Stratified epithelial tissues US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Stratified epithelial tissues. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Stratified epithelial tissues US Medical PG Question 1: A pathologist examining a tissue sample notes the presence of pseudostratified columnar epithelium with goblet cells and cilia. This tissue was most likely obtained from which of the following locations?
- A. Bronchi (Correct Answer)
- B. Small intestine
- C. Skin
- D. Esophagus
- E. Urinary bladder
Stratified epithelial tissues Explanation: ***Bronchi***
- The **bronchi**, as part of the respiratory tract, are lined with **pseudostratified columnar epithelium** that contains abundant **goblet cells** and **cilia** [1].
- **Cilia** help propel mucus and trapped particles out of the respiratory system, while **goblet cells** produce mucus to trap foreign substances [1].
*Small intestine*
- The small intestine is lined with **simple columnar epithelium** with **microvilli** (forming a brush border) and goblet cells, but it lacks **cilia**.
- Its primary function is nutrient absorption, not particulate clearance.
*Skin*
- The skin is covered by **stratified squamous epithelium**, specifically **keratinized stratified squamous epithelium**, which provides protection against abrasion and dehydration.
- It does not contain **goblet cells**, **cilia**, or **pseudostratified columnar epithelium**.
*Esophagus*
- The esophagus is lined with **non-keratinized stratified squamous epithelium**, designed to protect against mechanical abrasion during food passage.
- It lacks **goblet cells**, **cilia**, and **pseudostratified columnar epithelium**.
Stratified epithelial tissues US Medical PG Question 2: A 65-year-old man with a 40-pack-year smoking history presents with hemoptysis and a persistent cough. Chest CT shows a 3.5 cm centrally located mass in the right main bronchus. Positron emission tomography confirms a malignant nodule. Bronchoscopy with transbronchial biopsy is performed and a specimen sample of the nodule is sent for frozen section analysis. The tissue sample is most likely to show which of the following tumor types?
- A. Carcinoid tumor
- B. Metastasis of colorectal cancer
- C. Small cell lung carcinoma
- D. Large cell carcinoma
- E. Squamous cell carcinoma (Correct Answer)
Stratified epithelial tissues Explanation: ***Squamous cell carcinoma***
- This is the most likely diagnosis given the **central location** in the main bronchus, **heavy smoking history**, and presentation with **hemoptysis**.
- **Squamous cell carcinoma** accounts for 25-30% of lung cancers and characteristically arises in **central/proximal airways**, making it readily accessible by **bronchoscopy**.
- Histologically, it shows **keratin pearls** and **intercellular bridges** on biopsy.
- The **central endobronchial location** and ability to obtain tissue via transbronchial biopsy strongly favor squamous cell over peripheral tumors.
*Carcinoid tumor*
- **Carcinoid tumors** are **neuroendocrine tumors** that can present as central endobronchial masses and cause hemoptysis.
- However, they are typically **slow-growing** with more indolent presentation, and PET scans show **variable uptake** (often less intense than aggressive carcinomas).
- They represent only **1-2% of lung tumors** and occur more commonly in **younger, non-smoking patients**.
*Metastasis of colorectal cancer*
- While lung is a common site for **colorectal metastases**, these typically present as **multiple peripheral nodules** rather than a solitary central endobronchial mass.
- The clinical presentation strongly suggests **primary lung cancer** rather than metastatic disease.
- Without history of colorectal cancer, this is unlikely.
*Small cell lung carcinoma*
- **Small cell lung carcinoma** (SCLC) represents 15% of lung cancers and typically presents as a **large central mass** with early mediastinal involvement.
- However, SCLC is usually **too extensive at presentation** for transbronchial biopsy alone and often requires mediastinoscopy or CT-guided biopsy.
- Histology shows **small cells with scant cytoplasm**, **salt-and-pepper chromatin**, and **oat-cell morphology**.
- While possible, the single accessible endobronchial mass is more characteristic of squamous cell.
*Large cell carcinoma*
- **Large cell carcinoma** is a **diagnosis of exclusion** made when tumors lack features of adenocarcinoma, squamous cell, or small cell differentiation.
- It typically presents as **large peripheral masses** rather than central endobronchial lesions.
