Cell Biology Basics
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Questions and Answers

The part of the microscope where the glass slide is placed is called the ________.

stage

Which type of microscope uses ultraviolet (UV) light as the source of light?

  • Darkfield microscope
  • Electron microscope
  • Fluorescence microscope (correct)
  • Brightfield microscope

    • The cell membrane is composed of only lipids.

    False

    State one function of the cell membrane besides protective covering.

    <p>Regulates the movement of substances in and out of the cell.</p> Signup and view all the answers

    Match the following basic cell structures with their functions:

    <p>Cytoplasm = Cell organelles are suspended within it Nucleus = Contains genetic material and controls cell activities Cell Membrane = Protects the cell and regulates substance movement Nuclear Envelope/Membrane = Encloses the nucleus and controls passage of materials</p> Signup and view all the answers

    What do cholesterol molecules in the cell membrane do?

    <p>Stiffen and strengthen the cell membrane</p> Signup and view all the answers

    What is the function of the glycocalyx (cell coat)?

    <p>All of the above</p> Signup and view all the answers

    The cytoplasm is filled with a homogenous substance known as cytoplasmic ____.

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

    Mitochondria are considered the 'powerhouse' of the cell.

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

    Match the following organelles with their descriptions:

    <p>Mitochondria = Considered the 'powerhouse' of the cell Ribosomes = Responsible for protein synthesis Endoplasmic Reticulum = System of interconnecting tubules and vesicles</p> Signup and view all the answers

    What is the meaning of 'Histology'?

    <p>Histology is the study of microscopic structures of cells and tissues in plants and animals.</p> Signup and view all the answers

    What are important considerations with regards to the method of studying histology?

    <p>Both a and b</p> Signup and view all the answers

    What is the process of removing intercellular and extracellular water from the tissue?

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

    Fixation is a critical part of tissue processing.

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

    Match the following steps in tissue processing with their descriptions:

    <p>Embedding = Placing the impregnated tissue into a mold Staining = Artificially coloring the tissue Mounting = Applying a cover slip over the stained tissue section Labeling = Permanently attaching the assigned accession/identification code</p> Signup and view all the answers

    What is the function of the eyepiece/ocular of a microscope?

    <p>The eyepiece/ocular is the part of the microscope where one looks to see the specimen under study.</p> Signup and view all the answers

    What is the process of copying genetic information from DNA to RNA called?

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

    DNA leaves the nucleus in a double-stranded form during transcription.

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

    What carries amino acids from the cytoplasm to the ribosome during translation?

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

    A series of three adjacent bases in an mRNA molecule codes for a specific amino acid known as ______.

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

    Match the cell transport process with its description:

    <p>Endocytosis = Transport of substances into the cell from the extracellular space Exocytosis = Transport of substances out of the cell across the cell membrane</p> Signup and view all the answers

    What is the function of Simple Squamous Epithelium?

    <p>Acts as a semipermeable barrier between compartments</p> Signup and view all the answers

    Cartilage and Bone tissues are a special type of dense regular connective tissue. In comparison with dense regular tissue, their cells, called chondrocytes and osteocytes are inside cavities called _______

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

    Which of the following is NOT a type of cartilage?

    <p>Muscular Cartilage</p> Signup and view all the answers

    What is the function of the Periosteum?

    <p>Connective tissue that covers the external surfaces of the bone</p> Signup and view all the answers

    Bone growth in length occurs through both the appositional and longitudinal methods.

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

    What protein is responsible for the elasticity of elastic fibers?

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

    Which pancreatic enzyme is able to hydrolyze elastin?

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

    Elastic fibers contain two unique amino acids: Desmosine and __________.

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

    Collagen fibers have tensile strength and are flexible but inelastic.

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

    Match the fiber with its primary protein component:

    <p>Collagen fibers = COLLAGEN (Type I) Elastic fibers = ELASTIN Reticular fibers = COLLAGEN (Type 3)</p> Signup and view all the answers

    What are the characteristics of Connective Tissue?

