2O* - **D2O (heavy water)** is used to measure **total body water** content, similar to tritiated water. - It exchanges with water in the body and diffuses into all fluid compartments, rather than targeting red blood cells. *I-135* - While various **iodine isotopes** are used in medicine, such as **I-131** for thyroid imaging or therapy, **I-135** is not a commonly used isotope for measuring red blood cell volume. - Other tracers like **radio-iodinated human serum albumin** (e.g., I-125 HSA) can be used to measure plasma volume, not specifically RBC volume.
Question 242: Which mechanism is primarily responsible for the transport of glucose in renal tubular cells?
- A. Facilitated diffusion
- B. Glucose diffusion
- C. Sodium antiport
- D. Sodium-glucose cotransport (Correct Answer)
Explanation: ***Sodium-glucose cotransport*** - Glucose reabsorption in the renal tubules, particularly in the **proximal tubule**, occurs primarily via **secondary active transport** involving **sodium-glucose cotransporters (SGLTs)**. - SGLT proteins use the **sodium concentration gradient** (maintained by the Na+/K+-ATPase on the basolateral membrane) to move glucose against its concentration gradient from the tubular lumen into the cell. *Glucose diffusion* - While passive diffusion may play a minor role, it is insufficient to reabsorb the large amounts of **filtered glucose** - Diffusion would lead to significant **glucose loss in urine**, even at normal blood glucose levels. *Sodium antiport* - Antiport systems move two different ions or molecules in **opposite directions** across a membrane. - While present in renal cells, sodium antiport mechanisms are not the primary means of **glucose reabsorption**; rather, glucose transport is mostly symport. *Facilitated diffusion* - Facilitated diffusion involves carrier proteins (like **GLUT transporters**) that move molecules down their **concentration gradient**. - While GLUT transporters are present on the **basolateral membrane** of tubular cells to move glucose into the interstitium, they are not the primary mechanism for glucose uptake from the tubular lumen, which occurs against a concentration gradient.