NEET-PG 2018 - Anatomy Practice Questions

Q: During acute tonsillitis, referred pain from the tonsil to the middle ear occurs via which nerve?

Glossopharyngeal nerve. ***Glossopharyngeal nerve*** - The **glossopharyngeal nerve (CN IX)** provides sensory innervation to the palatine tonsil via its tonsillar branches - CN IX also supplies the middle ear via the **tympanic nerve (Jacobson's nerve)**, which forms the tympanic plexus - This shared sensory pathway explains **referred otalgia** (ear pain) during acute tonsillitis - Inflammation of the tonsil stimulates CN IX, and the brain misinterprets this as pain from the middle ear *Facial nerve* - The **facial nerve (CN VII)** primarily provides motor innervation to muscles of facial expression and taste to the anterior two-thirds of the tongue - While it has a small sensory component (nervus intermedius) for the external auditory canal, it does not innervate the tonsil - Cannot serve as the pathway for referred pain from tonsil to middle ear *Trigeminal nerve* - The **trigeminal nerve (CN V)** provides sensory innervation to the face, anterior scalp, and oral cavity - Does not innervate the palatine tonsil or the middle ear cavity - Not involved in tonsillar referred otalgia *Vagus nerve* - The **vagus nerve (CN X)** provides sensory innervation to parts of the pharynx, larynx, and external auditory canal (via Arnold's nerve) - While it contributes to pharyngeal sensation, the **glossopharyngeal nerve is the primary pathway** for referred otalgia from tonsillar inflammation due to its direct innervation of both the tonsil and middle ear

Q: Testicular artery is a branch of -

Abdominal aorta. ***Abdominal aorta*** - The **testicular arteries**, also known as **gonadal arteries**, originate directly from the anterior aspect of the **abdominal aorta**. - They typically arise just inferior to the **renal arteries** at the level of the second lumbar vertebra (L2) and descend to supply the testes. *Common iliac artery* - The common iliac artery is a terminal branch of the **abdominal aorta**, but it gives rise to the internal and external iliac arteries, not directly the testicular artery. [2] - It bifurcates at the level of the sacroiliac joint. [3] *External iliac artery* - The external iliac artery primarily supplies the **lower limb** and gives off the inferior epigastric and deep circumflex iliac arteries. [1] - It does not directly provide branches to the testes. *Internal iliac artery* - The internal iliac artery primarily supplies the **pelvic organs**, gluteal region, and perineum. - While it has numerous branches, none of them are the main gonadal arteries; it contributes to the blood supply of the reproductive organs through other smaller branches. [3]

Q: The Gut blood vessel marked (Red arrow) in the angiogram is: (Recent NEET Pattern 2018-19)

Superior mesenteric artery. ***Superior mesenteric artery*** - The image shows an **abdominal angiogram** with a vessel arising from the anterior aspect of the aorta and branching extensively, consistent with the **superior mesenteric artery (SMA)**. - The SMA typically supplies the **midgut structures**, which include the duodenum (distal to the major duodenal papilla), jejunum, ileum, cecum, ascending colon, and the proximal two-thirds of the transverse colon. *Inferior mesenteric artery* - The **inferior mesenteric artery (IMA)** originates lower down the aorta, usually at the level of L3, and supplies the hindgut (distal one-third of the transverse colon, descending colon, sigmoid colon, and rectum). - The branching pattern and location in the angiogram do not match the expected origin and distribution of the IMA. *Splenic artery* - The **splenic artery** is a branch of the celiac trunk, which arises higher than the vessel shown and typically courses towards the left to supply the spleen, stomach, and pancreas. - Its branching pattern and location are distinctly different from the vessel highlighted in the image, which is clearly supplying mesenteric structures. *Gastroepiploic artery* - The **gastroepiploic arteries** (right and left) are branches primarily supplying the greater curvature of the stomach and the greater omentum. - These arteries are much smaller and are situated along the stomach, not originating directly from the aorta in this manner or having such a widespread mesenteric distribution.

Q: Which of the following layers contains Odland bodies?

B. ***B*** - The layer indicated by **B** is the **stratum granulosum**, which is characterized by the presence of **keratohyalin granules** and **Odland bodies** (lamellar bodies). - **Odland bodies** are crucial for forming the **epidermal water barrier** as they release lipids and enzymes into the intercellular space. *A* - The layer indicated by **A** is the **stratum corneum**, which consists of dead, flattened keratinocytes. - This layer is primarily involved in protection and does not contain Odland bodies, which are found in deeper layers. *C* - The layer indicated by **C** is the **stratum spinosum**, characterized by many **desmosomes** giving a "spiny" appearance. - While cells in this layer are metabolically active and produce keratin, Odland bodies primarily form and are extruded in the stratum granulosum. *D* - The layer indicated by **D** is the **stratum basale** (or stratum germinativum), the deepest layer of the epidermis. - This layer contains **stem cells** that are constantly dividing to replenish the epidermal layers and is also where melanocytes are located; it does not contain Odland bodies.

