HISTOLOGY EXAM 1

Module 1: Microscopy & Tissue Basics (13 Questions)

  • Definition of Tissue: A group of similar cells working together to perform a specific function.

  • Tissue Fixation Steps:

    • Fixation (e.g., formalin) to preserve tissue.

    • Dehydration (e.g., ethanol) to remove water.

    • Clearing (e.g., xylene) to make tissue transparent.

    • Embedding (e.g., paraffin wax) for sectioning.

    • Sectioning (thin slices made with a microtome).

    • Staining (e.g., H&E, PAS) for visualization.

  • Microscopy Resolution: The ability to distinguish two closely spaced structures as separate.

  • Types of Microscopy:

    • Light Microscopy (LM): Uses visible light; commonly used in histology.

    • Transmission Electron Microscopy (TEM): High-resolution, shows internal cell structures.

    • Scanning Electron Microscopy (SEM): Produces 3D surface images.

  • Stains Used in Micrographs:

    • Hematoxylin & Eosin (H&E): Hematoxylin stains nuclei blue/purple, Eosin stains cytoplasm pink.

    • Periodic Acid-Schiff (PAS): Stains carbohydrates/mucins (e.g., goblet cells).

    • Masson’s Trichrome: Stains collagen blue/green.

  • Organelle Identification:

    • Nucleus: Dark-stained in H&E.

    • Mitochondria: Small, numerous in TEM.

    • Golgi Apparatus: Clear area near the nucleus.



Module 2: Epithelial Tissue Structure & Specializations (12 Questions)

  • Four Tissue Types & Descriptions:

    • Epithelial: Covers body surfaces, lines cavities.

    • Connective: Supports and binds tissues.

    • Muscle: Contracts to produce movement.

    • Nervous: Transmits electrical signals.

  • Epithelial Cell Surfaces:

    • Apical (top): Faces lumen/external environment.

    • Basal (bottom): Attaches to basement membrane.

    • Lateral (side): Connects to neighboring cells.

  • Apical Specializations:

    • Microvilli: Increase absorption (e.g., intestine).

    • Cilia: Move substances (e.g., respiratory tract).

  • Intercellular Junctions:

    • Tight Junctions: Prevent leakage.

    • Adherens Junctions: Provide structural support.

    • Desmosomes: Resist mechanical stress.

    • Gap Junctions: Allow communication.

  • True/False Concept: A single epithelial cell can have multiple intercellular junctions.



Module 3: Epithelium Identification & Locations (13 Questions)

  • Characteristics of Epithelial Cells:

    • Cell shape (squamous, cuboidal, columnar).

    • Layering (simple, stratified, pseudostratified).

  • Common Epithelial Types & Locations:

    • Simple Squamous: Lungs (alveoli), blood vessels.

    • Simple Cuboidal: Kidney tubules, glands.

    • Simple Columnar: GI tract (intestines).

    • Pseudostratified Columnar: Respiratory tract.

    • Stratified Squamous: Skin, esophagus.

    • Transitional: Bladder.



Module 4: Connective Tissue Identification & Locations (20 Questions)

  • Major Connective Tissue Types:

    • Loose (Areolar): Under epithelial layers.

    • Dense Regular: Tendons, ligaments.

    • Dense Irregular: Dermis, organ capsules.

    • Adipose: Fat storage, insulation.

    • Reticular: Lymphoid organs.

    • Cartilage (Hyaline, Elastic, Fibrocartilage): Joints, ears, intervertebral discs.

    • Bone: Skeletal support.

Blood: Fluid connective tissue.