    <p>Abundance of extracellular material and few cells</p> Signup and view all the answers

    What is the function of Connective Tissue Proper?

    <p>Envelops muscles, binds body parts together, forms stroma of organs, site of substance exchange, and provides body defenses.</p> Signup and view all the answers

    Which type of fibers are primarily responsible for the supportive function of connective tissue? Collagen fibers, Elastic fibers, and _______ fibers.

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

    Elastic fibers are composed of central core of Elastin surrounded by fibrillin microfibrils.

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

    What are the main structural constituents of ground substances in Connective Tissue?

    <p>Hyaluronic acid</p> Signup and view all the answers

    Define bone remodeling.

    <p>Bone remodeling refers to the process of changes in bone shape in response to external or internal factors.</p> Signup and view all the answers

    Which hormone inhibits the bone-forming activity of osteoblasts?

    <p>Parathyroid hormone</p> Signup and view all the answers

    Blood comprises about 8% of a person's body weight.

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

    ______ is the percentage of blood volume accounted for by the Red Blood Cells.

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

    Match the following types of WBCs with their characteristics:

    <p>Neutrophils = Most abundant in circulation, contains pink to rose-violet specific granules Eosinophils = Contain reddish-orange granules, attracted to sites of allergic inflammation Basophils = Contain dark purple to blue-black granules, involved in hypersensitivity reactions Monocytes = Have a blue-gray cytoplasm, involved in phagocytosis Lymphocytes = Blue cytoplasm, principal agents of the body's immune response</p> Signup and view all the answers

    What is the main function of the Golgi complex?

    <p>Receives, processes, sorts, and packages proteins</p> Signup and view all the answers

    Which surface of the Golgi apparatus receives proteins processed by the rough endoplasmic reticulum?

    <p>Convex/cis face</p> Signup and view all the answers

    Lysosomes contain hydrolytic enzymes.

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

    Autophagy refers to the digestion of unneeded or senescent cell ________.

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

    Match the following pigment granules with their descriptions:

    <p>Melanin = Accounts for skin discoloration and present in nerve cells Hemosiderin = Granules found in spleen cells Lipochrome = Yellowish-brown pigments found in muscle cells</p> Signup and view all the answers

    What is the main function of the cytoskeleton?

    <p>Forms the structural framework or skeleton of the cell</p> Signup and view all the answers

    What is the function of microfilaments in the cell?

    <p>Involved in cell movement</p> Signup and view all the answers

    What are the two main components of the Nucleus?

    <p>Chromatin and Nucleolus</p> Signup and view all the answers

    The nuclear envelope is perforated with nuclear pores for exchange of substances between the cytoplasm and the nucleus.

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

    What is the main function of proteins synthesized within the cell?

    <p>Fighting disease, building tissue, Enzymes for digestion and chemical reactions</p> Signup and view all the answers

    Study Notes

    Microscope Structure

    • The microscope contains a lens that can magnify 10X
    • The draw tube holds the eyepiece/ocular
    • The body tube holds the dust shield and the revolving nosepiece

    Functions of Microscope Parts

    • Dust shield: protects the objective lens from dust and dirt
    • Revolving nosepiece: holds the objective lens
    • Objectives:
      • Scanning Objective: usually marked 4X, used to see the general outline of the specimen
      • Low Power Objective (LPO): usually marked 10X, used to view structures in a larger perspective
      • High Power Objective (HPO): usually marked 40X, used to view structures in a more detailed perspective
      • Oil Immersion Objective (OIO): usually marked 100X, used to view structures using oil as a medium
    • Stage: part of the microscope where the glass slide is placed
    • Stage clip: holds and secures the slide
    • Mechanical adjustment knob: moves the stage/slide from left to right and from top to bottom
    • Coarse Adjustment Knob: rapidly raises or lowers the stage/objective to initially bring the specimen into focus
    • Fine Adjustment Knob: used for more precise focusing
    • Iris diaphragm: regulates the amount of light entering the stage
    • Condenser: concentrates the amount of light entering the stage

