Histology Practice Questions

Q: Where does urine collect in case of an extraperitoneal rupture of the bladder?

Above the urogenital diaphragm. ### Explanation **1. Why "Above the urogenital diaphragm" is correct:** The urinary bladder is located extraperitoneally in the **true pelvis**, resting superior to the urogenital diaphragm (triangular ligament). When an extraperitoneal rupture occurs—most commonly associated with **pelvic fractures** [1]—the integrity of the bladder wall is breached below the peritoneal reflection. Consequently, urine extravasates into the **prevesical space (Space of Retzius)** and the surrounding pelvic extraperitoneal connective tissue. Since the urogenital diaphragm forms the floor of the pelvic cavity, the extravasated urine remains confined **above** this diaphragm within the pelvic fascia [3]. **2. Why the other options are incorrect:** * **Options A & B (Perineal space / Below the urogenital diaphragm):** These locations are involved in **extraperitoneal rupture of the urethra**, not the bladder [2]. Specifically, a rupture of the bulbous urethra (below the urogenital diaphragm) leads to urine collection in the superficial perineal pouch. This urine can then track into the scrotum and anterior abdominal wall (deep to Scarpa’s fascia) but is anatomically separated from the bladder's pelvic compartment by the urogenital diaphragm. **3. Clinical Pearls for NEET-PG:** * **Intraperitoneal Rupture:** Occurs at the **bladder dome** (the only part covered by peritoneum), usually due to blunt trauma to a full bladder. * **Extraperitoneal Rupture:** Most common type; usually associated with **pubic arch fractures** [1]. * **Classic Presentation:** Gross hematuria, suprapubic pain, and inability to void [1]. * **Investigation of Choice:** Retrograde Cystography (shows "flame-shaped" extravasation in extraperitoneal cases) [1].

Q: Nissl's granules contain which of the following?

Ribosomes. Explanation: **Nissl’s granules** (also known as Nissl bodies) are large, granular structures found in the cytoplasm of neurons. They are composed of **Rough Endoplasmic Reticulum (RER)** and free **ribosomes** [1]. Their primary function is protein synthesis, which is essential for maintaining the high metabolic activity of neurons and producing neurotransmitters [1, 3]. * **Why Ribosomes (Option D) is correct:** Nissl bodies are essentially stacks of RER. Since ribosomes are the protein-manufacturing machinery attached to the RER (and also present freely), they are the defining component of these granules [1]. They stain intensely with basic dyes (basophilic) like methylene blue or cresyl violet due to the high RNA content. **Analysis of Incorrect Options:** * **Mitochondria (A):** While neurons are rich in mitochondria to meet energy demands, they are distinct organelles and are not part of the Nissl substance. * **Golgi bodies (B):** The Golgi apparatus is involved in packaging proteins but is structurally separate from the Nissl bodies. * **Smooth Endoplasmic Reticulum (C):** SER is involved in lipid synthesis and calcium storage. Nissl granules are specifically composed of *Rough* ER, which is studded with ribosomes [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Distribution:** Nissl granules are found in the **cell body (soma)** and **dendrites**, but they are notably **absent in the Axon and Axon Hillock** [2]. * **Chromatolysis:** When an axon is injured, Nissl granules disperse and disappear from the cell body to initiate repair [3]. This histological change is called chromatolysis [3]. * **Staining:** They are best visualized using **Nissl staining** (e.g., Cresyl Violet), which targets the acidic RNA in the ribosomes.

Q: Kupffer cells in the liver are responsible for which function?

Phagocytic functions. ### Explanation **Correct Answer: D. Phagocytic functions** **1. Why Phagocytic functions is correct:** Kupffer cells are specialized **macrophages** located within the sinusoids of the liver. They are part of the **Mononuclear Phagocyte System (MPS)**. Their primary role is to act as a filter for blood entering the liver from the portal circulation. They engulf and digest cellular debris, aged red blood cells (recycling iron), and systemic pathogens (bacteria and endotoxins). By doing so, they provide the first line of immune defense in the liver [3]. **2. Why other options are incorrect:** * **A. Lytic functions:** While Kupffer cells contain lysosomes for intracellular digestion, "lytic function" usually refers to the secretion of enzymes to break down extracellular structures or the action of Natural Killer (NK) cells (Pit cells in the liver). * **B. Excretory functions:** Excretion in the liver is primarily the role of **Hepatocytes**, which produce bile and transport waste products into the biliary canaliculi [4]. * **C. Absorptive functions:** Absorption of nutrients and vitamins is the primary role of the intestinal epithelium and, to an extent, hepatocytes and **Ito cells** (which store Vitamin A) [1]. **3. High-Yield Facts for NEET-PG:** * **Origin:** Like all macrophages, Kupffer cells are derived from circulating **monocytes** [3]. * **Location:** They are found attached to the endothelial lining of the **hepatic sinusoids** [2]. * **Pit Cells:** These are the liver-specific **Natural Killer (NK) cells** found in the sinusoids. * **Ito Cells (Stellate Cells):** Located in the **Space of Disse**; they store Vitamin A and are responsible for liver fibrosis (collagen production) in cirrhosis [1]. * **Space of Disse:** The perisinusoidal space between the endothelial cells and hepatocytes where nutrient exchange occurs [1].

