Histology Practice Questions

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.

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: The image shows histological section of cerebellum. Identify the structures labeled in the image:

Three layers of cerebellar cortex. ***Three layers of cerebellar cortex (Correct Answer)*** - The image shows a classic histological section of the **cerebellar cortex** with its three distinct layers: - **Molecular layer** (outer) - contains dendrites of Purkinje cells and parallel fibers - **Purkinje cell layer** (middle) - contains large Purkinje cell bodies (clearly visible) - **Granular layer** (inner) - densely packed small granule cells - This is a standard cortical section showing the superficial architecture of the cerebellum *Deep nuclei of cerebellum (Incorrect)* - The deep cerebellar nuclei (dentate, emboliform, globose, fastigial) are embedded within the **white matter** of the cerebellum - They would NOT be visible in this superficial cortical section - Deep nuclei require sections through the cerebellar white matter to visualize *Layers of cerebral cortex (Incorrect)* - Cerebral cortex has **six layers**, not three - The cellular organization is distinctly different from cerebellar cortex - Purkinje cells are pathognomonic of cerebellum, not cerebrum *Basal ganglia (Incorrect)* - Basal ganglia are subcortical nuclei (caudate, putamen, globus pallidus) - They have a nuclear architecture, not layered cortical structure - Completely different histological appearance

Q: Identify the cell in the given histological image which does not migrate from the base of the crypt to ends of villi: (Recent NEET Pattern 2016-17)

Paneth cell. ***Paneth cell*** - **Paneth cells** are located at the base of the intestinal crypts and play a crucial role in innate immunity by secreting **antimicrobial peptides** (e.g., defensins) and **lysozyme**. - Unlike other intestinal epithelial cells that continuously proliferate and migrate upwards to the villi tips, Paneth cells are **long-lived** and remain stationary at the base of the crypt, acting as guardians of the stem cell niche. *Goblet cell* - **Goblet cells** are mucin-secreting cells that are relatively short-lived and **migrate from the crypts** towards the villi tips, continuously replaced. - They are responsible for producing **mucus** that protects the intestinal lining and aids in lubrication. *Oxyntic cell* - **Oxyntic cells**, also known as **parietal cells**, are found in the **gastric glands** of the stomach, not in the intestinal crypts or villi. - They are responsible for secreting **hydrochloric acid** and intrinsic factor, critical for digestion and vitamin B12 absorption. *Chief cell* - **Chief cells** (or peptic cells) are primarily located in the **gastric glands** of the stomach, secreting **pepsinogen** and gastric lipase. - They are not typically found in the intestinal crypts or villi and therefore do not participate in migration within the intestinal epithelium.

Q: Which of the following is Paneth cell?

4. ***Option 4 - Paneth Cells (Correct)*** - The cells indicated by **4** are located at the base of the intestinal crypts and are characterized by their prominent, brightly **eosinophilic (red-staining) granules** in the cytoplasm. - These **Paneth cells** secrete antimicrobial peptides and enzymes, such as **lysozyme and alpha-defensins**, which contribute to the innate immune defense of the intestinal lumen. *Option 1 - Lumen* - The arrow labeled **1** points to the **lumen** of the small intestine, which is the internal space within the villi and crypts. - This area is typically lined by **absorptive enterocytes** and goblet cells. *Option 2 - Intestinal Crypts* - The structures indicated by **2** are the **intestinal crypts (of Lieberkühn)**, which are glandular invaginations of the intestinal epithelium. - These crypts contain various cell types, including stem cells, enteroendocrine cells, and Paneth cells, but **2** specifically highlights the entire crypt structure rather than a single cell type. *Option 3 - Columnar Epithelial Cells* - The arrow labeled **3** points to an area occupied by **columnar epithelial cells**, likely **absorptive enterocytes** within the intestinal crypt. - These cells primarily function in nutrient absorption and do not exhibit the characteristic granular appearance of Paneth cells.

Q: Name the epithelium shown in the picture:

Pseudostratified columnar epithelium. ***Pseudostratified columnar epithelium*** - The image distinctly shows nuclei at **varying levels** within the epithelial layer, giving the false impression of multiple layers, characteristic of **pseudostratified epithelium**. - All cells rest on the **basement membrane**, but not all reach the apical surface, creating the pseudostratified appearance. - The cells themselves appear taller than they are wide, indicating a **columnar morphology**. *Simple cuboidal epithelium* - This type of epithelium is characterized by cells that are roughly **cube-shaped**, meaning their height and width are approximately equal. - The cells in the image are clearly taller than they are wide, ruling out cuboidal morphology. - Nuclei in simple cuboidal epithelium are typically **centrally located at the same level**, not at varying heights as seen here. *Simple ciliated columnar epithelium* - This would show a **single layer** of tall columnar cells with nuclei at the **same level** (typically basal), unlike the multiple nuclear levels seen in this image. - While pseudostratified columnar epithelium can also be ciliated (e.g., respiratory epithelium), the key distinguishing feature here is the **pseudostratification** pattern. - Simple columnar epithelium lacks the characteristic appearance of nuclei at varying heights that creates the false multilayered impression. *Transitional epithelium* - **Transitional epithelium** is typically found in the urinary tract and is characterized by its ability to stretch, with cells that can appear dome-shaped or umbrella-like in the superficial layer. - The cells in the image do not exhibit the characteristic **stratification** with distinct basal, intermediate, and superficial layers typical of transitional epithelium. - The uniform columnar appearance and nuclear arrangement rule out transitional epithelium.

Q: Identify the epithelium shown in the picture.

