Anatomy
6 questionsWhich statement accurately describes a characteristic of synovial joints?
Right ovarian artery is a branch of ?
Azygos vein drains into:
In which region of the human spine is the number of vertebrae usually constant?
All the following are characteristics of the oculomotor nerve except:
Which of the following is NOT a branch of 1st part of maxillary artery?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 331: Which statement accurately describes a characteristic of synovial joints?
- A. Hyaline cartilage covers the articular surfaces of synovial joints. (Correct Answer)
- B. The metacarpo-phalangeal joint is a condyloid joint.
- C. Cartilage can sometimes divide the joint into two cavities.
- D. Stability is inversely proportional to mobility in synovial joints.
Explanation: ***Hyaline cartilage covers the articular surfaces of synovial joints.*** - The articular surfaces of bones within a **synovial joint** are covered by a thin layer of **hyaline cartilage**, providing a smooth, low-friction surface for movement [1]. - This **articular cartilage** absorbs shock and protects the underlying bone from wear and tear [1]. - This is a **universal structural characteristic** of all synovial joints, making it the most accurate answer. *The metacarpo-phalangeal joint is a condyloid joint.* - While this statement is factually true (MCP joints are indeed **condyloid/ellipsoid joints** allowing movement in two planes), it describes a **specific type** of synovial joint, not a general characteristic of all synovial joints. - The question asks for a characteristic that describes synovial joints as a category, not an example of one specific joint classification. - This makes it incorrect as the best answer to this question. *Cartilage can sometimes divide the joint into two cavities.* - This statement refers to an **articular disc** or **meniscus**, which is a fibrocartilaginous structure that can partially or completely divide a synovial joint cavity. - This feature is present in **some** synovial joints (like the knee or temporomandibular joint) but is **not universal**. - Since it's not a characteristic of all synovial joints, it's not the best answer. *Stability is inversely proportional to mobility in synovial joints.* - Generally, there is an **inverse relationship** between **stability** and **mobility** in joints; joints designed for great mobility (e.g., shoulder) tend to be less stable, and vice-versa (e.g., hip). - However, this describes a **functional principle** or trade-off rather than a **structural characteristic** that defines synovial joints. - While true, it's not the defining characteristic being asked for in this question.
Question 332: Right ovarian artery is a branch of ?
- A. Abdominal aorta (Correct Answer)
- B. Right internal iliac
- C. Common iliac
- D. External iliac
Explanation: ***Abdominal aorta*** - The **right ovarian artery** typically originates directly from the **abdominal aorta**, just inferior to the renal arteries [1]. - This is a direct branch, supplying blood to the **right ovary**, **fallopian tube**, and surrounding structures [1]. *Right internal iliac* - The **internal iliac artery** primarily supplies the **pelvic organs**, gluteal region, and medial thigh [1]. - While it has branches to pelvic structures, the ovarian artery does not originate from it. *Common iliac* - The **common iliac artery** bifurcates into the **internal and external iliac arteries** at the level of the sacroiliac joint. - It does not directly give off the ovarian artery. *External iliac* - The **external iliac artery** continues as the **femoral artery** below the inguinal ligament, primarily supplying the lower limb. - It does not give off branches to the ovary.
Question 333: Azygos vein drains into:
- A. Left brachiocephalic vein
- B. Inferior vena cava
- C. Superior vena cava (Correct Answer)
- D. Right brachiocephalic vein
Explanation: Wait, what? Azygos vein drains into: ***Superior vena cava*** - The **azygos vein** ascends along the right side of the vertebral column and typically arches over the root of the right lung before draining into the **superior vena cava (SVC)**. - This anatomical arrangement allows the azygos system to collect venous blood from the posterior thoracic and abdominal walls, as well as the bronchi and esophagus, ultimately returning it to the systemic circulation via the SVC [1]. *Left brachiocephalic vein* - The **left brachiocephalic vein** drains blood from the upper left limb and left side of the head and neck. - It merges with the right brachiocephalic vein to form the SVC; the azygos vein does not directly drain into it. *Inferior vena cava* - The **inferior vena cava (IVC)** collects deoxygenated blood from the lower body. - The azygos system primarily drains structures above the diaphragm, distinct from the IVC's drainage area. *Right brachiocephalic vein* - The **right brachiocephalic vein** drains blood from the upper right limb and right side of the head and neck. - While it contributes to the formation of the SVC, the azygos vein's direct connection is to the SVC itself, not the right brachiocephalic vein.
Question 334: In which region of the human spine is the number of vertebrae usually constant?