- It represents only **10% of lung cancers** and is less common than squamous cell carcinoma in this clinical scenario.
Stratified epithelial tissues US Medical PG Question 3: A researcher is studying proteins that contribute to intestinal epithelial permeability. He has isolated intestinal tissue from several mice. After processing the tissue into its individual components, he uses a Western blot analysis to identify a protein that forms part of a multi-protein complex at the apical aspect of epithelial cells. The complex is known to provide a diffusion barrier between the apical and basolateral aspects of epithelial cells. Which of the following proteins is this researcher most likely investigating?
- A. Integrin
- B. Connexon
- C. Desmoglein
- D. E-cadherin
- E. Claudin (Correct Answer)
Stratified epithelial tissues Explanation: ***Claudin***
- **Claudins** are integral membrane proteins that are primary components of **tight junctions** (zonulae occludentes), which form a diffusion barrier at the **apical aspect** of epithelial cells.
- They regulate **paracellular permeability**, crucial for maintaining the integrity of the intestinal epithelial barrier.
*Integrin*
- **Integrins** are transmembrane receptors that mediate cell-extracellular matrix (ECM) adhesion and cell-cell adhesion, but they are not the primary components of tight junction diffusion barriers.
- They are involved in cell signaling and structural support, rather than forming a direct paracellular seal.
*Connexon*
- A **connexon** is a protein assembly that forms a **gap junction**, allowing direct communication and passage of small molecules between adjacent cells.
- Gap junctions facilitate intercellular communication, but do not primarily contribute to sealing the paracellular space as a diffusion barrier.
*Desmoglein*
- **Desmoglein** is a cadherin family protein found in **desmosomes** (maculae adherens), which are cell-cell adhesion complexes that provide strong mechanical attachments between cells.
- Desmosomes resist shearing forces and provide structural integrity but do not regulate paracellular permeability as tight junctions do.
*E-cadherin*
- **E-cadherin** is a crucial component of **adherens junctions** (zonula adherens), which provide cell-cell adhesion and help establish and maintain cell polarity.
- While important for epithelial integrity, E-cadherin primarily links cells to the actin cytoskeleton and is not directly responsible for forming the selective diffusion barrier itself.
Stratified epithelial tissues US Medical PG Question 4: A 48-year-old man has smoked approximately 3 packs of cigarettes per day for the past 12 years. Which of the following pathologic changes is most likely to occur in his bronchial epithelium?
- A. Metaplasia (Correct Answer)
- B. Hyperplasia
- C. Hypertrophy
- D. Dysplasia
- E. Atrophy
Stratified epithelial tissues Explanation: ***Metaplasia***
- Chronic irritation from **cigarette smoking** can cause the **bronchial epithelium** to change from ciliated columnar to stratified squamous, a process known as **metaplasia**.
- This adaptation makes the tissue more resistant to injury but results in the loss of important protective functions like **mucociliary clearance**.
*Hyperplasia*
- **Hyperplasia** involves an increase in the number of cells in a tissue or organ, often in response to increased demand or chronic stimulation.
- While smoking can cause hyperplasia of goblet cells and mucous glands in the bronchi, the direct epithelial change in response to chronic irritation is more specifically **metaplasia**.
*Hypertrophy*
- **Hypertrophy** is an increase in the size of individual cells, leading to an increase in the size of the organ or tissue.
- This is not the primary adaptive change seen in the bronchial epithelium in response to chronic smoking; instead, cells change their type.
*Dysplasia*
- **Dysplasia** refers to disorderly cell growth, often characterized by variations in cell size, shape, and organization; it is considered a precursor to cancer.
- While chronic smoking can eventually lead to dysplasia and then carcinoma, the initial and most common adaptive change in the bronchial epithelium is **metaplasia**.
*Atrophy*
- **Atrophy** is a decrease in cell size or number, leading to a reduction in the size of an organ or tissue, usually due to decreased workload, nutrition, or blood supply.
- This is not a typical response of the bronchial epithelium to chronic irritation from smoking, which tends to induce proliferative or adaptive changes.
Stratified epithelial tissues US Medical PG Question 5: Research is being conducted on embryoblasts. The exact date of fertilization is unknown. There is the presence of a cytotrophoblast and syncytiotrophoblast, marking the time when implantation into the uterus would normally occur. Within the embryoblast, columnar and cuboidal cells are separated by a membrane. Which of these cell layers begins to line the yolk sac cavity?
