Histology Practice Questions

Q: Fibromuscular stroma is present in which of the following organs?

Prostate. The **prostate gland** is unique because it is not purely glandular; it is a **fibromuscular organ**. Its stroma consists of a dense mixture of smooth muscle fibers and collagenous connective tissue. ### Why Prostate is Correct: The prostate is composed of approximately **70% glandular tissue** and **30% fibromuscular stroma**. This stroma is continuous with the capsule and contains smooth muscle fibers that contract during ejaculation to squeeze prostatic secretions into the prostatic urethra. A key anatomical landmark is the **Anterior Fibromuscular Stroma (AFMS)**, which forms the anterior surface of the prostate and is devoid of glandular elements. ### Why Other Options are Incorrect: * **Testis:** The structural framework consists of the *tunica albuginea* (dense connective tissue), but the parenchyma is dominated by seminiferous tubules, not a specialized fibromuscular stroma. * **Liver:** The liver is covered by *Glisson’s capsule*. Its internal framework consists of a delicate reticular fiber network (Type III collagen) to support hepatocytes, lacking a significant smooth muscle component. * **Urinary Bladder:** While the bladder wall contains thick smooth muscle (the *detrusor muscle*), it is classified as a hollow muscular organ rather than a gland with a fibromuscular stroma [1]. ### High-Yield Clinical Pearls for NEET-PG: * **BPH (Benign Prostatic Hyperplasia):** Primarily involves the **Transition Zone**. The stromal component (smooth muscle) is the target for **Alpha-1 blockers** (e.g., Tamsulosin), which relax the stroma to improve urine flow. * **Prostate Cancer:** Most commonly arises in the **Peripheral Zone**. * **Histology Tip:** On an H&E stain, the prostatic stroma appears characteristically pink (eosinophilic) due to the high density of smooth muscle.

Q: C cells are present in which gland?

Thyroid gland. C cells, also known as **Parafollicular cells**, are neuroendocrine cells located within the connective tissue between the thyroid follicles or embedded in the follicular lining. Their primary function is to secrete **Calcitonin**, a hormone that lowers blood calcium levels by inhibiting osteoclast activity and increasing renal calcium excretion [1]. **2. Why Other Options are Incorrect:** * **Parathyroid Gland:** This gland contains **Chief cells** (which secrete Parathyroid Hormone/PTH) and **Oxyphil cells** [2]. PTH is the functional antagonist to Calcitonin. * **Pituitary Gland:** The anterior lobe contains acidophils (Somatotropes, Lactotropes) and basophils (Corticotropes, Thyrotropes, Gonadotropes), while the posterior lobe contains pituicytes and axonal terminals. * **Thymus:** This lymphoid organ contains T-lymphocytes (thymocytes) and **Hassall’s corpuscles** (epithelial reticular cells), but no C cells. **3. High-Yield Clinical Pearls for NEET-PG:** * **Embryology:** C cells are derived from the **Ultimobranchial body** (ventral wing of the 4th/5th pharyngeal pouch), which originates from the **Neural Crest**. * **Tumor Marker:** C cells are the cells of origin for **Medullary Carcinoma of the Thyroid (MTC)**. Serum Calcitonin levels are used as a specific tumor marker for diagnosis and follow-up [3]. * **MEN Syndrome:** Medullary thyroid carcinoma is a key component of **MEN 2A and 2B** syndromes [3]. * **Staining:** C cells can be identified using immunohistochemistry for **Chromogranin** or **Calcitonin**.

Q: Which of the following statements are true about Nissl granules?

Present in axon. Nissl granules (or Nissl bodies) are large granular structures found in the cytoplasm of neurons. They are composed of **Rough Endoplasmic Reticulum (RER)** and free ribosomes, making them the primary site of **protein synthesis** within the neuron [1]. **Analysis of Options:** * **Correct Answer (B):** This question follows a common pattern in medical exams where the "correct" answer is actually a **negative fact** (identifying the exception). Nissl granules are **absent in the axon** and the **axon hillock** [2]. Their absence in the axon is a defining histological feature used to distinguish axons from dendrites under a microscope. * **Option A:** Nissl granules are involved in translation (protein synthesis), not transcription (RNA synthesis). RNA synthesis occurs in the nucleus/nucleolus. * **Option C:** Nissl granules are present in the cell body (soma) and extend into the proximal portions of **dendrites**, but never into the axon [2]. * **Option D:** This is a true physiological function of Nissl granules. However, in the context of "identifying" Nissl granules in neuroanatomy exams, the most high-yield anatomical fact is their absence in the axon. **NEET-PG High-Yield Pearls:** 1. **Tigroid Appearance:** Nissl substance gives the cytoplasm a spotted or "tigroid" appearance under basic dyes (like Cresyl violet). 2. **Chromatolysis:** When an axon is injured, Nissl granules disperse and disappear from the cell body to prioritize repair. This process is called chromatolysis. 3. **Axon Hillock:** This is the cone-shaped area of the cell body that leads into the axon; it is notably devoid of Nissl granules [2].

