Histopathology & Cytopathology: Tissue OmpathStudy

MOUNT KENYA UNIVERSITY — MEDICAL SCHOOL Programme: Bachelor of Medicine and Bachelor of Surgery, Year 3 Assessment: Mid Semester 1 — Continuous Assessment Test (CAT 1) Unit Code: MBPA 3511 Unit Title: Introduction to Histopathology and Cytopathology Date: 13th October 2025 Time: 22 minutes --- Q1. Which branch focuses on microscopic examination of tissues to diagnose disease? A. Microbiology B. Histopathology C. Immunology D. Pharmacology E. Biochemistry Answer: B — Histopathology By definition, this is the study of tissue changes caused by disease under the microscope. Others study organisms (A), immune responses (C), drugs (D), or chemical processes (E). Q2. Main function of epithelial tissue? A. Conducting electrical impulses B. Secretion and absorption C. Storing calcium D. Oxygen transport E. Enzyme synthesis Answer: B — Secretion and absorption Epithelium lines surfaces/glands for these functions. A is nervous tissue, C is bone, D is blood/RBCs, E is a general cellular process, not epithelium-specific. Q3. Stratified squamous epithelium is best adapted for: A. Diffusion B. Filtration C. Protection against abrasion D. Hormone secretion E. Energy storage Answer: C — Protection against abrasion Multiple cell layers resist mechanical wear (e.g., skin, oesophagus). Simple epithelia (single layer) are better for diffusion/filtration (A, B). Q4. Which muscle type is involuntary and non-striated? A. Skeletal B. Cardiac C. Smooth D. Voluntary E. Intercalated Answer: C — Smooth Found in viscera/vessels, lacks striations, involuntary control. Cardiac (B) is involuntary but striated; skeletal (A/D) is striated and voluntary; intercalated discs (E) are a cardiac muscle feature, not a muscle type. Q5. Nervous tissue mainly comprises: A. Fibroblasts and collagen B. Neurons and glial cells C. Osteocytes and chondrocytes D. Keratinocytes and melanocytes E. Myocytes and sarcomeres Answer: B — Neurons and glial cells These are the two principal cell types of nervous tissue. Others belong to connective tissue (A), bone/cartilage (C), skin (D), and muscle (E). Q6. Primary purpose of tissue fixation? A. To stain cells B. To preserve cellular structure C. To embed tissue in paraffin D. To remove water from tissue E. To decalcify bone Answer: B — To preserve cellular structure Fixation halts autolysis/decay and stabilises architecture. C and D are separate processing steps; E is a distinct procedure for bony tissue. Q7. Most commonly used fixative in histopathology? A. Methanol B. Glutaraldehyde C. Formalin (formaldehyde) D. Osmium tetroxide E. Acetic acid Answer: C — Formalin (formaldehyde) Standard routine fixative for light microscopy. Glutaraldehyde (B) and osmium tetroxide (D) are used for electron microscopy. Q8. A good fixative should: A. Produce numerous artefacts B. Delay penetration C. Preserve tissue morphology D. Destroy proteins E. Be incompatible with staining Answer: C — Preserve tissue morphology This is the core requirement of any fixative. All other options describe undesirable fixative properties. Q9. Which fixative is preferred for electron microscopy due to ultrastructural preservation? A. Formalin B. Glutaraldehyde C. Ethanol D. Methanol E. Bouin's solution Answer: B — Glutaraldehyde Cross-links proteins extensively, giving superior ultrastructural detail needed at EM resolution. Formalin (A) is adequate for light microscopy only. Q10. Osmium tetroxide primarily fixes: A. Proteins B. Lipids and membranes C. Nucleic acids D. Carbohydrates E. Enzymes Answer: B — Lipids and membranes It preserves membrane lipid bilayers, important for EM. It doesn't primarily target proteins/nucleic acids (A, C). Q11. Purpose of tissue decalcification? A. Preserve nucleic acids B. Remove calcium salts C. Stain nuclei D. Increase embedding speed Answer: B — Remove calcium salts Necessary before sectioning bone, so the microtome blade can cut through it (calcium salts make tissue too hard otherwise). Q12. Which agent is a chelating decalcifier? A. Nitric acid B. Hydrochloric acid C. Formic acid D. EDTA E. Acetic acid Answer: D — EDTA EDTA chelates (binds) calcium ions slowly without damaging tissue. A, B, C are acid decalcifiers, which work faster but cause more tissue damage. Q13. Main disadvantage of acid decalcification? A. Too slow B. Tissue damage and loss of detail C. No calcium removal D. Poor embedding E. Non-uniform penetration Answer: B — Tissue damage and loss of detail Acids decalcify quickly but can damage cellular/nuclear detail, unlike the gentler EDTA method. Q14. Which embedding medium is standard for light microscopy? A. Resin B. Paraffin wax C. Agar D. Gelatin E. Collagen Answer: B — Paraffin wax Standard, cost-effective medium allowing thin sectioning for routine light microscopy. Resin (A) is used for EM/very thin sections. Q15. Which processing step involves replacing water with alcohol? A. Fixation B. Dehydration C. Clearing D. Embedding E. Mounting Answer: B — Dehydration Uses increasing alcohol conce