- A. Hypoblast (Correct Answer)
- B. Epiblast
- C. Syncytiotrophoblast
- D. Inner cell mass
- E. Endoderm
Stratified epithelial tissues Explanation: ***Hypoblast***
- The **hypoblast** is a layer of cuboidal cells that forms from the inner cell mass around day 8 post-fertilization.
- It plays a crucial role in forming the **primary yolk sac** by migrating to line the exocoelomic cavity.
*Epiblast*
- The **epiblast** is composed of columnar cells located dorsal to the hypoblast and forms the floor of the **amniotic cavity**.
- It is the source of the **three primary germ layers** during gastrulation (ectoderm, mesoderm, and endoderm), not the yolk sac lining itself.
*Syncytiotrophoblast*
- The **syncytiotrophoblast** is the outer, invasive layer of the trophoblast that facilitates implantation and forms the fetal component of the placenta.
- It is not involved in lining the yolk sac cavity but rather in **invading the uterine endometrium** and producing hCG.
*Inner cell mass*
- The **inner cell mass (ICM)** is the cluster of cells within the blastocyst that gives rise to the embryoblast (which further differentiates into epiblast and hypoblast).
- The ICM itself does not line the yolk sac; rather, its derivative, the hypoblast, does.
*Endoderm*
- The **endoderm** is one of the three primary germ layers that forms during gastrulation from the epiblast derivative.
- It ultimately forms the linings of the **gastrointestinal and respiratory tracts**, not the primary yolk sac lining.
Stratified epithelial tissues US Medical PG Question 6: A 67-year-old man comes to the physician because of urinary frequency, dysuria, and blood in his urine. He has also had a 4.5-kg (10-lb) weight loss over the past 3 months and has been feeling more fatigued than usual. He smoked one pack of cigarettes daily for 40 years but quit 2 years ago. A urinalysis shows 3+ blood. Cystoscopy shows an irregular mass on the bladder wall; a biopsy is taken. Which of the following histologic findings would indicate the worst survival prognosis?
- A. Disordered urothelium lined with papillary fronds
- B. Dysplastic cells extending into the lamina propria
- C. Infiltrating nests of cells with squamous differentiation
- D. Nests of atypical cells in the urothelium
- E. Tubular glands with mucin secretions (Correct Answer)
Stratified epithelial tissues Explanation: ***Tubular glands with mucin secretions***
- The presence of **tubular glands with mucin secretions** indicates a diagnosis of **adenocarcinoma of the bladder**.
- Bladder adenocarcinoma is a rare and aggressive form of bladder cancer with a **significantly worse prognosis** compared to urothelial carcinoma, comprising <2% of bladder cancers and often presenting at advanced stages with limited treatment options.
*Dysplastic cells extending into the lamina propria*
- This description refers to **high-grade urothelial carcinoma** that has invaded the **lamina propria** (stage T1).
- While it's an invasive cancer with significant risk, it generally has a better prognosis than adenocarcinoma when treated appropriately.
*Disordered urothelium lined with papillary fronds*
- This suggests a **papillary urothelial neoplasm**, which could be low-grade or high-grade.
- Early-stage papillary tumors generally have a favorable prognosis, especially low-grade variants.
*Nests of atypical cells in the urothelium*
- This finding describes **carcinoma in situ (CIS)**, a high-grade, flat, non-invasive form of urothelial carcinoma.
- Although it has a high risk of progression to invasive cancer, it does not inherently indicate a worse prognosis than invasive adenocarcinoma at the time of diagnosis.
*Infiltrating nests of cells with squamous differentiation*
- This describes **squamous cell carcinoma of the bladder**, which accounts for 3-5% of bladder cancers.
- While aggressive and often associated with chronic irritation or schistosomiasis, it generally has a better prognosis than adenocarcinoma when detected and treated early.
Stratified epithelial tissues US Medical PG Question 7: A lung mass of a 50 pack-year smoker is biopsied. If ADH levels were grossly increased, what would most likely be the histologic appearance of this mass?
