NEET-PG 2012 - Anatomy Practice Questions

Q: Pancreas divisum indicates which of the following?

Failure of fusion of dorsal & ventral pancreatic buds. ***Failure of fusion of dorsal & ventral pancreatic buds*** - **Pancreas divisum** is a congenital anomaly where the **dorsal and ventral pancreatic buds fail to fuse** during embryonic development [1]. - This results in the **bulk of the pancreas (dorsal bud)** draining through the **accessory pancreatic duct** into the minor duodenal papilla, while the ventral bud drains via the main pancreatic duct [1]. *Duplication of the pancreas* - This condition involves the presence of **multiple, distinct pancreatic tissues**, which is different from pancreas divisum where the existing buds simply do not fuse. - Pancreas divisum is a failure of fusion of two normally formed buds, not the formation of extra pancreatic tissue. *Formation of more than two pancreatic buds* - Normal embryonic development typically involves two pancreatic buds (dorsal and ventral), not more than two [1]. - The issue in pancreas divisum is with the **fusion process**, not the number of initial buds [1]. *Formation of only one pancreatic bud* - Pancreatic development normally involves **two distinct buds (dorsal and ventral)** [1]. - The formation of only one bud would lead to pancreatic agenesis or severe hypoplasia, which is a different anomaly than pancreas divisum.

Q: Corpora arenacea is seen in?

Pineal. ***Pineal*** - **Corpora arenacea**, also known as **brain sand**, are calcium deposits found in the pineal gland. - Their presence is a normal, age-related finding and increases with age, though their exact physiological role is not fully understood. *Prostate* - The prostate gland contains **corpora amylacea**, which are concentric calcifications found within the glandular acini. - While similar in appearance to corpora arenacea, they are distinct structures specific to the prostate. *Seminal vesicle* - The seminal vesicles produce a fluid component of semen, and while they may occasionally show calcifications, these are typically due to stones or chronic inflammation, not the characteristic "brain sand" seen in the pineal gland. - They do not contain corpora arenacea as a normal physiological feature. *Breast* - Calcifications in the breast are common and can be either benign (e.g., **fibrocystic changes**, vascular calcifications) or malignant (e.g., **ductal carcinoma in situ**). - These calcifications are generally not referred to as corpora arenacea and have different clinical implications and microscopic appearances.

Q: Primary and secondary palates are divided by

Incisive foramen. ***Incisive foramen*** - The **incisive foramen** is an anatomical landmark located just posterior to the central incisors, and it marks the boundary between the developmentally distinct primary and secondary palates. - The **primary palate** develops from the median palatine process, while the **secondary palate** develops from the palatal shelves of the maxillary prominences [1]. *Greater palatine foramen* - The **greater palatine foramen** is located near the posterior border of the hard palate, transmitting the greater palatine nerve and vessels. - It lies within the **secondary palate** and does not delineate the boundary between the primary and secondary palatal structures. *Canine teeth* - The **canine teeth** are part of the dental arch and play a role in mastication. - While located in the anterior part of the oral cavity, they are not a developmental or anatomical boundary marker for palatal divisions [1]. *Alveolar arch* - The **alveolar arch** is the bone that supports the teeth, forming the curved ridge of the maxilla and mandible [1]. - It is distinct from the palate and does not serve as a divider between the primary and secondary palatal components.

Q: Which structure is not seen at the L3 level?

Coeliac trunk. ***Coeliac trunk*** - The **coeliac trunk** typically arises from the abdominal **aorta** at the level of **T12-L1**, which is significantly higher than L3. - It then immediately branches into the **left gastric**, **splenic**, and **common hepatic arteries** to supply foregut structures. *Iliac vessels* - The **common iliac arteries** and veins typically bifurcate from the **aorta** and **IVC** around the L4-L5 level. - Their presence, or the start of their formation, can be observed near or just above **L3**, depending on individual anatomical variation and how "at the L3 level" is interpreted (e.g., within the L3 vertebral body's span). *Aorta* - The **abdominal aorta** descends along the posterior abdominal wall and is a prominent structure at the **L3 level**. - It typically bifurcates into the common iliac arteries at the level of **L4**, meaning it is still a large, undivided vessel at L3. *IVC* - The **inferior vena cava (IVC)** ascends through the abdomen and is a significant vascular structure at the **L3 level**. - It is formed by the union of the common iliac veins at the level of **L5** and continues superiorly.