Q: Elastic cartilage is found in which of the following locations?

Auditory tube. **Explanation:** Cartilage is classified into three types based on the composition of its intercellular matrix: Hyaline, Elastic, and Fibrocartilage. **Elastic cartilage** is characterized by a dense network of branching elastic fibers, providing both flexibility and structural integrity. **Why the Auditory Tube is Correct:** The **Auditory (Eustachian) tube** (specifically its cartilaginous part) consists of elastic cartilage. This allows the tube to remain flexible enough to open and close during swallowing or yawning to equalize middle ear pressure. Other classic locations for elastic cartilage include the **Auricle (Pinna)**, **External Auditory Meatus**, and the **Epiglottis** (Mnemonic: The "3 Es" – Eustachian tube, Epiglottis, External ear). **Analysis of Incorrect Options:** * **Nasal Septum (B):** Composed of **Hyaline cartilage**. This is the most common type of cartilage, providing a smooth surface and structural support. * **Auricular Cartilage (C):** While the Auricle *is* elastic cartilage, in the context of standardized NEET-PG questions where multiple options might seem correct, the **Auditory tube** is often the specific focus of histological classification. *Note: If this were a "Multiple Correct" format, both A and C would be right; however, in single-best-answer formats, the Auditory tube is a high-yield anatomical landmark.* * **Costal Cartilage (D):** Composed of **Hyaline cartilage**. These connect the ribs to the sternum and are prone to calcification with age. **High-Yield Clinical Pearls for NEET-PG:** * **Calcification:** Hyaline cartilage commonly calcifies with age, whereas **Elastic cartilage never calcifies**. * **Articular Cartilage:** A subtype of hyaline cartilage found in joints; it lacks a perichondrium. * **Fibrocartilage:** Found in the intervertebral discs, pubic symphysis, and TMJ; it is the strongest type and lacks a perichondrium.

Q: Cuboidal epithelium lines which of the following structures?

Distal convoluted tubule. **Explanation:** The renal tubule is lined by different types of epithelia, specifically adapted to the physiological functions of each segment. [1] **Correct Option: (A) Distal Convoluted Tubule (DCT)** The DCT is lined by **simple cuboidal epithelium**. Unlike the proximal tubule, the cells here lack a prominent brush border (microvilli), giving the lumen a cleaner, more distinct appearance under light microscopy. This structure supports its role in the selective secretion and reabsorption of ions under hormonal influence (e.g., Aldosterone). **Analysis of Incorrect Options:** * **(B) Descending Loop of Henle:** The thin descending limb is lined by **simple squamous epithelium**, which is highly permeable to water but impermeable to solutes. * **(C) Proximal Convoluted Tubule (PCT):** While the PCT is also cuboidal, it is specifically characterized as **simple cuboidal epithelium with a prominent brush border** (microvilli). [1] This increases the surface area for the reabsorption of 65-70% of the glomerular filtrate. In exams, if "Cuboidal" and "Brush-bordered Cuboidal" are both options, the latter is specific to the PCT. * **(D) Ascending Loop of Henle:** This segment is divided into two parts: the thin ascending limb (simple squamous) and the **thick ascending limb (simple cuboidal)**. However, in standard medical nomenclature and competitive exams, the DCT is the classic textbook example for simple cuboidal epithelium in the nephron. **High-Yield Clinical Pearls for NEET-PG:** * **Simple Squamous:** Lines the Bowman’s capsule (parietal layer), thin Loop of Henle, and Alveoli (Type I pneumocytes). * **Simple Columnar:** Lines the Stomach, Intestines, and Gallbladder. * **Ciliated Columnar:** Found in the Fallopian tubes and Bronchioles. * **Transitional Epithelium (Urothelium):** Lines the Renal pelvis, Ureter, and Urinary bladder.

Q: Where are Peyer's patches located in the gastrointestinal tract?