- A. Layered squamous cells with keratin pearls
- B. Pleomorphic giant cells with leukocyte fragments in cytoplasm
- C. Hyperplasia of mucin producing glandular tissue
- D. Tall columnar cells bordering the alveolar septum
- E. Sheets of small round cells with hyperchromatic nuclei (Correct Answer)
Stratified epithelial tissues Explanation: ***Sheets of small round cells with hyperchromatic nuclei***
- Grossly increased **ADH levels** in a smoker suggest **syndrome of inappropriate antidiuretic hormone (SIADH)**, which is commonly associated with **small cell lung carcinoma (SCLC)**.
- SCLC is characterized histologically by sheets of **small (lymphocyte-like) cells** with scant cytoplasm and **hyperchromatic nuclei**.
*Layered squamous cells with keratin pearls*
- This description corresponds to **squamous cell carcinoma**, which is associated with smoking but typically causes **hypercalcemia** due to parathyroid hormone-related peptide (PTHrP) production, not elevated ADH.
- Key histological features are **keratin pearls** and **intercellular bridges**.
*Pleomorphic giant cells with leukocyte fragments in cytoplasm*
- This describes **large cell carcinoma**, which is a diagnosis of exclusion and does not typically manifest with paraneoplastic SIADH.
- **Large cell carcinoma** is characterized by large, anaplastic cells without differentiation towards squamous, glandular, or small cell features.
*Hyperplasia of mucin producing glandular tissue*
- This appearance is characteristic of **adenocarcinoma**, which often arises in non-smokers and is not typically associated with SIADH.
- **Adenocarcinoma** exhibits glandular differentiation and often produces mucin.
*Tall columnar cells bordering the alveolar septum*
- This refers to **lepidic growth pattern** often seen in some subtypes of **adenocarcinoma (e.g., adenocarcinoma in situ or minimally invasive adenocarcinoma)**.
- While it is a type of lung cancer, it is not primarily associated with SIADH as a paraneoplastic syndrome.
Stratified epithelial tissues US Medical PG Question 8: A 19-month-old girl is brought by her mother to the local walk-in clinic after noticing a mass protruding from her vagina. The mass had the appearance of "a bunch of grapes". She also says that she has been having a vaginal discharge for the past 6 months. Her family and personal history are not significant for malignancies or inherited disorders. The physical examination is unremarkable except for the presence of soft nodules protruding from the vaginal canal. A tissue sample is obtained for histologic evaluation. Several weeks later the patient returns to the walk-in clinic for a scheduled follow-up visit. The pathology report describes a polypoid mass beneath an epithelial surface with atypical stromal cells positive for polyclonal desmin. What is the most likely diagnosis in this patient?
- A. Squamous cell carcinoma (SCC)
- B. Verrucous carcinoma
- C. Sarcoma (Correct Answer)
- D. Adenocarcinoma
- E. Melanoma
Stratified epithelial tissues Explanation: ***Sarcoma***
- The description of a **"bunch of grapes"** mass in a young girl, along with **atypical stromal cells** positive for **polyclonal desmin**, is highly characteristic of **embryonal rhabdomyosarcoma** (a type of sarcoma botryoides).
- **Desmin positivity** indicates a muscle cell origin, and the **polypoid mass** is consistent with the gross appearance of this aggressive childhood tumor.
*Squamous cell carcinoma (SCC)*
- SCC of the vagina is extremely rare in a **19-month-old girl** and typically affects older women.
- Histologically, SCC would show **dysplastic squamous epithelial cells** with **keratinization** or intercellular bridges, not atypical stromal cells positive for desmin.
*Verrucous carcinoma*
- This is a rare, well-differentiated variant of SCC, also typically occurring in **older individuals** and associated with HPV infection.
- It presents as a **warty, exophytic lesion** with minimal cellular atypia, distinct from a "bunch of grapes" mass and desmin positivity.
*Adenocarcinoma*
- Vaginal adenocarcinoma can occur in young girls, particularly **clear cell adenocarcinoma** associated with **diethylstilbestrol (DES) exposure**; however, this patient has no such history.
- Histology would show glandular differentiation and mucin production, not atypical stromal cells expressing desmin.
*Melanoma*
- Vaginal melanoma is very rare, typically presenting as a **pigmented lesion** in postmenopausal women.
