INI-CET 2018 - Anatomy PYQs Practice Questions

Q: What is the action of the muscle marked with an arrow on the mandible?

Elevation of the mandible. ***Elevation of the mandible*** - The muscle indicated by the arrow is the **masseter muscle**, a powerful muscle of mastication. - The primary action of the **masseter** is to **elevate the mandible**, closing the mouth and clamping the teeth. *Lowering of the mandible* - Lowering (depression) of the mandible is primarily performed by the **lateral pterygoid**, digastric, geniohyoid, and mylohyoid muscles. - The **masseter** is directly responsible for the opposite action of elevation. *Pulling back of the mandible* - Pulling back, or **retrusion**, of the mandible is mainly performed by the posterior fibers of the **temporalis muscle** and the suprahyoid muscles. - The **masseter** has a more vertical orientation, making it ineffective for retrusion. *Pushing forward of the mandible* - Pushing forward, or **protrusion**, of the mandible is primarily carried out by the **lateral pterygoid** and medial pterygoid muscles. - The **masseter's** main fibers are not oriented to produce a significant protrusive force. [Practice more Anatomy PYQs on OnCourse]

Q: Cranial nerve that is involved in olfaction:

Trigeminal. ***Trigeminal*** - The **trigeminal nerve (CN V)** carries sensory information from the face and contributes to olfactory perception through its **ophthalmic (V1) and maxillary (V2) divisions** [1]. - These divisions detect **chemical irritants, pungency, cooling, and warming sensations** in the nasal cavity (chemesthesis), contributing to the overall perception of smells. - Examples include the stinging sensation of **ammonia**, cooling of **menthol**, and burning of **capsaicin** - all part of the smell experience. - This is distinct from true olfaction (CN I) but is an essential component of how we perceive "smell" in daily life. *Hypoglossal* - The **hypoglossal nerve (CN XII)** is purely a **motor nerve** that controls the intrinsic and extrinsic muscles of the **tongue**. - It is essential for **speech, swallowing, and tongue movement** but has **no role in olfaction or smell perception**. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** mediates **taste sensation from the posterior third of the tongue**, swallowing, and salivation. - While important for taste, it has **no role in olfactory pathways or smell detection**. *Vagus* - The **vagus nerve (CN X)** has extensive **parasympathetic functions** and carries taste sensation from the **epiglottis and pharynx**. - It innervates thoracic and abdominal organs but is **not involved in olfactory perception**. [Practice more Anatomy PYQs on OnCourse]

Q: Identify the inheritance pattern shown below.

X linked recessive. ***X linked recessive*** - The pattern shows that mainly **males are affected**, and the trait skips generations (e.g., individual I-1 is unaffected, but his children are affected). - Affected fathers (like II-3) do not pass the trait to their sons, but their daughters are carriers and can pass it on to their sons (like IV-1). *Y linked recessive* - In Y-linked inheritance, only **males would be affected**, and all sons of an affected father would inherit the trait. - This pedigree shows unaffected fathers having affected sons, and not all sons of affected males are affected directly. *X linked dominant* - In X-linked dominant inheritance, affected fathers pass the trait to **all their daughters**, and at least one parent would be affected in each generation. - This pedigree shows skipping of generations and affected individuals being born to unaffected parents (e.g., II-3 and III-5). *Y linked dominant* - Y-linked inheritance, whether dominant or recessive, would only affect **males** and would be directly passed from father to all sons. - The pedigree shows unaffected parents having affected offspring (e.g., I-1 and I-2 produced II-3), which rules out Y-linked inheritance. [Practice more Anatomy PYQs on OnCourse]

Q: Occlusion of blood supply of the area marked in red will lead to all of the following except:

Apraxia (Constructional). ***Apraxia (Constructional)*** - The area marked in red represents the **medial portion of the precentral gyrus (motor cortex)** and **postcentral gyrus (sensory cortex)**, as well as the **paracentral lobule**, which are supplied by the **anterior cerebral artery (ACA)**. - Constructional apraxia is typically associated with **posterior parietal lobe lesions**, particularly in the non-dominant hemisphere, which is supplied by the posterior cerebral artery and middle cerebral artery branches, not the ACA. *Urinary incontinence* - The **paracentral lobule**, located in the area supplied by the ACA (marked in red), contains centers for **bladder control** and voluntary micturition. - Damage to this region can lead to **urinary incontinence** due to disrupted cortical control over bladder function. *Rectal incontinence* - Similar to bladder control, the **paracentral lobule** also plays a role in **voluntary bowel control**. - Ischemia in this region due to ACA occlusion can therefore result in **rectal incontinence**. *Peri-anal anaesthesia* - The **somatosensory cortex** representing the lower limbs and perineum is located in the **paracentral lobule** (postcentral gyrus part). - Occlusion of the ACA, supplying this region, can lead to **sensory deficits**, including **anaesthesia** in the peri-anal area. [Practice more Anatomy PYQs on OnCourse]

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. [Practice more Anatomy PYQs on OnCourse]

Question 1

What is the action of the muscle marked with an arrow on the mandible?

Accepted Answer

Elevation of the mandible

Answer

Lowering of the mandible

Answer

Pulling back of the mandible

Answer

Pushing forward of the mandible

Question 2

Cranial nerve that is involved in olfaction:

Accepted Answer

Trigeminal

Answer

Hypoglossal

Answer

Glossopharyngeal

Answer

Vagus

Question 3

Identify the inheritance pattern shown below.

Accepted Answer

X linked recessive

Answer

Y linked recessive

Answer

X linked dominant

Answer

Y linked dominant

Question 4

Occlusion of blood supply of the area marked in red will lead to all of the following except:

Accepted Answer

Apraxia (Constructional)

Answer

Urinary incontinence

Answer

Rectal incontinence

Answer

Peri-anal anaesthesia

Question 5

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 6

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 7

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

Accepted Answer

Elevation

Answer

Depression

Answer

Protraction

Answer

Retraction

Question 8

Identify the part of the duodenum marked below:

Accepted Answer

2nd part

Answer

1st part

Answer

3rd part

Answer

4th part

Question 9

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 10

Nucleus pulposus develops from: (AIIMS May 2018)

Accepted Answer

C

Answer

A

Answer

B

Answer

D

INI-CET 2018 — Anatomy