Histology and Cytology Basics
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Questions and Answers

What is the primary function of the nucleus in a eukaryotic cell?

  • Structural support
  • Energy production
  • Genetic control center (correct)
  • Storage of nutrients

    • Which of the following is considered a membranous organelle?

  • Mitochondria (correct)
  • Ribosome
  • Filament
  • Microtubule

    • What mainly composes the cytosol in a cell?

  • Carbohydrates
  • Nucleic acids
  • Water (correct)
  • Proteins

    • Which of the following organelles is responsible for protein synthesis?

    <p>Endoplasmic reticulum</p> Signup and view all the answers

    What is the structural characteristic of the cell membrane?

    <p>Trilaminar appearance with lipids as the main constituent</p> Signup and view all the answers

    What type of organelles are ribosomes classified as?

    <p>Non-membranous organelles</p> Signup and view all the answers

    Which structure is NOT essential for the vitality of a cell?

    <p>Inclusions</p> Signup and view all the answers

    What is the typical thickness of the average cell membrane as seen under an electron microscope?

    <p>7.5 nm</p> Signup and view all the answers

    What structure of phospholipids is primarily responsible for the cell membrane's dark staining appearance in electron microscopy?

    <p>The polar head of the phospholipids</p> Signup and view all the answers

    What is the role of cholesterol in the cell membrane?

    <p>To provide stability to the membrane</p> Signup and view all the answers

    Which statement is true regarding glycolipids?

    <p>They are present only on the outer surface of cell membranes</p> Signup and view all the answers

    What function does the glycocalyx serve in the cell membrane?

    <p>It acts as a protective barrier</p> Signup and view all the answers

    What is the primary mechanism of simple diffusion described in the content?

    <p>Movement down a concentration gradient</p> Signup and view all the answers

    What is the primary reason that molecules in the glycocalyx are negatively charged?

    <p>To maintain a repulsion between adjacent cells</p> Signup and view all the answers

    How do glycoproteins and glycolipids contribute to the cell membrane?

    <p>By forming the cell coat or glycocalyx</p> Signup and view all the answers

    Which of the following best describes the arrangement of phospholipids in the cell membrane?

    <p>Two layers with hydrophilic heads facing outward</p> Signup and view all the answers

    What is the frequent cause of jaundice in newborn infants?

    <p>Underdeveloped state of SER in liver cells</p> Signup and view all the answers

    Which part of the Golgi complex faces the nucleus?

    <p>Cis Face</p> Signup and view all the answers

    What are lysosomes primarily known for?

    <p>Rubbish disposal unit of the cell</p> Signup and view all the answers

    How are lysosomal enzymes modified and packed?

    <p>They are synthesized in RER and modified in the Golgi complex</p> Signup and view all the answers

    What defines the primary lysosomes?

    <p>They have not entered into a digestive process</p> Signup and view all the answers

    What is a major function of the Golgi complex?

    <p>Modifying proteins by adding carbohydrates and phosphates</p> Signup and view all the answers

    What visual representation is used to identify the Golgi complex?

    <p>Non-stained area known as Negative Golgi Image</p> Signup and view all the answers

    What are transfer vesicles derived from?

    <p>Rough endoplasmic reticulum</p> Signup and view all the answers

    What is the primary role of the nucleolus within the nucleus?

    <p>It is involved in ribosome production.</p> Signup and view all the answers

    Which feature distinguishes the outer nuclear membrane from the inner nuclear membrane?

    <p>The outer membrane is continuous with the rough endoplasmic reticulum.</p> Signup and view all the answers

    Exogenous pigments include which of the following substances?

    <p>Carotene pigment</p> Signup and view all the answers

    Which of the following functions is NOT performed by the nuclear membrane?

    <p>Coordination of cell activities</p> Signup and view all the answers

    What defines a eukaryotic cell's nucleus?

    <p>It contains the cell's genetic material?</p> Signup and view all the answers

    What is the function of the nuclear pore complex?