- A. Cervical (Correct Answer)
- B. Thoracic
- C. Lumbar
- D. Sacral
Explanation: ***Cervical*** - The human cervical spine almost universally consists of **seven vertebrae (C1-C7)**, making it the most constant region in terms of vertebral number. - This consistent number is crucial for normal neck movement and protection of vital neurological structures. *Thoracic* - While typically having **12 vertebrae**, variations in the thoracic region can occur, with some individuals having 11 or 13 due to transitional vertebrae. - These variations are less common but indicate that the number is not as strictly constant as in the cervical spine. *Lumbar* - The lumbar spine commonly has **five vertebrae (L1-L5)**, but variations such as four or six lumbar vertebrae can be seen due to lumbarization or sacralization. - **Lumbarization** involves the first sacral segment detaching, while **sacralization** involves the fifth lumbar vertebra fusing with the sacrum. *Sacral* - The sacrum is formed by the fusion of **five sacral vertebrae (S1-S5)**, but the number of *individual identifiable* vertebrae before fusion, or in cases of incomplete fusion, can vary. - The sacral region itself is a fused structure, and while it originates from five segments, the concept of "number of vertebrae" can be ambiguous due to its characteristic fusion.
Question 335: All the following are characteristics of the oculomotor nerve except:
- A. Carries parasympathetic nerve fibres
- B. Supplies inferior oblique muscle
- C. Enters orbit through the inferior orbital fissure (Correct Answer)
- D. Enters orbit through the superior orbital fissure
Explanation: ***Enters orbit through the inferior orbital fissure*** - The oculomotor nerve **does not** enter the orbit through the **inferior orbital fissure**; it enters via the **superior orbital fissure**. - The **inferior orbital fissure** transmits structures like the **maxillary nerve (V2)**, **zygomatic nerve**, and **inferior ophthalmic vein**. *Carries parasympathetic nerve fibres* - The oculomotor nerve contains **parasympathetic preganglionic fibers** that synapse in the **ciliary ganglion** [1]. - These fibers control **pupillary constriction** (via the **sphincter pupillae**) and **accommodation** (via the **ciliary muscle**) [1]. *Supplies inferior oblique muscle* - The **inferior oblique muscle** is one of the **extraocular muscles** innervated by the **oculomotor nerve (CN III)** [2]. - This muscle works to **elevate** and **externally rotate** the eye [2]. *Enters orbit through the superior orbital fissure* - The oculomotor nerve indeed passes through the **superior orbital fissure** to enter the orbit. - This fissure serves as the passage for several cranial nerves and vessels, including the **oculomotor (III)**, **trochlear (IV)**, **abducens (VI)**, and branches of the **ophthalmic nerve (V1)**.
Question 336: Which of the following is NOT a branch of 1st part of maxillary artery?
- A. Accessory meningeal artery
- B. Inferior alveolar artery
- C. Middle meningeal artery
- D. Greater palatine artery (Correct Answer)
Explanation: ***Greater palatine artery*** - This artery is a branch of the **third part** of the maxillary artery, which supplies the palate. - The third part of the maxillary artery (also known as the pterygopalatine part) gives off branches that pass through the pterygopalatine fossa. *Middle meningeal artery* - This is a significant branch of the **first part** of the maxillary artery, entering the cranial cavity via the **foramen spinosum** to supply the dura mater. - It is often injured in head trauma, leading to an **epidural hematoma**. *Accessory meningeal artery* - This artery also arises from the **first part** of the maxillary artery and enters the skull through the **foramen ovale** to supply the dura mater. - It is a smaller branch compared to the middle meningeal artery. *Inferior alveolar artery* - It is a branch of the **first part** of the maxillary artery, descending to enter the mandible via the **mandibular foramen** to supply the teeth and bone of the mandible. - It gives off the **mylohyoid branch** before entering the mandibular foramen.
Physiology
3 questionsPeripheral and central chemoreceptors may both contribute to the increased ventilation that occurs as a result of which of the following?
Which of the following components are included in microcirculation?
Mean arterial pressure is calculated as:
NEET-PG 2012 - Physiology NEET-PG Practice Questions and MCQs
Question 331: Peripheral and central chemoreceptors may both contribute to the increased ventilation that occurs as a result of which of the following?
- A. A decrease in arterial oxygen content
- B. A decrease in arterial blood pressure
- C. An increase in arterial carbon dioxide tension (Correct Answer)
- D. A decrease in arterial oxygen tension
Explanation: ***An increase in arterial carbon dioxide tension*** - An increase in **arterial PCO2** (hypercapnia) leads to a rapid decrease in the **pH of the cerebrospinal fluid (CSF)**, which strongly stimulates **central chemoreceptors** in the medulla. - While overwhelmingly driven by central chemoreceptors, a significant increase in **arterial PCO2** also causes a slight decrease in **arterial pH**, which can additionally stimulate **peripheral chemoreceptors** in the carotid and aortic bodies, leading to increased ventilation. *A decrease in arterial oxygen content* - A decrease in **arterial oxygen content** (e.g., due to anemia or carbon monoxide poisoning) without a significant drop in **arterial PO2** primarily affects oxygen delivery to tissues. - It does not directly stimulate peripheral chemoreceptors, which are sensitive to **PO2**, not content, nor does it affect central chemoreceptors directly to increase ventilation in this manner. *A decrease in arterial blood pressure* - A decrease in **arterial blood pressure** is sensed by **baroreceptors** and primarily triggers cardiovascular reflexes (e.g., increased heart rate and vasoconstriction) to restore blood pressure. - It does not directly stimulate peripheral or central chemoreceptors to significantly increase ventilation unless severe hypoperfusion leads to significant changes in arterial blood gases. *A decrease in arterial oxygen tension* - A decrease in **arterial oxygen tension (PO2)**, especially when it falls below approximately 60 mmHg, acts as a potent stimulus for **peripheral chemoreceptors**. - However, **central chemoreceptors** are primarily sensitive to **PCO2** and CSF pH, and a decrease in **arterial PO2** alone has little direct effect on their activity.
