INI-CET 2018 Practice Questions

Q: Identify the marked layer in the given histological section.

Inner plexiform layer. ***Inner plexiform layer*** - The arrow points to a **synaptic layer** characterized by a dense network of **axons, dendrites**, and synapses between bipolar cells, amacrine cells, and ganglion cells. - This layer is distinguished by its **reticular appearance** and its position between the inner nuclear layer (nuclei of bipolar, amacrine, and horizontal cells) and the ganglion cell layer. *Outer plexiform layer* - This layer is located more externally in the retina, between the **outer nuclear layer** and the **inner nuclear layer**. - It is where photoreceptors (rods and cones) synapse with bipolar and horizontal cells. *Inner limiting layer* - The **innermost layer** of the retina, adjacent to the vitreous humor. - It is a thin, acellular membrane formed by the basal laminae of the Müller cells. *Outer limiting layer* - This layer is situated internally to the **photoreceptor layer** (rods and cones). - It is not a true membrane but rather a series of intercellular junctions (adherens junctions) between photoreceptor cells and Müller cells.

Q: Identify the type of connective tissue present in the area marked with the arrow.

Dense irregular. ***Dense irregular*** - The image shows bundles of **collagen fibers** arranged haphazardly in various directions, which is characteristic of dense irregular connective tissue. - This tissue type provides **strength and resistance to stress** from multiple directions, typical of the **dermis** of the skin or organ capsules. *Loose and irregular* - **Loose connective tissue** has a much higher proportion of ground substance and fewer, thinner, and loosely arranged fibers compared to what is shown in the image. - While it is also irregular, the **density of the collagen fibers** in the marked area is inconsistent with loose connective tissue. *Specialised* - **Specialized connective tissues** include cartilage, bone, blood, and adipose tissue, which have distinct cellular and extracellular matrix components not depicted here. - The tissue shown is primarily characterized by its fibrous composition, not specialized cells or matrix elements like those in bone or cartilage. *Dense regular* - **Dense regular connective tissue** is characterized by collagen fibers densely packed and arranged in parallel bundles, providing strength in one direction. - Examples include **tendons and ligaments**, which are not found in this arrangement beneath the epithelium as suggested by the image.

Q: What is the action of the muscle marked in the given image?

Elevation. ***Elevation*** - The image shows a coronal section of the head, and the arrow points to the **temporalis muscle**, which is one of the primary muscles of mastication. - The main action of the temporalis muscle is to **elevate the mandible**, closing the mouth. - The **anterior and middle fibers** particularly produce elevation. *Depression* - Depression of the mandible is primarily performed by the **lateral pterygoid muscle** and the suprahyoid muscles (e.g., digastric, geniohyoid). - The temporalis muscle's fiber orientation is not consistent with mandibular depression. *Protraction* - **Protraction** (protrusion) of the mandible is primarily carried out by the **lateral pterygoid muscles** (bilateral contraction). - The temporalis muscle does not contribute significantly to protraction. *Retraction* - **Retraction** of the mandible is indeed performed by the **posterior fibers of the temporalis muscle**. - However, since the question asks about the action of the muscle as shown in the image (likely showing the entire muscle or its anterior portion), and the **primary and most prominent action** of the temporalis as a whole is **elevation**, this is the best answer.

Q: Identify the part of the duodenum marked below:

2nd part. ***2nd part*** - The image shows the duodenum making a C-shaped curve around the head of the pancreas. The arrow points to the descending portion which directly receives secretions. - The **major duodenal papilla**, where the common bile duct and pancreatic duct empty, is located in the posteromedial wall of the **descending (second) part of the duodenum**. *1st part* - The first part, or superior part, is the shortest and widest part of the duodenum. It ascends from the pylorus and is mostly peritoneal. - It lies superior to the head of the pancreas, unlike the segment indicated by the arrow. *3rd part* - The third part, or horizontal (inferior) part, passes horizontally to the left, anterior to the inferior vena cava and aorta. - It is located inferior to the head of the pancreas and superior mesenteric vessels. *4th part* - The fourth part, or ascending part, ascends on the left side of the aorta to the duodenojejunal flexure. - This segment is typically located to the left of the vertebral column and is continuous with the jejunum.

Q: Which nerve gives sensory supply to the region marked with an arrow?

