Histology Practice Questions

Q: The histological section shown in the image, characterized by predominantly serous acini, is best identified as which organ?

Parotid gland. ***Parotid gland*** - The parotid gland is a **purely serous** salivary gland, meaning its secretory acini consist exclusively of serous cells that secrete a watery, enzyme-rich fluid. - It is histologically distinguished by the presence of numerous **striated ducts** and **intercalated ducts** scattered throughout the serous acinar tissue, which helps differentiate it from other salivary glands or the pancreas. *Sublingual salivary gland* - This gland is classified as a **mucous-predominant** gland, meaning the majority of its acini are composed of mucous cells, not serous cells. - It typically features **mucous acini** often capped by serous demilunes, appearing structurally distinct from the purely serous morphology of the parotid gland. *Pancreas* - While the pancreas contains purely serous acini, it is distinguished from the parotid gland by the presence of **Islets of Langerhans** (endocrine tissue) and the absolute absence of striated ducts. - The acini in the pancreas typically show **centroacinar cells**, a feature uniquely characteristic of the pancreatic exocrine system and absent in salivary glands. *Liver* - The liver is organized into **hepatic lobules** (hexagonal structures) rather than acinar glandular units. - Histologically, it consists primarily of **hepatocytes** arranged in plates separated by sinusoids, not secretory acini like those found in salivary glands or the pancreas.

Q: Match each of the following gastrointestinal organs with its distinctive histological feature: Organ Histological Feature 1. Ileum a. Taenia coli 2. Transverse colon b. Villi 3. Esophagus c. Peyer's patches 4. Duodenum d. Non-keratinized stratified squamous epithelium

1-c, 2-a, 3-d, 4-b. ***1-c, 2-a, 3-d, 4-b*** - The **ileum** is histologically distinguished by the presence of **Peyer's patches**, which are large aggregates of lymphoid tissue commonly found in the lamina propria and submucosa. - The **transverse colon** features **taeniae coli**, which are three distinct longitudinal bands of smooth muscle that run along the length of the large intestine. - The **esophagus** is lined by a **non-keratinized stratified squamous epithelium**, which provides protection against mechanical abrasion from food boluses. - The **duodenum** is characterized by the presence of prominent **villi** for nutrient absorption and **Brunner's glands** in the submucosa. *1-a, 2-c, 3-d, 4-b* - Incorrect because the **ileum** contains Peyer's patches (c), not taeniae coli (a). - Incorrect because the **transverse colon** contains taeniae coli (a), not Peyer's patches (c). *1-c, 2-b, 3-a, 4-d* - Incorrect because the **transverse colon** does not possess villi (b), as villi are a characteristic feature of the small intestine for nutrient absorption. - Incorrect because the **esophagus** does not contain taeniae coli (a), as taeniae coli are restricted to the large intestine. *1-d, 2-a, 3-c, 4-b* - Incorrect because the **ileum** is not lined by non-keratinized stratified squamous epithelium (d); that is a feature of the esophagus. - Incorrect because the **esophagus** does not contain Peyer's patches (c), which are specific to the distal small bowel.

Q: What type of tissue predominantly comprises the cervix?

Mainly collagen. The cervix is the lower, cylindrical portion of the uterus, but it differs significantly from the uterine body (corpus) in its histological composition. While the body of the uterus is primarily a muscular organ (myometrium), the **cervix is predominantly a fibrous organ.** [1] **1. Why "Mainly Collagen" is Correct:** The cervical stroma is composed of approximately **85–90% dense collagenous connective tissue**, with only about 10–15% smooth muscle. This high collagen content provides the structural integrity and "firmness" required to keep the cervix closed during pregnancy, supporting the weight of the growing fetus and the amniotic sac. [1] **2. Why Other Options are Incorrect:** * **Option A (Mainly muscle fibers):** This describes the **uterine body**, where smooth muscle is essential for powerful contractions during labor [1]. In the cervix, muscle fibers are sparse and primarily located in the outer circumferential layer. * **Option C (Equal proportions):** This is histologically inaccurate. The transition from the muscular corpus to the fibrous cervix occurs at the internal os, where the muscle content drops sharply. **3. Clinical Pearls & High-Yield Facts for NEET-PG:** * **Cervical Ripening:** During labor, the enzyme **collagenase** breaks down the collagen fibers. This biochemical change (not just muscle contraction) allows the cervix to become soft, thin (effacement), and dilate [2]. * **Epithelial Transition:** The ectocervix is lined by **stratified squamous epithelium**, while the endocervix is lined by **simple columnar epithelium**. The junction between them (Squamocolumnar Junction) is the most common site for cervical cancer. * **Consistency:** On clinical examination, the non-pregnant cervix feels firm (like the **tip of the nose**), whereas, during pregnancy, it softens (Goodell’s sign) due to increased vascularity and collagen remodeling.