    <p>To control the movement of substances across the nuclear envelope.</p> Signup and view all the answers

    Which type of crystals accumulate in cells due to protein metabolism, particularly in gout disease?

    <p>Uric acid crystals</p> Signup and view all the answers

    What does the chromatin within the nucleus primarily consist of?

    <p>DNA and proteins</p> Signup and view all the answers

    What is the primary purpose of fixation in tissue preparation?

    <p>To harden tissue for easier cutting</p> Signup and view all the answers

    Which step follows the dehydration of tissue in the preparation process?

    <p>Clearing with xylene</p> Signup and view all the answers

    What is the purpose of using xylene in the tissue preparation process?

    <p>To act as a paraffin solvent and make tissue transparent</p> Signup and view all the answers

    What is the role of paraffin wax in the impregnation and embedding process?

    <p>It fills spaces previously occupied by water</p> Signup and view all the answers

    Which of the following methods is considered faster for tissue preparation?

    <p>Freezing technique using liquid nitrogen</p> Signup and view all the answers

    During staining, what must happen to the wax before the tissue sections can be stained?

    <p>It must be replaced with water</p> Signup and view all the answers

    What thickness do serial sections cut by a microtome typically have?

    <p>5-7 µm</p> Signup and view all the answers

    What is the staining characteristic of Hematoxylin?

    <p>It stains acidic components giving a blue color</p> Signup and view all the answers

    What is the primary function of kinetochores in cell division?

    <p>To attach spindle fibers for pulling apart sister chromatids</p> Signup and view all the answers

    Which of the following correctly describes telomeres?

    <p>They consist of the sequence TTAGGG and protect chromosome ends.</p> Signup and view all the answers

    What is the haploid number of chromosomes in humans?

    <p>23</p> Signup and view all the answers

    How are chromosomes typically classified based on centromere position?

    <p>Metacentric, Submetacentric, Acrocentric, and Telocentric</p> Signup and view all the answers

    What does karyotyping analyze?

    <p>The complete set of metaphase chromosomes arranged by size</p> Signup and view all the answers

    Which syndromes can be identified through karyotyping?

    <p>Trisomy 21 (Down syndrome) and Turner syndrome (45, X0)</p> Signup and view all the answers

    What characterizes diploid cells in humans?

    <p>They contain two sets of chromosomes.</p> Signup and view all the answers

    In humans, what is the composition of the 23rd pair of chromosomes?

    <p>One X and one Y chromosome in males</p> Signup and view all the answers

    Study Notes

    Histology and Cytology

    • Histology is the study of tissues, and cytology is the study of cells.
    • Examining structures with increasing magnification requires microscopes.

    Types of Microscopes

    • Light microscopes allow observation of specimens in their natural state.
    • Electron microscopes allow for greater resolution, but specimens must be dead.

    Parts of a Light Microscope

    • Eyepiece
    • Body tube
    • Nosepiece
    • Low power objective lens
    • Medium power objective lens
    • High power objective lens
    • Stage clips
    • Diaphragm
    • Light source
    • Arm
    • Stage
    • Coarse adjustment knob
    • Fine adjustment knob
    • Base

    Comparison of Light and Electron Microscope

    • Light microscopes are relatively inexpensive, and specimens can be alive and unharmed.
    • Electron microscopes require training, are expensive and non-portable, and specimens must be dead.
    • Light microscopes produce colored images.
    • Electron microscopes produce black and white images.
    • Light microscopes have lower resolving power and lower magnification than electron microscopes.

    Methods of Studying Cells and Tissues

    • Microtechniques are used for tissue preparation for microscopic observation.
    • The paraffin technique is a common method involving fixation, washing, dehydration, clearing, impregnation, embedding, sectioning, mounting, and staining.
    • Alternative method of observation involves freezing sections.