Q: Identify the function of the muscles marked in red:

Flexion at MCP joint. ***Flexion at MCP joint*** - The muscles shown in red are the **lumbricals**, which primarily function to **flex the metacarpophalangeal (MCP) joints** and **extend the interphalangeal (IP) joints**. - This is their most fundamental action when identifying lumbrical function, as they originate from **flexor digitorum profundus tendons** and insert into the **extensor expansion**, providing precise **MCP joint flexion**. - This unique action creates the **"lumbrical grip"** essential for precision handling. *Flexion at IP joint* - Lumbricals actually **extend the interphalangeal (IP) joints**, not flex them, making this option anatomically incorrect. - **Flexion at IP joints** is performed by the **flexor digitorum superficialis** (PIP joints) and **flexor digitorum profundus** (DIP joints). - The lumbrical insertion into the **extensor hood** produces IP extension, the opposite of this option. *Extension at MCP joint* - **Extension at the MCP joints** is primarily performed by the **extensor digitorum** and other **extrinsic extensor muscles**. - Lumbricals produce the opposite action, **flexing the MCP joints** rather than extending them. *Abduction at MCP joint* - **Abduction at the MCP joints** is primarily performed by the **dorsal interossei muscles** using the **DAB** (Dorsal ABduct) mnemonic. - Lumbricals do not contribute to **finger abduction** but rather focus on **MCP flexion, IP extension**, and **fine motor control**.

Q: Which is correct about structures marked as "X" found in smooth muscle?

Dense bodies. ***Dense bodies*** - The structures marked "X" are **dense bodies**, which are analogous to **Z-discs** in skeletal muscle, serving as attachment points for **actin filaments**. - They are crucial for transmitting the contractile force generated by the **actin-myosin bundles** to the cell membrane, leading to the characteristic corkscrew-like contraction of smooth muscle cells. *A band* - The **A band** is a region found in **striated muscle** (skeletal and cardiac muscle) where thick and thin filaments overlap, corresponding to the length of the myosin filaments. - Smooth muscle lacks the organized sarcomeric structure, and thus, **A bands** are not present. *Calmodulin* - **Calmodulin** is a calcium-binding protein that plays a key role in smooth muscle contraction by activating **myosin light chain kinase (MLCK)**. - However, it is a soluble protein involved in signaling, not a structural component like the dense bodies shown in the image. *H band* - The **H band** is located within the **A band** of a **sarcomere** in striated muscle, representing the central region where only thick (myosin) filaments are present. - Similar to the **A band**, the **H band** is a feature of striated muscle and is not found in the unstriated smooth muscle cells.

Q: Which of the following has maximum smooth muscle as compared to wall thickness?

A. ***A*** - Structure A represents a **terminal bronchiole**, which has the **maximum proportion of smooth muscle relative to wall thickness** among all respiratory structures. - Terminal bronchioles lack cartilage and respiratory epithelium (no alveoli), making smooth muscle the dominant structural component of their walls, comprising a high percentage of the total wall thickness. - This abundant smooth muscle allows for precise control of **bronchoconstriction** and **bronchodilation**, which is crucial for regulating air distribution to the respiratory zones. *B* - Structure B appears to be a **respiratory bronchiole** or an **alveolar duct**, which is more distal than terminal bronchioles and has less smooth muscle relative to its wall thickness. - As airways progress distally from terminal bronchioles toward the alveoli, smooth muscle gradually decreases as the primary function shifts from conduction and airflow regulation to gas exchange. - Respiratory bronchioles have alveoli budding from their walls, which reduces the proportion of smooth muscle in the overall wall structure. *C* - Structure C points to an **alveolar sac**, which is composed primarily of **alveoli** clustered together. Alveolar walls are extremely thin to facilitate efficient gas exchange and contain very little to no smooth muscle. - The function of alveoli is gas exchange, not airflow regulation, hence they lack the contractile elements like smooth muscle that are abundant in conducting airways. *D* - Structure D points to an **individual alveolus**, which is the primary site of gas exchange. Alveolar walls are extremely thin and consist of type I pneumocytes (for gas exchange), type II pneumocytes (surfactant production), and alveolar macrophages. - **Alveoli** lack smooth muscle entirely, as their structure is optimized for diffusion and not for active constriction or dilation.

Question 1

During acute tonsillitis, referred pain from the tonsil to the middle ear occurs via which nerve?

Accepted Answer

Glossopharyngeal nerve

Answer

Facial nerve

Answer

Trigeminal nerve

Answer

Vagus nerve

Question 2

Testicular artery is a branch of -

Accepted Answer

Abdominal aorta

Answer

Common iliac artery

Answer

External iliac artery

Answer

Internal iliac artery

Question 3

The Gut blood vessel marked (Red arrow) in the angiogram is: (Recent NEET Pattern 2018-19)

Accepted Answer

Superior mesenteric artery

Answer

Inferior mesenteric artery

Answer

Splenic artery

Answer

Gastroepiploic artery

Question 4

Which of the following layers contains Odland bodies?

Accepted Answer

B

Answer

A

Answer

C

Answer

D

Question 5

Identify the function of the muscles marked in red:

Accepted Answer

Flexion at MCP joint

Answer

Flexion at IP joint

Answer

Extension at MCP joint

Answer

Abduction at MCP joint

Question 6

Which is correct about structures marked as "X" found in smooth muscle?

Accepted Answer

Dense bodies

Answer

A band

Answer

Calmodulin

Answer

H band

Question 7

Which of the following has maximum smooth muscle as compared to wall thickness?

Accepted Answer

A

Answer

B

Answer

C

Answer

D

NEET-PG 2018 — Anatomy