Radial nerve. ***Radial nerve*** - The image shows the **dorsal (back) aspect of the hand**, specifically the region over the **anatomical snuffbox** or the dorsal part of the thumb and first web space. - The **superficial branch of the radial nerve** provides sensory innervation to this area, including the dorsal aspect of the thumb, index, and half of the middle finger, extending to the dorsal hand. *Median nerve* - The **median nerve** primarily provides sensory innervation to the **palmar aspect** of the lateral three and a half digits (thumb, index, middle, and radial half of the ring finger) and the corresponding palm. - It does not innervate the dorsal hand in the region indicated. *Ulnar nerve* - The **ulnar nerve** innervates the **medial 1.5 digits** (pinky and ulnar half of the ring finger) on both the palmar and dorsal aspects of the hand, as well as the ulnar part of the palm and dorsum of the hand. - The highlighted region is on the radial side of the hand, not the ulnar side. *Posterior interosseous nerve* - The **posterior interosseous nerve** is a **motor nerve** that innervates the muscles in the posterior compartment of the forearm. - It does **not provide sensory innervation** to any part of the hand.

Q: Nucleus pulposus develops from: (AIIMS May 2018)

C. ***Correct Option C*** - Label C points to the **notochord**, which is the embryonic structure that the **nucleus pulposus** of the intervertebral discs develops from. - The notochord provides transient axial support during early embryonic development and induces the formation of the neural tube. - During development, most of the notochord degenerates, but remnants persist as the gelatinous core of intervertebral discs. *Incorrect Option A* - Label A indicates the **neural tube**, which develops into the **brain and spinal cord**. - It arises from the neural plate, which is induced by the underlying notochord. - The neural tube does not contribute to the intervertebral disc structure. *Incorrect Option B* - Label B represents the **secondary yolk sac**, a structure involved in early nutrient transfer and the formation of primordial germ cells. - It does not directly contribute to the formation of musculoskeletal structures like the nucleus pulposus. *Incorrect Option D* - Label D points to the **ectoderm**, the outermost germ layer, which gives rise to the epidermis, nervous system (including the neural tube), and sensory organs. - While it forms the neural tube, it does not directly form the nucleus pulposus or other mesodermal derivatives.

Q: A young patient with absent thymus presents with tetany and hypoparathyroidism. Which of the following is a marked area in the picture defective in this condition?

C. ***C*** - The image shows the **pharyngeal arches and pouches** during embryonic development. **C** points to the **third pharyngeal pouch**, which gives rise to the **thymus** and inferior parathyroid glands. - A defect in the development of the third pharyngeal pouch would lead to an **absent or hypoplastic thymus** and **hypoparathyroidism**, causing symptoms like tetany due to hypocalcemia. This condition is known as **DiGeorge syndrome**. *A* - **A** points to the first pharyngeal pouch, which develops into the **auditory tube** and **tympanic cavity**. - Defects in the first pharyngeal pouch would primarily affect structures in the ear, not the thymus or parathyroid glands. *B* - **B** points to the fourth pharyngeal pouch, which gives rise to the **superior parathyroid glands** and the **ultimobranchial body** (parafollicular C cells of the thyroid). - While hypoparathyroidism could be involved, the primary defect in DiGeorge syndrome affects the third pouch, leading to both thymic and parathyroid issues more comprehensively. *D* - **D** points to the first pharyngeal arch, which contributes to the formation of the **mandible**, **maxilla**, and several muscles of mastication. - Defects in the first pharyngeal arch are associated with conditions like **Treacher Collins syndrome** or **Pierre Robin sequence**, which present with facial dysmorphism rather than thymic or parathyroid agenesis.

Q: Which of the following structures of the scapula is palpable in infraclavicular fossa?

C. ***C - Coracoid Process*** - The **coracoid process** is a hook-like bony projection from the superior border of the scapula that extends anteriorly and laterally. - It is located approximately **2.5 cm below the lateral third of the clavicle** in the **infraclavicular fossa** (also called the deltopectoral triangle). - The coracoid process is the **only structure of the scapula that is palpable anteriorly** in the infraclavicular fossa, making it an important surgical landmark. - It can be felt by deep palpation in the infraclavicular region, just medial to the deltoid muscle. *A - Glenoid Cavity* - The glenoid cavity is the shallow, pear-shaped articular surface on the lateral angle of the scapula that receives the head of the humerus. - It is deeply positioned and completely covered by the humeral head and surrounding soft tissues (rotator cuff muscles, joint capsule). - It is **not palpable** from any surface location, including the infraclavicular fossa. *B - Acromion* - The acromion is the lateral continuation of the spine of the scapula, forming the highest point of the shoulder. - It articulates with the lateral end of the clavicle at the acromioclavicular joint. - The acromion is palpable at the **tip of the shoulder laterally**, not in the infraclavicular fossa which is located more medially and anteriorly. - It forms part of the superior boundary of the shoulder region, well lateral to the infraclavicular fossa. *D - Inferior Angle of Scapula* - The inferior angle is the lowest point of the scapula, located at approximately the level of the 7th rib or T7 vertebra. - It is palpable on the **posterior thoracic wall**, particularly when the arm is moved. - It is located posteriorly and inferiorly, nowhere near the anterior infraclavicular fossa.

