Microscopic Anatomy of Epithelial Tissues — MCQs
Intercalated ducts of serous acinar glands are lined by
Which of the following protein molecules is responsible for cell-to-cell adhesion?
Lining epithelium of vagina is
Which of the following is a common pathology that increases the risk of uterine injury during abdominal hysterectomy?
Dense irregular connective tissue is found in:
A patient presents with pulmonary hemorrhage and is P-ANCA positive. What is the most likely diagnosis?
Which of the following statements about articular cartilage is true?
Prefilaggrin is found in which layer of epidermis?
Epithelial lining of the urinary bladder is?
In articular cartilage, most active chondrocytes are seen in ?
Microscopic Anatomy of Epithelial Tissues Indian Medical PG Practice Questions and MCQs
Question 1: Intercalated ducts of serous acinar glands are lined by
- A. Stratified columnar
- B. Simple Columnar
- C. Stratified squamous
- D. Simple cuboidal (Correct Answer)
Explanation: Simple cuboidal - The **intercalated ducts** of **serous acinar glands** (such as parotid and pancreas) are lined by **simple cuboidal epithelium**. - This type of epithelium is well-suited for the initial drainage of serous secretions from the acini and allows for efficient transport through the relatively short cells. - Simple cuboidal epithelium provides both structural support and functional activity for these small caliber ducts. *Stratified columnar* - **Stratified columnar epithelium** is rare and found in specific locations like parts of the **male urethra** and some large excretory ducts. - It is not characteristic of the small intercalated ducts of serous acinar glands. *Simple Columnar* - **Simple columnar epithelium** lines **striated ducts** (the larger ducts downstream from intercalated ducts) and excretory ducts of some glands. - While found in the ductal system, it is not the epithelium of the **intercalated ducts** specifically, which are the smallest and most proximal ducts. *Stratified squamous* - **Stratified squamous epithelium** is primarily designed for protection against abrasion, found in areas like the **skin** and **esophagus**. - It is entirely unsuitable for the secretory drainage functions of glandular ducts.
Question 2: Which of the following protein molecules is responsible for cell-to-cell adhesion?
- A. Laminin
- B. Fibronectin
- C. Collagen
- D. Cadherin (Correct Answer)
Explanation: ***Cadherin*** - **Cadherins** are transmembrane proteins that mediate **direct cell-to-cell adhesion** in a calcium-dependent manner - They form **adherens junctions** and **desmosomes**, which are essential for maintaining tissue integrity - Cadherins on adjacent cells bind to each other (**homophilic binding**), creating strong cell-cell connections - Critical for **embryonic development**, tissue architecture, and **epithelial barrier function** *Fibronectin* - **Fibronectin** is an extracellular matrix glycoprotein that mediates **cell-to-ECM adhesion**, not direct cell-to-cell adhesion - It binds to **integrins** on the cell surface, facilitating cell attachment to the extracellular matrix - Important for cell migration, wound healing, and embryonic development - Does not directly connect cells to each other *Collagen* - **Collagen** is the most abundant structural protein providing **tensile strength** to connective tissues - Primarily functions as **extracellular scaffolding**, not as an adhesion molecule - Provides mechanical support but does not mediate cell-cell adhesion *Laminin* - **Laminins** are major components of the **basal lamina** (basement membrane) - Mediate **cell-to-basal lamina adhesion** through integrin receptors - Important for cell differentiation, migration, and tissue organization - Function in cell-to-ECM adhesion, not cell-to-cell adhesion
Question 3: Lining epithelium of vagina is
- A. Squamous epithelium (Correct Answer)
- B. Columnar epithelium
- C. Transitional epithelium
- D. Secretory epithelium
Explanation: Squamous epithelium * The vagina is lined by stratified squamous non-keratinized epithelium [1], providing a protective barrier against friction and pathogens. * This type of epithelium is well-suited for areas subject to significant mechanical stress, such as during intercourse and childbirth. Columnar epithelium * Columnar epithelium [2] is typically found in areas specialized for secretion and absorption, such as the gastrointestinal tract and glandular linings. * It would not offer the necessary protective qualities for the vaginal environment. Transitional epithelium * Transitional epithelium is a specialized stratified epithelium found in the urinary tract, capable of stretching and distending. * It is not found in the vagina, which requires a more robust, friction-resistant lining. Secretory epithelium * While the cervix has secretory glands, the lining of the vagina itself is not primarily secretory. * The primary role of the vaginal lining is protection, not secretion, and its cells do not typically produce a large amount of substances.
Question 4: Which of the following is a common pathology that increases the risk of uterine injury during abdominal hysterectomy?