Q: What type of epithelium lines the mucosa of the gallbladder?

Columnar. The gallbladder is lined by a **Simple Columnar Epithelium**. These cells are characterized by their tall, rectangular shape and are specialized for the absorption of water and electrolytes, a process essential for concentrating bile stored within the gallbladder. A distinguishing feature of these cells is the presence of numerous **microvilli** (striated border) on their apical surface, which significantly increases the surface area for absorption. **Analysis of Options:** * **A. Cuboidal:** Simple cuboidal epithelium is typically found in areas of secretion or small conduits, such as the thyroid follicles or renal tubules, but not in the gallbladder. * **B. Transitional (Urothelium):** This specialized stratified epithelium is unique to the urinary tract (e.g., bladder, ureters), allowing for distension. * **C. Columnar (Correct):** The tall cells are optimized for the gallbladder's primary function of bile concentration. * **D. Squamous:** Simple squamous epithelium is found where rapid diffusion is required (e.g., alveoli, endothelium), while stratified squamous lines protective surfaces (e.g., esophagus). **High-Yield NEET-PG Pearls:** 1. **Absence of Muscularis Mucosae:** Unlike most of the GI tract, the gallbladder wall lacks a muscularis mucosae and a true submucosa [1]. 2. **Rokitansky-Aschoff Sinuses:** These are deep invaginations of the mucosa into the muscular layer, often associated with chronic cholecystitis. 3. **Luschka’s Ducts:** Small bile ducts found in the connective tissue between the liver and gallbladder; they are a common cause of bile leaks post-cholecystectomy. 4. **No Goblet Cells:** Under normal physiological conditions, the gallbladder mucosa does **not** contain goblet cells or glands (except in the neck region). Presence of goblet cells indicates intestinal metaplasia.

Q: What is the primary function of hepatic stellate cells?

Vitamin A storage. **Explanation:** **Hepatic Stellate Cells (HSCs)**, also known as **Ito cells** or lipocytes, are specialized perisinusoidal cells located in the **Space of Disse** (the area between hepatocytes and sinusoidal endothelial cells) [1]. 1. **Why Option A is Correct:** The primary physiological function of hepatic stellate cells is the **storage of Vitamin A (retinoids)** in the form of cytoplasmic lipid droplets. In a healthy liver, these cells remain in a "quiescent state" and serve as the body's largest reservoir for Vitamin A. 2. **Why Other Options are Incorrect:** * **Option B:** Sinusoids are formed by **fenestrated endothelial cells**, which lack a basement membrane to allow for rapid exchange of macromolecules [1]. * **Option C:** While stellate cells have some contractile properties that can influence sinusoidal tone, they do not primarily "increase" perfusion; rather, their activation often leads to increased resistance [1]. * **Option D:** Phagocytosis is the primary function of **Kupffer cells**, which are specialized macrophages located within the lumen of the hepatic sinusoids [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Pathology (Fibrosis):** In response to chronic liver injury (e.g., alcohol, hepatitis), quiescent stellate cells undergo **activation** into **myofibroblasts**. These activated cells lose their Vitamin A droplets and secrete excessive **Type I and Type III collagen**, making them the central players in **liver fibrosis and cirrhosis**. * **Marker:** Desmin is a common immunohistochemical marker used to identify these cells. * **Location:** Always remember they reside in the **Space of Disse** [1].

Q: Which type of collagen is distributed in rhabdomyosarcoma cells?

Type XIX. **Explanation:** The correct answer is **Type XIX Collagen**. **1. Why Type XIX is Correct:** Type XIX collagen is a member of the **FACIT** (Fibril-Associated Collagens with Interrupted Triple Helices) family. It is primarily expressed during the embryonic development of skeletal muscle (myogenesis). In adults, its expression is highly restricted; however, it is significantly re-expressed in **rhabdomyosarcoma cells** (a malignant tumor of skeletal muscle origin). It serves as a specific biomarker for muscle differentiation in these neoplastic cells and plays a role in the organization of the muscle basement membrane. **2. Analysis of Incorrect Options:** * **Type V:** This is a regulatory fibrillar collagen found in tissues containing Type I collagen (like skin and bone). It is crucial for regulating the diameter of Type I collagen fibrils but is not a specific marker for rhabdomyosarcoma. * **Type XII:** Another member of the FACIT family, Type XII is typically found in tissues subjected to high mechanical stress, such as tendons and ligaments, where it interacts with Type I collagen. * **Type XXIV:** This is an unconventional fibrillar collagen primarily expressed in developing bone (osteoblasts) and the cornea. It is not associated with myogenic tumors. **3. High-Yield Clinical Pearls for NEET-PG:** * **Rhabdomyosarcoma Marker:** While Type XIX collagen is a histological marker, the most common immunohistochemical (IHC) markers used clinically are **Desmin, Myogenin, and MyoD1** [1]. * **FACIT Collagens:** Remember Types IX, XII, XIV, XVI, and XIX belong to this group. * **Collagen Mnemonic:** * Type I: Bone (One) * Type II: Cartilage (Car-two-lage) * Type III: Reticulin (Blood vessels/Granulation tissue) * Type IV: Basement Membrane (Under the floor)