Q: Mandibular division of trigeminal nerve passes through which of the following? (AIIMS May 2018)

D. ***D*** - The label 'D' points to the **foramen ovale**, which is the opening through which the **mandibular division of the trigeminal nerve (V3)** exits the middle cranial fossa. - The foramen ovale also transmits the **accessory meningeal artery**, **lesser petrosal nerve**, and the **emissary veins**. *A* - The label 'A' points to the **foramen rotundum**, which is primarily for the passage of the **maxillary division of the trigeminal nerve (V2)**. - The foramen rotundum is distinct from the foramen ovale and is located more anterior and medial. *B* - The label 'B' points to the **foramen spinosum**, which allows the passage of the **middle meningeal artery** and the **nervus spinosus (meningeal branch of V3)**. - While it transmits a branch of V3, it is not the main exit point for the entire mandibular division. *C* - The label 'C' points to the **foramen lacerum**, which is occupied by **cartilage** in vivo and primarily traversed by the **internal carotid artery** and its accompanying sympathetic plexus passing superiorly to it. - No major cranial nerves pass completely through it; instead, some nerves (like the greater petrosal nerve) pass over its superior surface or exit through associated canals.

Q: Which disease occurs due to involvement of the structure marked in red? (AIIMS May 2018)

Paralysis agitans. ***Paralysis agitans*** - The red circle points to the **substantia nigra**, a key brain structure involved in producing **dopamine**. - **Paralysis agitans**, also known as **Parkinson's disease**, is characterized by the degeneration of dopaminergic neurons in the substantia nigra, leading to motor symptoms like tremor, rigidity, and bradykinesia. *Depression* - Depression is a mood disorder associated with imbalances in various **neurotransmitters** (e.g., serotonin, norepinephrine, dopamine) and often involves brain regions such as the prefrontal cortex and limbic system, not primarily the substantia nigra. - While dopamine pathways can be implicated in motivation and reward, the primary pathology of major depression is not direct degeneration of the substantia nigra. *Alzheimer's disease* - Alzheimer's disease is a neurodegenerative disorder primarily characterized by the accumulation of **amyloid plaques** and **neurofibrillary tangles**, leading to neuronal loss and brain atrophy, particularly in the hippocampus and cerebral cortex, not the substantia nigra. - It results in progressive **memory loss** and cognitive decline, distinct from the motor symptoms seen in Parkinson's. *Huntington's chorea* - Huntington's chorea is a hereditary neurodegenerative disease caused by the degeneration of GABAergic neurons in the **striatum** (caudate and putamen). - It is characterized by **involuntary movements** (chorea), cognitive decline, and psychiatric symptoms, which result from basal ganglia dysfunction but not specifically originating from the substantia nigra.

Question 1

Identify the marked layer in the given histological section.

Accepted Answer

Inner plexiform layer

Answer

Outer plexiform layer

Answer

Inner limiting layer

Answer

Outer limiting layer

Question 2

Identify the type of connective tissue present in the area marked with the arrow.

Accepted Answer

Dense irregular

Answer

Loose and irregular

Answer

Specialised

Answer

Dense regular

Question 3

What is the action of the muscle marked in the given image?

Accepted Answer

Elevation

Answer

Depression

Answer

Protraction

Answer

Retraction

Question 4

Identify the part of the duodenum marked below:

Accepted Answer

2nd part

Answer

1st part

Answer

3rd part

Answer

4th part

Question 5

Which nerve gives sensory supply to the region marked with an arrow?

Accepted Answer

Radial nerve

Answer

Median nerve

Answer

Ulnar nerve

Answer

Posterior interosseous nerve

Question 6

Nucleus pulposus develops from: (AIIMS May 2018)

Accepted Answer

C

Answer

A

Answer

B

Answer

D

Question 7

A young patient with absent thymus presents with tetany and hypoparathyroidism. Which of the following is a marked area in the picture defective in this condition?

Accepted Answer

C

Answer

B

Answer

D

Answer

A

Question 8

Which of the following structures of the scapula is palpable in infraclavicular fossa?

Accepted Answer

C

Answer

A

Answer

B

Answer

D

Question 9

Mandibular division of trigeminal nerve passes through which of the following? (AIIMS May 2018)

Accepted Answer

D

Answer

A

Answer

B

Answer

C

Question 10

Which disease occurs due to involvement of the structure marked in red? (AIIMS May 2018)

Accepted Answer

Paralysis agitans

Answer

Depression

Answer

Alzheimer's disease

Answer

Huntington's chorea

INI-CET 2018

Anatomy