- A. Hydrosalpinx
- B. Pelvic endometriosis (Correct Answer)
- C. Ovarian teratoma
- D. Adenomyosis
Explanation: ***Pelvic endometriosis*** - Pelvic endometriosis causes **dense adhesions, anatomical distortion, and obliteration of normal tissue planes**, making surgical dissection technically challenging during hysterectomy. - The **fibrotic adhesions** bind pelvic organs together, obscure surgical landmarks, and increase the risk of inadvertent injury to the uterus, bladder, ureters, and bowel. - Studies show that **endometriosis is a significant risk factor** for intraoperative complications, including uterine perforation and vascular injury. - The **distorted pelvic anatomy** requires careful dissection and may necessitate modifications in surgical technique. *Hydrosalpinx* - Hydrosalpinx is a **fluid-filled, dilated fallopian tube** resulting from distal tubal obstruction, typically from prior pelvic inflammatory disease. - While it may be encountered during hysterectomy, it does **not distort the uterine anatomy or create adhesions** that would increase the risk of uterine injury. - Hydrosalpinx is generally easily separated from surrounding structures. *Ovarian teratoma* - Ovarian teratoma (dermoid cyst) is a **benign germ cell tumor of the ovary** containing mature tissues from all three germ layers. - It is typically **well-encapsulated and does not cause significant pelvic adhesions** unless there has been rupture or torsion. - It does not increase the risk of uterine injury during hysterectomy. *Adenomyosis* - Adenomyosis is **endometrial tissue within the myometrium**, causing an enlarged, boggy, tender uterus. - While adenomyosis is often an **indication for hysterectomy**, it is an intrinsic uterine condition that does **not cause pelvic adhesions or anatomical distortion**. - The uterus may be more vascular and bulky, but this does not specifically increase the risk of uterine injury during standard hysterectomy technique.
Question 5: Dense irregular connective tissue is found in:
- A. Dermis (Correct Answer)
- B. Ligament
- C. Lamina propria
- D. Tendon
Explanation: ***Dermis*** - The **dermis** is primarily composed of **dense irregular connective tissue**, which provides structural strength and elasticity to the skin. [1] - This tissue consists of a rich network of **collagen fibers** arranged in various directions, along with elastic fibers, offering resistance to stress from multiple directions. [1] *Ligament* - Ligaments are examples of **dense regular connective tissue**, not irregular. - Their collagen fibers are densely packed and arranged in a **parallel fashion** to resist unidirectional stress. *Lamina propria* - The lamina propria is a layer of **loose connective tissue** underlying the epithelium of many organs. - It contains a higher proportion of **ground substance** and fewer, more loosely arranged fibers compared to dense connective tissue. *Tendon* - Tendons are also examples of **dense regular connective tissue**, connecting muscle to bone. - They are characterized by **parallel arrays of collagen fibers** adapted to withstand strong tensile forces in a single direction.
Question 6: A patient presents with pulmonary hemorrhage and is P-ANCA positive. What is the most likely diagnosis?
- A. Churg-Strauss syndrome
- B. Microscopic polyangiitis (Correct Answer)
- C. Wegener granulomatosis
- D. Polyarteritis nodosa (PAN)
Explanation: ***Microscopic polyangiitis*** - This condition is characterized by **pulmonary hemorrhage** (often manifesting as diffuse alveolar hemorrhage) and **P-ANCA positivity**, which is typically associated with antibodies against **myeloperoxidase (MPO)**. [1] - It is a **small-vessel vasculitis** that frequently affects the kidneys (glomerulonephritis) and lungs without granuloma formation. *Churg-Strauss syndrome* - While Churg-Strauss syndrome (now known as **Eosinophilic Granulomatosis with Polyangiitis**, EGPA) can be P-ANCA positive, it is typically associated with a history of **asthma**, **allergic rhinitis**, and **eosinophilia**. [1] - Pulmonary involvement often includes **infiltrates** and nodules, but diffuse alveolar hemorrhage with severe pulmonary hemorrhage is less common as the primary presentation compared to MPA. *Wegener granulomatosis* - Wegener granulomatosis (now known as **Granulomatosis with Polyangiitis**, GPA) primarily presents with **upper and lower respiratory tract granulomatous inflammation** and **glomerulonephritis**. - It is typically associated with **C-ANCA positivity** (antibodies against proteinase 3, PR3), not P-ANCA. *Polyarteritis nodosa (PAN)* - Polyarteritis nodosa is a **medium-vessel vasculitis** that typically affects the **kidneys, gastrointestinal tract, skin, and nervous system**. [1] - It is classically **ANCA-negative** and does not typically cause pulmonary hemorrhage or diffuse alveolar hemorrhage.