Transitional, Urinary bladder. ***Transitional, Urinary bladder*** - The image displays multiple layers of cells, with superficial cells appearing **dome-shaped** or **umbrella-shaped**, characteristic of transitional epithelium. - This specialized epithelium is found in the **urinary system** (e.g., bladder, ureters) and allows for stretching and distension. *Pseudo stratified columnar, Respiratory system* - **Pseudostratified columnar epithelium** appears to have multiple layers of nuclei but all cells contact the basement membrane, and it typically contains **cilia** and **goblet cells** in the respiratory tract. - The cells in the image lack the characteristic cilia and clear goblet cells, and the superficial umbrella cells are not consistent with respiratory epithelium. *Cuboidal epithelium, Gastrointestinal system* - **Cuboidal epithelium** consists of cube-shaped cells and is typically found in glands or ducts, or lining small tubules, which is not what is shown in the image. - The gastrointestinal system primarily features **simple columnar epithelium** for absorption and secretion, not cuboidal epithelium in this multi-layered arrangement. *Ciliated columnar, Female genital system* - **Ciliated columnar epithelium** would show tall, column-shaped cells with cilia on their apical surface, often found in parts of the female reproductive tract like Fallopian tubes. - The cells in the image are not distinctly columnar, nor do they exhibit visible cilia, and the multi-layered arrangement does not match typical ciliated columnar epithelium.

Q: Name the structure marked as $X$ :

Pacinian Corpuscle in dermis. ***Pacinian Corpuscle in dermis*** - The image displays a **lamellated, onion-like structure** indicative of a Pacinian corpuscle, which is a type of **mechanoreceptor**. - These corpuscles are found in the **dermis** and subcutaneous tissue, specializing in sensing **deep pressure and vibration**. *Ruffini nerve endings in Epidermis* - **Ruffini nerve endings** are typically found in the **dermis**, not the epidermis, and are responsible for sensing **stretch and sustained pressure**. - Their histological appearance is **spindle-shaped** and less complex than the lamellar structure shown. *Purkinje cells in cerebellum* - **Purkinje cells** are large, flask-shaped neurons with extensive dendritic trees, found in the **cerebellar cortex**. - They are clearly distinct from the encapsulated sensory receptor shown in the image. *Osteoclasts in bone marrow* - **Osteoclasts** are large, multi-nucleated cells responsible for **bone resorption**, found on bone surfaces or within bone marrow. - Their histological appearance is characteristic of a macrophage lineage, not an encapsulated nerve ending.

Q: Identify the type of epithelium shown in the image:

Pseudostratified columnar. ***Pseudostratified columnar*** - This epithelium appears to have multiple layers of nuclei at different levels, which is characteristic of **pseudostratified epithelium**, but all cells are in contact with the basement membrane. - The cells are taller than they are wide, indicating they are **columnar**, and the presence of cilia on the apical surface suggests it is a ciliated variety, commonly found in the **respiratory tract**. - The key identifying feature is nuclei at varying heights creating a false appearance of stratification. *Cuboidal epithelium* - **Cuboidal cells** are typically cube-shaped, with their height and width being roughly equal, and they usually have a single, centrally located nucleus. - The cells in the image are clearly taller than they are wide and exhibit nuclei at varying heights, ruling out a cuboidal morphology. *Simple columnar epithelium* - **Simple columnar epithelium** has a single layer of columnar cells with nuclei aligned at the same level, typically in the basal region. - The image shows nuclei at **different levels**, creating the characteristic pseudostratified appearance, which distinguishes it from true simple columnar epithelium. - While both are columnar, the nuclear arrangement is the key differentiating feature. *Transitional* - **Transitional epithelium** is characterized by its ability to stretch and flatten, a feature of the urinary tract, and typically has umbrella cells on its surface. - The cells in the image do not show the characteristic morphology of transitional epithelium, nor the distinct umbrella cells.

Question 1

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

Accepted Answer

A

Answer

B

Answer

C

Answer

D

Question 2

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 3

The image shows histological section of cerebellum. Identify the structures labeled in the image:

Accepted Answer

Three layers of cerebellar cortex

Answer

Deep nuclei of cerebellum

Answer

Layers of cerebral cortex

Answer

Basal ganglia

Question 4

Identify the cell in the given histological image which does not migrate from the base of the crypt to ends of villi: (Recent NEET Pattern 2016-17)

Accepted Answer

Paneth cell

Answer

Goblet cell

Answer

Oxyntic cell

Answer

Chief cell

Question 5

Which of the following is Paneth cell?

Accepted Answer

4

Answer

1

Answer

2

Answer

3

Question 6

Name the epithelium shown in the picture:

Accepted Answer

Pseudostratified columnar epithelium

Answer

Simple cuboidal epithelium

Answer

Transitional epithelium

Answer

Simple ciliated columnar epithelium

Question 7

Identify the epithelium shown in the picture.

Accepted Answer

Transitional, Urinary bladder

Answer

Pseudo stratified columnar, Respiratory system

Answer

Cuboidal epithelium, Gastrointestinal system

Answer

Ciliated columnar, Female genital system

Question 8

Name the epithelium, and the area where it is found:

Accepted Answer

Pseudostratified columnar, Respiratory system

Answer

Cuboidal epithelium, Gastrointestinal system

Answer

Ciliated columnar, Female genital system

Answer

Transitional, Urinary bladder

Question 9

Name the structure marked as $X$ :

Accepted Answer

Pacinian Corpuscle in dermis

Answer

Ruffini nerve endings in Epidermis

Answer

Purkinje cells in cerebellum

Answer

Osteoclasts in bone marrow

Question 10

Identify the type of epithelium shown in the image:

Accepted Answer

Pseudostratified columnar

Answer

Cuboidal epithelium

Answer

Simple columnar epithelium

Answer

Transitional

Histology — MCQs

Histology — MCQs

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