- Histopathology would reveal malignant melanocytes with **positive S-100 and HMB-45 staining**, not atypical stromal cells positive for desmin.
Stratified epithelial tissues US Medical PG Question 9: A 35-year-old woman presents to a pre-operative evaluation clinic prior to an elective cholecystectomy. She has a 5 pack-year smoking history. The anesthesiologist highly recommends to discontinue smoking for at least 8 weeks prior to the procedure for which she is compliant. What is the most likely histology of her upper respiratory tract's epithelial lining at the time of her surgery?
- A. Simple squamous
- B. Simple columnar
- C. Pseudostratified columnar (Correct Answer)
- D. Stratified squamous
- E. Stratified columnar
Stratified epithelial tissues Explanation: ***Pseudostratified columnar***
- The upper respiratory tract is normally lined by **pseudostratified ciliated columnar epithelium** with goblet cells, which is crucial for mucociliary clearance.
- While smoking can initially cause **squamous metaplasia**, discontinuing smoking for 8 weeks allows for significant, if not complete, **reversal of these changes** back to the normal pseudostratified columnar epithelium.
*Simple squamous*
- This type of epithelium is found in areas designed for efficient **gas exchange** (e.g., alveoli of the lungs) and is not typical for the conductive airways of the upper respiratory tract.
- It lacks the **cilia and goblet cells** necessary for clearing inhaled particles and pathogens.
*Simple columnar*
- **Simple columnar epithelium** is found in regions like the lining of the gastrointestinal tract (e.g., stomach, small and large intestines) and is not characteristic of the upper respiratory tract.
- While it can have goblet cells, it typically lacks **cilia** for respiratory clearance.
*Stratified squamous*
- **Stratified squamous epithelium** is found in areas subject to friction and abrasion, such as the oral cavity, pharynx, and esophagus.
- While chronic smoking can induce **squamous metaplasia** in the respiratory tract, an 8-week cessation period would likely result in the reversal of this change back to the normal type.
*Stratified columnar*
- **Stratified columnar epithelium** is a relatively rare type found in specific locations like parts of the male urethra and some large excretory ducts.
- It is not the normal or even a common metaplastic lining for the human upper respiratory tract.
Stratified epithelial tissues US Medical PG Question 10: A 55-year-old woman comes to the physician because of a 2-week history of painful swelling on the right side of her face. The pain worsens when she eats. Examination of the face shows a right-sided, firm swelling that is tender to palpation. Oral examination shows no abnormalities. Ultrasonography shows a stone located in a duct that runs anterior to the masseter muscle and passes through the buccinator muscle. Sialoendoscopy is performed to remove the stone. At which of the following sites is the endoscope most likely to be inserted during the procedure?
- A. Lateral to the lingual frenulum
- B. Into the floor of the mouth
- C. Lateral to the superior labial frenulum
- D. Into the mandibular foramen
- E. Opposite the second upper molar tooth (Correct Answer)
Stratified epithelial tissues Explanation: ***Opposite the second upper molar tooth***
- The description of the duct running anterior to the **masseter muscle** and through the **buccinator muscle** is characteristic of the **parotid duct (Stensen's duct)**.
- The parotid duct opens into the oral cavity on the buccal mucosa **opposite the second upper molar tooth**, which is the most likely entry point for sialoendoscopy to remove a stone from this duct.
*Lateral to the lingual frenulum*
- This location is where the **submandibular duct (Wharton's duct)** opens into the oral cavity.
- While stones can occur in the submandibular duct, the patient's symptoms and the duct's anatomical description do not match this location.
*Into the floor of the mouth*
- The floor of the mouth is the general area where the submandibular and sublingual ducts open.
- However, the specific anatomical description of the duct in relation to the masseter and buccinator muscles points away from the submandibular/sublingual glands.
*Lateral to the superior labial frenulum*
- This area is associated with the openings of minor salivary glands in the upper lip.
- These glands are typically too small to be the source of such a prominent swelling or a large stone requiring sialoendoscopy.
*Into the mandibular foramen*
- The **mandibular foramen** is an opening on the medial surface of the mandibular ramus.
- It is an anatomical landmark for the **inferior alveolar nerve and vessels** and has no direct involvement in salivary gland duct openings.
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