Ileum. Peyer’s patches are organized lymphoid follicles located in the lamina propria and submucosa of the small intestine. They are a critical component of the Gut-Associated Lymphoid Tissue (GALT). [1] 1. Why Ileum is Correct: While lymphoid tissue is found throughout the GI tract, Peyer’s patches are a characteristic histological hallmark of the Ileum. They are most numerous and largest in the distal ileum. They play a vital role in immune surveillance by sampling intestinal antigens via specialized M-cells (Microfold cells). Approximately 40% of the lymphoid cells in the lamina propria are B cells, which are primarily derived from precursors in Peyer's patches [2]. 2. Why Other Options are Incorrect: * Duodenum: Characterized by Brunner’s glands in the submucosa, which secrete alkaline mucus to neutralize gastric acid. * Jejunum: Characterized by tall, leaf-like villi and prominent Plicae Circulares (Valves of Kerckring), which are most developed here for maximum absorption. * Colon: Contains abundant goblet cells and solitary lymphoid nodules, but lacks the organized, aggregated Peyer’s patches seen in the ileum. High-Yield Clinical Pearls for NEET-PG: * Location: They are always situated on the antimesenteric border of the ileum. * Clinical Significance: In Typhoid fever (Enteric fever), Salmonella typhi targets Peyer’s patches, leading to hyperplasia, followed by necrosis and longitudinal ulceration. These ulcers can lead to intestinal perforation. * Intussusception: Hypertrophy of Peyer’s patches (often following a viral infection) can act as a lead point, causing the bowel to telescope into itself. * Histology: They are located primarily in the submucosa but can extend into the lamina propria, displacing the overlying intestinal crypts.

Q: Oxyntic cells are found in which part of the digestive tract?

Stomach. **Explanation:** **Oxyntic cells**, also known as **Parietal cells**, are specialized epithelial cells located primarily in the **stomach**. They are found within the gastric glands of the fundus and body of the stomach. Their primary physiological role is the secretion of **Hydrochloric acid (HCl)**, which maintains the acidic pH necessary for protein digestion, and **Intrinsic Factor (IF)**, which is essential for the absorption of Vitamin B12 in the terminal ileum. **Analysis of Options:** * **Stomach (Correct):** The oxyntic (parietal) cells are a hallmark of the gastric mucosa. They contain an extensive tubulovesicular system and canaliculi to facilitate the active transport of H+ ions via the H+/K+ ATPase pump. * **Small Intestine:** This region contains Enterocytes, Goblet cells, and Paneth cells (in the Crypts of Lieberkühn), but lacks acid-secreting oxyntic cells. * **Large Intestine:** The mucosa here is primarily involved in water absorption and mucus secretion (Goblet cells); it does not possess oxyntic cells. * **Esophagus:** The esophagus is lined by non-keratinized stratified squamous epithelium designed for protection against mechanical friction, not for secretion of acid or enzymes. **High-Yield Clinical Pearls for NEET-PG:** 1. **Pernicious Anemia:** Autoimmune destruction of oxyntic cells leads to a deficiency of Intrinsic Factor, resulting in Vitamin B12 malabsorption and megaloblastic anemia. 2. **Achlorhydria:** The absence of HCl secretion due to oxyntic cell dysfunction. 3. **Stimulants of Secretion:** Oxyntic cells are stimulated by **Gastrin** (via CCK2 receptors), **Acetylcholine** (via M3 receptors), and **Histamine** (via H2 receptors). 4. **Omeprazole:** This Proton Pump Inhibitor (PPI) works by irreversibly inhibiting the **H+/K+ ATPase pump** located on the apical membrane of oxyntic cells.

Q: Which statement about articular cartilage is true?