    The Cell

    • The cell is the basic functional and structural unit of all living tissues.
    •  Cell size varies, but the smallest cell is a sperm cell, measuring 5 µm
    •  The largest cell is an ovum, measuring 120 µm.
    • The longest cell is a nerve cell, measuring 1m

    Structure of the Cell

    • Nucleus: the control center of the eukaryotic cell.
    • Cytoplasm: The jelly-like substance containing organelles and inclusions.
    • Organelles: Small structures with specific functions in the cell.
    • Inclusions: Non -essential cell components.

    Cell Membranes

    • The plasma membrane is a thin, flexible barrier separating the cell from its external environment.
    • The cell membrane is predominantly composed of lipids, proteins, and carbohydrates.
    • Cholesterol contributes to membrane stability.
    • Glycolipids are located exclusively on the outer plasma membrane surface.
    • Proteins form channels, receptors, and other essential components.
    • Carbohydrates form a cell coat that participates in cell-cell interactions.

    Functions of the Cell Membrane

    • Passive transport: Movement of substances across a membrane without energy expenditure.
    • Active transport: Movement of substances against their concentration gradient requiring energy.
    • Bulk transport (Endocytosis and Exocytosis): Larger molecule transport.

    Mitochondria

    • These organelles convert organic molecules into cellular energy (ATP)
    • Contain their own DNA and ribosomes.
    • Located in the matrix portion of the cell.
    • Mitochondria use organic materials to produce energy.
    • Mitochondria play a role in calcium regulation and apoptosis.

    Endoplasmic Reticulum

    • The ER is a network of interconnected membranes forming tubules and flattened sacs called cisternae.
    • Rough ER incorporates ribosomes on its surface, involved in protein synthesis.
    • Smooth ER lacks ribosomes, involved in lipid synthesis, detoxification, and calcium storage.

    Golgi Apparatus

    • Processes, packages, and sorts molecules, and helps with macromolecule synthesis.
    • It plays a role in lysosome formation.

    Lysosomes

    • These membranous organelles have hydrolytic enzymes for intracellular digestion.
    • They help break down worn-out organelles, bacteria, and damaged cells

    Peroxisomes

    • They contain enzymes for lipid metabolism.
    • Peroxisomes form hydrogen peroxide which degrades toxic molecules.

    Ribosomes

    • Ribosomes are non-membrane-bound organelles.
    • Ribosomes synthesize proteins.

    Centrioles

    •  Centrioles appear as a pair of cylindrical rods at right angles to each other.
    • The centrioles form the mitotic spindle during cell division.
    • Centrioles are essential for forming cilia and flagella.

    Cytoskeleton

    • The cytoskeleton is the internal scaffolding of the cell and determines its shape.
    • It is involved in organelle movement, cell motility, and intracellular transport.
    • The cytoskeleton is composed of microtubules, microfilaments, and intermediate filaments.

    Cytoplasmic Inclusions

    • Non-living structures not essential for cell growth.
    • Inclusions can be stored food, pigments, and crystals

    Glycogen

    • Carbohydrate stored in cells as energy reserve
    • Staining methods are used to visualize glycogen within cells

    Pigments

    • Endogenous pigments are formed within cells (e.g., melanin).
    • Exogenous pigments originate outside the cell (e.g., tattoo ink).

    Nucleus

    • The cell's control center, it encloses DNA, which contains the cell's genetic instructions.
    • The nucleus is composed of a nuclear envelope with pores for transport.
    • Within the nucleus is the nucleolus, which produces ribosomes, and chromatin
    • Chromatin consists of DNA packaged with proteins to form chromosomes.

    Chromosomes

    • Chromosomes are structures carrying DNA and proteins.
    • Chromosomes are visible during cell division.

    Karyotyping

    • Karyotyping refers to the analysis of chromosomes using microscopy for diagnosis of genetic disorders.

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    Histology and Cytology PDF

    Description

    Explore the fundamentals of histology and cytology through this quiz. Learn about the various types of microscopes, their components, and the differences between light and electron microscopes. Perfect for students aiming to understand tissue and cell structure at a microscopic level.

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