Question 332: Which of the following components are included in microcirculation?
- A. Capillaries
- B. Aorta
- C. Arteries and veins
- D. Capillaries, venules, and arterioles (Correct Answer)
Explanation: ***Capillaries, venules, and arterioles*** - **Microcirculation** is the portion of the **circulatory system** that includes the **smallest blood vessels**, specifically the **arterioles**, **capillaries**, and **venules**. - These vessels are crucial for the **delivery of oxygen** and **nutrients** to tissues and the removal of waste products. *Capillaries* - While **capillaries** are a vital part of **microcirculation** and the primary site of nutrient and waste exchange, they alone do not encompass the entire microcirculatory unit. - The microcirculation also includes the vessels that feed into and drain from the capillaries: the **arterioles** and **venules**. *Aorta* - The **aorta** is the **largest artery** in the body, part of the **macrocirculation**, which distributes blood from the heart to the systemic circulation. - It is not considered part of the **microcirculation** due to its large size and primary function as a high-pressure conduit rather than a site of exchange. *Arteries and veins* - **Arteries** and **veins** are primarily components of the **macrocirculation**, responsible for transporting blood to and from the systemic and pulmonary circuits. - While arterioles and venules (small arteries and veins) are part of the microcirculation, the broader terms "arteries" and "veins" typically refer to the larger vessels and do not exclusively define the microcirculatory network.
Question 333: Mean arterial pressure is calculated as:
- A. (DBP+3SBP)/2
- B. (SBP+3DBP)/2
- C. (DBP+2SBP)/3
- D. (SBP+2DBP)/3 (Correct Answer)
Explanation: ***(SBP+2DBP)/3*** - This formula accurately calculates **mean arterial pressure (MAP)**, emphasizing the longer duration of diastole compared to systole in the cardiac cycle. - The diastolic blood pressure (**DBP**) is weighted twice as much as the systolic blood pressure (**SBP**) to reflect this physiological difference. *(DBP+2SBP)/3* - This formula incorrectly weighs the diastolic pressure less and the systolic pressure more, which does not reflect the **physiological duration of the cardiac cycle**. - While it attempts to average pressures, it does not correctly represent the **mean perfusion pressure**. *(SBP+3DBP)/2* - This formula is inaccurate for calculating MAP as the **denominator should be 3**, not 2, to account for the three components being averaged (one SBP and two DBP). - It also disproportionately weights **DBP** too high relative to the standard physiological formula. *(DBP+3SBP)/2* - This formula is incorrect as it applies an **excessive weighting to SBP** and uses an incorrect denominator. - It would yield a significantly higher and inaccurate value for **mean arterial pressure**.
Surgery
1 questionsWhat is the appropriate treatment for an incidentally detected appendicular carcinoid tumor measuring 2.5 cm?
NEET-PG 2012 - Surgery NEET-PG Practice Questions and MCQs
Question 331: What is the appropriate treatment for an incidentally detected appendicular carcinoid tumor measuring 2.5 cm?
- A. Right hemicolectomy (Correct Answer)
- B. Limited resection of the right colon
- C. Total colectomy
- D. Appendicectomy
Explanation: ***Right hemicolectomy*** - An appendiceal carcinoid tumor **larger than 2 cm** (or with **mesoappendix invasion, positive margins, or high-grade features**) warrants a right hemicolectomy due to a significantly higher risk of lymph node metastasis (20-30%). - This 2.5 cm tumor clearly exceeds the 2 cm threshold, making right hemicolectomy the standard of care. - This procedure ensures adequate oncological margins and removal of regional lymph nodes, which is crucial for complete treatment. *Limited resection of the right colon* - This option is insufficient for an appendiceal carcinoid of this size, as it may not remove all regional lymph nodes or provide adequate oncological margins. - Limited resection lacks the systematic lymphadenectomy required for tumors exceeding 2 cm. *Total colectomy* - This is an **overly aggressive** and unnecessary procedure for an isolated appendiceal carcinoid tumor, even one of this size. - Total colectomy is typically reserved for diffuse colonic involvement, multifocal tumors, or specific genetic syndromes, which is not indicated here. *Appendicectomy* - An appendicectomy alone is only appropriate for very small appendiceal carcinoid tumors, typically **less than 1 cm** in size, with negative margins and without evidence of mesoappendix invasion or aggressive features. - For a 2.5 cm tumor, the risk of regional lymph node involvement (20-30%) is too high for appendicectomy to be considered adequate oncological treatment.