Q: Aggrecan is a component of which of the following?

Important component of cartilage. **Explanation:** **Aggrecan** is the most abundant **proteoglycan** found in the extracellular matrix (ECM) of **cartilage** (specifically hyaline and fibrocartilage) [1]. It consists of a core protein to which numerous glycosaminoglycan (GAG) chains—primarily **chondroitin sulfate** and **keratan sulfate**—are covalently attached. These aggrecan molecules bind to a long strand of hyaluronic acid to form massive proteoglycan aggregates [1]. Due to its high negative charge, aggrecan attracts water, providing cartilage with its essential osmotic properties and the ability to resist compressive forces (load-bearing capacity) [1]. **Analysis of Incorrect Options:** * **Option A:** Receptors on platelets are typically glycoproteins (e.g., GpIIb/IIIa or GpIb-IX-V), not large proteoglycans like aggrecan. * **Option B:** While osteoid (unmineralized bone matrix) contains proteoglycans, its primary components are Type I collagen and non-collagenous proteins like Osteocalcin and Osteopontin [2]. Aggrecan is specific to the cartilaginous matrix. * **Option C:** Leukocyte granules contain enzymes (like myeloperoxidase), histamine, or heparin (in basophils), but not aggrecan. **High-Yield Facts for NEET-PG:** * **Cartilage Composition:** Type II collagen provides tensile strength, while Aggrecan provides compressive strength [1]. * **Link Protein:** This protein stabilizes the interaction between the aggrecan core protein and hyaluronan. * **Clinical Correlation:** Degradation of aggrecan by enzymes known as **ADAMTS** (aggrecanases) is a hallmark of early **Osteoarthritis**. * **Marker:** Aggrecan is often used as a marker for chondrocyte differentiation in histology.

Question 1

The histological section shown in the image, characterized by predominantly serous acini, is
best identified as which organ?

Accepted Answer

Parotid gland

Answer

Sublingual salivary gland

Answer

Pancreas

Answer

Liver

Question 2

Match each of the following gastrointestinal organs with its distinctive histological feature:

Organ Histological Feature

1. Ileum a. Taenia coli

2. Transverse colon b. Villi

3. Esophagus c. Peyer's patches

4. Duodenum d. Non-keratinized stratified squamous
epithelium

Accepted Answer

1-c, 2-a, 3-d, 4-b

Answer

1-a, 2-c, 3-d, 4-b

Answer

1-c, 2-b, 3-a, 4-d

Answer

1-d, 2-a, 3-c, 4-b

Question 3

What type of tissue predominantly comprises the cervix?

Accepted Answer

Mainly collagen

Answer

Mainly muscle fibers

Answer

Equal proportions of muscle and collagen

Answer

None of the above

Question 4

All the following statements are true regarding the pregnant and lactating breast, EXCEPT:

Accepted Answer

There is an increase in the interlobular connective tissue

Answer

The terminal lobular units are most affected during pregnancy

Answer

Cuboidal luminal epithelial cells show vacuolization

Answer

Fat droplets occur in the cytoplasm of the epithelium

Question 5

Aggrecan is a component of which of the following?

Accepted Answer

Important component of cartilage

Answer

Receptor over platelets

Answer

A molecule present in osteoid tissue

Answer

Granules in leukocytes

Histology — MCQs

Histology — MCQs

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