Q: Ophthalmic artery is a branch of:

Cerebral part of ICA. ***Cerebral part of ICA*** - The **ophthalmic artery** is typically the first major branch off the **internal carotid artery (ICA)** once it exits the cavernous sinus and enters the cranial cavity. - This segment of the ICA is also known as the supraclinoid or **cerebral part**, underscoring its proximity to the brain. *Cavernous part of ICA* - The **cavernous part of the ICA** is located within the cavernous sinus and typically gives off smaller branches such as the **meningohypophyseal trunk** and the **inferolateral trunk**, which supply structures within and around the sinus. - The ophthalmic artery emerges after the ICA exits the cavernous sinus, not from within it. *MCA* - The **middle cerebral artery (MCA)** is a major terminal branch of the internal carotid artery, supplying large parts of the cerebrum. - It does not give rise to the ophthalmic artery, which branches off the ICA before the ICA bifurcates into the MCA and anterior cerebral artery. *Facial artery* - The **facial artery** is a branch of the **external carotid artery**, supplying structures of the face. - The ophthalmic artery is a primary supply to the orbit and is derived from the internal carotid artery, a completely separate vascular system.

Q: Which muscle stabilizes the clavicle during movement of the shoulder?

Subclavius. ***Subclavius*** - The **subclavius muscle** originates from the first rib and inserts into the inferior surface of the clavicle, acting to **depress the clavicle** and prevent its displacement, thus enhancing shoulder stability during movement. - It plays a crucial role in protecting the underlying **neurovascular structures** (brachial plexus and subclavian vessels) from external trauma to the shoulder. *Pectoralis major* - This large, fan-shaped muscle primarily functions in **adduction, medial rotation, and flexion of the humerus** at the shoulder joint [1]. - It does not directly stabilize the clavicle but rather acts on the arm. *Latissimus dorsi* - The **latissimus dorsi** is a broad muscle of the back responsible for **extension, adduction, and internal rotation of the humerus** [1]. - Its actions are mainly on the humerus and it does not directly stabilize the clavicle. *Serratus anterior* - The **serratus anterior** muscle primarily **protracts and rotates the scapula**, keeping it pressed against the thoracic wall. - While it's essential for **scapular stability** and overhead arm movements, it does not directly stabilize the clavicle.

Q: What is the classification of the Y chromosome?

Submetacentric. ***Submetacentric*** - The **Y chromosome** is classified as submetacentric because its **centromere** is located off-center, resulting in two arms of unequal length. - The short arm (Yp) is smaller than the long arm (Yq), but not as disproportionate as in acrocentric chromosomes. - The **X chromosome** is also submetacentric, making both sex chromosomes belong to this category. *Metacentric* - A **metacentric chromosome** has its **centromere** located in the middle, resulting in two arms of approximately equal length. - Examples include chromosomes 1, 3, 16, 19, and 20, which have nearly equal arm ratios unlike the Y chromosome. *Acrocentric* - An **acrocentric chromosome** has its **centromere** located very close to one end, creating one very short arm and one very long arm. - The five acrocentric human chromosomes are **13, 14, 15, 21, and 22**, which possess satellite DNA and nucleolar organizing regions (NORs) on their short arms. - The **Y chromosome is NOT acrocentric** despite historical confusion; it has a more centrally positioned centromere than true acrocentric chromosomes. *None of the options* - This option is incorrect because the Y chromosome has a specific and well-established classification as **submetacentric** based on its centromere position and arm ratio.

Q: All are derived from ectoderm except for which of the following?

Adrenal cortex. ***Adrenal cortex*** - The adrenal cortex is derived from the **intermediate mesoderm**, specifically from the cells lining the posterior abdominal wall. The cells migrate to develop into the adrenal cortex. - It produces various steroid hormones, including **aldosterone**, **cortisol**, and **androgens**, which regulate diverse bodily functions. *Lens of the eye* - The lens of the eye is derived from the **surface ectoderm**. It forms from an invagination of the surface ectoderm called the lens placode. - Its primary function is to **focus light** onto the retina. *Hair follicles* - Hair follicles develop from the **surface ectoderm** [1]; they are invaginations of the epidermis that extend into the dermis. - They produce hair, which provides **insulation** and **protection** [1]. *Nails* - Nails are also derivatives of the **surface ectoderm**, forming thickened plates on the dorsal surface of the distal phalanges. - They provide **protection** to the fingertips and aid in grasping objects.