Q: Which of the following statements about Peyronie's disease is FALSE?

The condition primarily affects adolescent males.. ### Explanation **Peyronie’s Disease** is a localized connective tissue disorder characterized by the formation of a fibrous, non-compliant plaque in the **tunica albuginea** of the penis. **1. Why Option B is the Correct Answer (False Statement):** Peyronie’s disease is **not** a condition of adolescence. It primarily affects middle-aged and older men, typically between the ages of **45 and 60 years**. The pathophysiology involves repetitive microvascular injury during intercourse, leading to an abnormal wound-healing response that is rarely seen in the adolescent population. **2. Analysis of Other Options:** * **Option A:** While many cases require intervention, spontaneous resolution or significant improvement of symptoms (especially pain) occurs in approximately **10% to 50%** of patients during the initial "active" inflammatory phase. * **Option C:** There is a known genetic and systemic association between Peyronie’s disease and other fibromatoses. Approximately **20%** of patients also have **Dupuytren’s contracture** (palmar fascia thickening), and less commonly, Ledderhose disease (plantar fascia). * **Option D:** The clinical presentation typically includes **painful erections** (during the acute phase), penile curvature (chordee), and palpable firm plaques, which can lead to erectile dysfunction. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** The plaque consists of dense collagen (Type I and III) and decreased elastin fibers within the tunica albuginea. * **Site:** Most commonly affects the **dorsal aspect** of the penis, leading to upward curvature. * **Treatment:** Medical management includes Vitamin E, Potaba, or intralesional injections (Collagenase *Clostridium histolyticum*). Surgery (Nesbit procedure) is reserved for stable, severe deformities.

Question 1

Where does urine collect in case of an extraperitoneal rupture of the bladder?

Accepted Answer

Above the urogenital diaphragm

Answer

Perineal space

Answer

Below the urogenital diaphragm

Answer

None of the above

Question 2

Nissl's granules contain which of the following?

Accepted Answer

Ribosomes

Answer

Mitochondria

Answer

Golgi bodies

Answer

Smooth Endoplasmic reticulum

Question 3

Kupffer cells in the liver are responsible for which function?

Accepted Answer

Phagocytic functions

Answer

Lytic functions

Answer

Excretory functions

Answer

Absorptive functions

Question 4

What type of epithelium lines the mucosa of the gallbladder?

Accepted Answer

Columnar

Answer

Cuboidal

Answer

Transitional

Answer

Squamous

Question 5

What is the primary function of hepatic stellate cells?

Accepted Answer

Vitamin A storage

Answer

Formation of sinusoids

Answer

Increase blood perfusion

Answer

Phagocytosis

Question 6

Which type of collagen is distributed in rhabdomyosarcoma cells?

Accepted Answer

Type XIX

Answer

Type V

Answer

Type XII

Answer

Type XXIV

Question 7

Which of the following statements about healthy, intact capillaries is true?

Accepted Answer

They inhibit clot formation.

Answer

They control blood pressure.

Answer

They are lined by a simple columnar epithelium.

Answer

They have a smooth muscle coat.

Question 8

Which muscle originates from bone and the interosseous membrane?

Accepted Answer

Tibialis anterior

Answer

Peroneus longus

Answer

Peroneus brevis

Answer

Tibialis posterior

Question 9

Which of the following statements concerning skin melanocytes is true?

Accepted Answer

They synthesize a pigment that protects against damage caused by UV radiation.

Answer

They are located only in the dermis.

Answer

They produce keratohyalin granules.

Answer

They may give rise to basal cell carcinoma.

Question 10

Which of the following statements about Peyronie's disease is FALSE?

Accepted Answer

The condition primarily affects adolescent males.

Answer

Spontaneous regression occurs in approximately 50% of cases.

Answer

Peyronie's disease can be associated with Dupuytren's contracture of the hand.

Answer

Patients may present with complaints of painful erections.

Histology — MCQs

Histology — MCQs

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