Question 7: Which of the following statements about articular cartilage is true?
- A. Very vascular structure
- B. Surrounded by thick perichondrium
- C. Has no nerve supply (Correct Answer)
- D. Fibrocartilage
Explanation: ***Has no nerve supply*** - Articular cartilage is **aneural**, meaning it lacks nerve endings, which is why damage to it doesn't immediately cause pain until underlying bone or surrounding tissues are affected [1]. - Its aneural nature contributes to its low metabolic activity and limited capacity for repair. *Very vascular structure* - Articular cartilage is **avascular**, meaning it lacks a direct blood supply [1]. - It receives nutrients primarily through diffusion from the synovial fluid [1]. *Surrounded by thick perichondrium* - Articular cartilage is typically **not covered by a perichondrium**, unlike most other types of cartilage. - The absence of perichondrium prevents potential ossification of the articular surface. *Fibrocartilage* - Articular cartilage is primarily composed of **hyaline cartilage**, not fibrocartilage [1]. - **Hyaline cartilage** provides a smooth, low-friction surface for joint movement and acts as a shock absorber [1].
Question 8: Prefilaggrin is found in which layer of epidermis?
- A. Stratum granulosum (Correct Answer)
- B. Stratum basale
- C. Stratum spinosum
- D. Stratum corneum
Explanation: ***Stratum granulosum*** - **Prefilaggrin** is synthesized in the **stratum granulosum** as a large, insoluble protein that is stored in keratohyalin granules [1]. - It later undergoes proteolytic cleavage to form **filaggrin**, which is crucial for keratin filament aggregation and skin barrier function in the upper layers [1]. *Stratum basale* - This layer contains **basal cells** responsible for epidermal regeneration and is where keratinocyte proliferation occurs [1]. - It does not contain prefilaggrin, as this protein is synthesized in more differentiated keratinocytes. *Stratum spinosum* - This layer is characterized by abundant **desmosomes** (spinous processes) providing structural integrity. - While keratinization begins here, **prefilaggrin synthesis** primarily occurs in the stratum granulosum. *Stratum corneum* - This outermost layer consists of flattened, dead keratinocytes filled with **keratin** and **filaggrin**, a breakdown product of prefilaggrin [1]. - **Prefilaggrin itself is not found here**; it has already been processed into filaggrin by the time cells reach this layer.
Question 9: Epithelial lining of the urinary bladder is?
- A. Squamous epithelium
- B. Transitional epithelium (Correct Answer)
- C. Cuboidal epithelium
- D. Columnar epithelium
Explanation: ***Transitional epithelium*** - The urinary bladder is lined by **transitional epithelium**, also known as **urothelium** [1]. - This specialized epithelium can stretch and flatten when the bladder fills with urine, and then contract when it empties, a crucial adaptation for its function. *Squamous epithelium* - **Stratified squamous epithelium** is typically found in areas subject to abrasion, such as the skin, esophagus, and vagina. - It does not possess the unique distensibility required for the urinary bladder's function. *Cuboidal epithelium* - **Cuboidal epithelium** is commonly found in glands and kidney tubules, where it is involved in secretion and absorption. - It is not specialized for the significant stretching and recoiling seen in the urinary bladder. *Columnar epithelium* - **Columnar epithelium** is primarily involved in secretion and absorption and is found in regions like the gastrointestinal tract and some glandular ducts. - It lacks the necessary structural characteristics to accommodate the large volume changes of the urinary bladder.
Question 10: In articular cartilage, most active chondrocytes are seen in ?
- A. Zone 1
- B. Zone 4
- C. Zone 2 (Correct Answer)
- D. Zone 3
Explanation: ***Zone 2*** - The **transitional zone (Zone 2)** contains chondrocytes that are more metabolically active and contribute significantly to **collagen and proteoglycan synthesis**. [1] - These chondrocytes are typically **larger and more rounded** than those in the superficial layer and are organized in columns. *Zone 1* - **Zone 1 (superficial or tangential zone)** consists of **flattened chondrocytes** that are metabolically less active. - Its primary role is to resist **shear forces** and reduce friction. [1] *Zone 4* - **Zone 4 (calcified zone)** is the deepest layer of articular cartilage, characterized by **chondrocytes embedded in a calcified matrix**. - This zone anchors the cartilage to the subchondral bone and has **minimal metabolic activity**. *Zone 3* - **Zone 3 (deep or radial zone)** has chondrocytes arranged in **columns perpendicular to the articular surface**. [1] - While active in matrix production, their activity is generally **less pronounced** compared to the transitional zone.
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