Q: Which structures are located anterior to the transverse sinus?

Aorta. ***Aorta*** - The **transverse sinus of the pericardium** is a passage within the pericardial cavity that separates the great arteries (aorta and pulmonary trunk) anteriorly from the atria and great veins posteriorly. - The **ascending aorta** and **pulmonary trunk** are both located anterior to the transverse sinus. - This anatomical relationship is clinically important during cardiac surgery, as the transverse sinus can be used to pass ligatures around the great vessels. *Right atrium* - The **right atrium** is located posterior to the transverse sinus. - It forms part of the posterior wall of the pericardial cavity and receives the superior and inferior venae cavae. - The transverse sinus separates the atria from the anteriorly positioned great arteries. *Left atrium* - The **left atrium** is also positioned posterior to the transverse sinus. - It forms the base of the heart and receives the pulmonary veins. - Like the right atrium, it lies behind the plane of the transverse sinus. *Right pulmonary artery* - The **right pulmonary artery** is a branch of the pulmonary trunk that passes to the right lung. - While the **pulmonary trunk** itself is anterior to the transverse sinus, the **right pulmonary artery** branch courses laterally and posteriorly, passing behind the ascending aorta and superior vena cava. - Therefore, the right pulmonary artery is NOT considered anterior to the transverse sinus in the same way the main great vessels (aorta and pulmonary trunk) are.

Q: What is the typical length of a human sperm cell?

55 micrometers. ***55 micrometers*** - A typical **human sperm cell** measures approximately **55 micrometers** from the head to the tip of the tail [1]. - This length allows for efficient motility and navigation within the female reproductive tract to reach the ovum [1]. *100 micrometers* - This length is significantly **longer** than the average size of a human sperm cell. - While some cells can achieve this size, it is not typical for **spermatozoa**. *65 micrometers* - Although closer to the actual size, **65 micrometers** is generally considered slightly larger than the average human sperm cell length. - Sperm length is critical for understanding their **mobility** and **fertility** [1]. *50 micrometers* - This measurement is slightly **shorter** than the typical length of a human sperm cell. - The precise length, including the **head** and **flagellum**, contributes to its function.

Question 1

Pancreas divisum indicates which of the following?

Accepted Answer

Failure of fusion of dorsal & ventral pancreatic buds

Answer

Duplication of the pancreas

Answer

Formation of more than two pancreatic buds

Answer

Formation of only one pancreatic bud

Question 2

Corpora arenacea is seen in?

Accepted Answer

Pineal

Answer

Seminal vesicle

Answer

Breast

Answer

Prostate

Question 3

Primary and secondary palates are divided by

Accepted Answer

Incisive foramen

Answer

Greater palatine foramen

Answer

Canine teeth

Answer

Alveolar arch

Question 4

Which structure is not seen at the L3 level?

Accepted Answer

Coeliac trunk

Answer

Iliac vessels

Answer

Aorta

Answer

IVC

Question 5

Ophthalmic artery is a branch of:

Accepted Answer

Cerebral part of ICA

Answer

Cavernous part of ICA

Answer

MCA

Answer

Facial artery

Question 6

Which muscle stabilizes the clavicle during movement of the shoulder?

Accepted Answer

Subclavius

Answer

Pectoralis major

Answer

Latissimus dorsi

Answer

Serratus anterior

Question 7

What is the classification of the Y chromosome?

Accepted Answer

Submetacentric

Answer

Metacentric

Answer

Acrocentric

Answer

None of the options

Question 8

All are derived from ectoderm except for which of the following?

Accepted Answer

Adrenal cortex

Answer

Hair follicles

Answer

Nails

Answer

Lens of the eye

Question 9

Which structures are located anterior to the transverse sinus?

Accepted Answer

Aorta

Answer

Right atrium

Answer

Left atrium

Answer

Right pulmonary artery

Question 10

What is the typical length of a human sperm cell?

Accepted Answer

55 micrometers

Answer

50 micrometers

Answer

100 micrometers

Answer

65 micrometers

NEET-PG 2012 — Anatomy