It has no nerve supply.. **Explanation:** Articular cartilage is a specialized type of **hyaline cartilage** that covers the weight-bearing surfaces of bones within synovial joints [1]. Its primary function is to provide a smooth, lubricated surface for low-friction articulation and to facilitate the transmission of loads to the underlying bone [1]. **1. Why the correct answer is right:** Articular cartilage is unique because it is **aneural, avascular, and alymphatic** [1]. It lacks a nerve supply, which is why initial stages of cartilage degeneration (like early osteoarthritis) are often painless. Pain in joint diseases typically arises only when the underlying subchondral bone (which is highly innervated) or the surrounding synovium is affected [2]. **2. Why the incorrect options are wrong:** * **Option A:** It is **avascular**. Chondrocytes receive their nutrition via diffusion from the synovial fluid and the subchondral bone [1]. * **Option B:** Unlike most hyaline cartilage, articular cartilage **lacks a perichondrium**. The absence of perichondrium allows for a smooth friction-free surface but also results in a very limited capacity for regeneration and repair. * **Option D:** It is **hyaline cartilage**, not fibrocartilage. Fibrocartilage (found in intervertebral discs and symphysis pubis) contains thick bundles of Type I collagen, whereas articular cartilage primarily contains **Type II collagen** [1]. **High-Yield NEET-PG Pearls:** * **Composition:** 70-80% water, Type II collagen, and Proteoglycans (Aggrecan) [1]. * **Growth:** It grows via interstitial and appositional growth (though appositional growth is absent in articular cartilage due to lack of perichondrium). * **Calcification:** It is the only cartilage that does not readily calcify except in the "tidemark" zone bordering subchondral bone.

Q: The Space of Disse contains all except:

Kupffer's cell. ### Explanation The **Space of Disse** (perisinusoidal space) is a critical anatomical gap located between the fenestrated endothelium of the hepatic sinusoids and the surface of the hepatocytes [1]. **Why Option C is the correct answer:** **Kupffer cells** are specialized fixed macrophages of the liver. They are located **intraluminally**, attached to the luminal surface of the sinusoidal endothelial cells. Because they reside within the sinusoid itself to phagocytose pathogens from the blood, they are not found within the Space of Disse. **Analysis of Incorrect Options:** * **Option A (Microvilli):** The basal surface of hepatocytes is covered with numerous microvilli that project into the Space of Disse [1]. This significantly increases the surface area for the exchange of metabolites between the blood and hepatocytes [1]. * **Option B (Blood plasma):** The sinusoidal endothelium is highly fenestrated and lacks a continuous basement membrane [1]. This allows the liquid portion of the blood (plasma) to filter freely into the Space of Disse, bringing it into direct contact with hepatocytes [1], [2]. **High-Yield Facts for NEET-PG:** 1. **Ito Cells (Stellate Cells):** These are the most important cells located *within* the Space of Disse. They store **Vitamin A** in lipid droplets. 2. **Clinical Correlation:** In chronic liver injury, Ito cells transform into myofibroblasts, producing excess collagen (Type I and III), which leads to **liver fibrosis** and cirrhosis. 3. **Lymph Formation:** The Space of Disse is the primary site for the formation of hepatic lymph; it drains into the **Space of Mall** before entering the lymphatic vessels.

Question 1

Fibromuscular stroma is present in which of the following organs?

Accepted Answer

Prostate

Answer

Testis

Answer

Liver

Answer

Urinary bladder

Question 2

C cells are present in which gland?

Accepted Answer

Thyroid gland

Answer

Parathyroid gland

Answer

Pituitary gland

Answer

Thymus

Question 3

Which of the following statements are true about Nissl granules?

Accepted Answer

Present in axon

Answer

Involves in RNA synthesis

Answer

Present in dendrites

Answer

Involves in protein synthesis

Question 4

Elastic cartilage is found in which of the following locations?

Accepted Answer

Auditory tube

Answer

Nasal septum

Answer

Auricular cartilage

Answer

Costal cartilage

Question 5

Cuboidal epithelium lines which of the following structures?

Accepted Answer

Distal convoluted tubule

Answer

Descending loop of Henle

Answer

Proximal convoluted tubule

Answer

Ascending loop of Henle

Question 6

Where are Peyer's patches located in the gastrointestinal tract?

Accepted Answer

Ileum

Answer

Duodenum

Answer

Jejunum

Answer

Colon

Question 7

Oxyntic cells are found in which part of the digestive tract?

Accepted Answer

Stomach

Answer

Small intestine

Answer

Large intestine

Answer

Esophagus

Question 8

What is the primary protein responsible for the tensile strength of tendons?

Accepted Answer

Collagen

Answer

Fibrillin

Answer

Fibronectin

Answer

Elastin

Question 9

Which statement about articular cartilage is true?

Accepted Answer

It has no nerve supply.

Answer

It is a very vascular structure.

Answer

It is surrounded by a thick perichondrium.

Answer

It is fibrocartilage.

Question 10

The Space of Disse contains all except:

Accepted Answer

Kupffer's cell

Answer

Microvilli

Answer

Blood plasma

Answer

None of the above

Histology — MCQs

Histology — MCQs

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