    Types of Microscopes

    • Monocular microscope: microscope with only one ocular/eyepiece
    • Binocular microscope: microscope with 2 or more oculars/eyepieces
    • Simple microscope: microscope with only one lens
    • Compound microscope: microscope with 2 or more lenses
    • Light Microscope: source of light is visible light
    • Brightfield microscope: structures are colored, the background is clear or lighter in shade
    • Darkfield microscope: the specimen is unstained (no color), but the background is dark in shade
    • Fluorescence microscope: source of light is ultraviolet (UV) light, used in immunofluorescence/immunodiagnostic tests
    • Electron microscope (EM): source of light is an electron beam, used in the study of viruses

    Total Magnification (TM)

    • TM = MP(E) x MP(O)
    • TM = Total Magnification
    • MP = Magnifying power
    • E = Eyepiece
    • O = Objective

    Caring for Your Microscope

    • Tip 1: Handle with care
    • Tip 2: Keep lenses clear of slides
    • Tip 3: Clean after using immersion oil
    • Tip 4: Cover when not in use
    • Tip 5: Look after the bulb
    • Tip 6: Store in a clean, dry place
    • Tip 7: Only use special lens paper or wipes for cleaning the lenses
    • Tip 8: Keep your User's Manual and wrenches in a safe place
    • Tip 9: Perform an annual maintenance check
    • Tip 10: Have your microscope serviced professionally

    The Cell

    • Basic morphological and functional unit of life
    • Capable of independent existence
    • Different sizes, shapes, and forms due to varied specialized functions
    • The human body is composed of ~100 trillion cells, representing more than 250 cell types

    Levels of Organization

    • Chemical
    • Cell
    • Tissue
    • Organ
    • Organ system
    • Organism

    The Cell Membrane

    • Also known as the plasma membrane, plasmalemma, or unit membrane
    • Functions:
      • Protective covering that delimits the cell from its surroundings
      • Determines which substances can move in and out of the cell and regulates the movement of these substances
      • Provides attachment for the skeleton (cytoskeleton) of the cell
      • Receives and sends out stimuli
      • Provides binding sites and receptors for enzymes and other substances
      • Allows cell-cell recognition
      • Forms specialized junctions with the cell membrane of the adjacent cell

    Phospholipid Molecule

    • 3 main parts:
      • Head: globular, polar, and hydrophilic; consists of glycerol that is conjugated to a nitrogenous compound by a phosphate bridge
      • 2 tails: slender, nonpolar, and hydrophobic; one of the two tails consists of a straight-chain saturated fatty acid, while the other consists of an unsaturated fatty acid

    Cholesterol Molecule

    • Serves to stiffen and strengthen the cell membrane
    • Makes the cell membrane less permeable to water-soluble substances

    Glycocalyx

    • Cell covering made up of glycolipids, glycoproteins, and polysaccharides
    • Contributes to cell-cell recognition, cell-to-cell adhesion, and immunological response

    Unit Membrane

    • Generic term referring to the trilaminar entities or structures that comprise the cell membrane and make up or envelope all other membrane-containing structures within the cell

    Specialized Junctions

    • Occluding junctions: prevent the mixing of membrane proteins between apical and basolateral membranes
    • Adhesive junctions:
      • Zonula adherens: initiates cell-to-cell contact and maintenance of contact
      • Fascia adherens: integrin-containing structure
      • Desmosome: mediates direct cell-to-cell contact
      • Hemidesmosome: facilitates stable adhesion of basal cells
    • Communicating junctions:
      • Gap junctions: channels that physically connect adjacent cells, mediating the rapid exchange of small molecules

    Cytoplasm

    • The homogeneous substance that fills the space bounded externally by the cell membrane and internally by the nuclear envelope and the various formed elements that are embedded in it
    • Site of many important biochemical processes and provides a suitable milieu for the organelles in performing their functions### Introduction to Human Histology
    • This material is prepared by the Faculty of the Department of Medical Laboratory Science, LPU-Batangas College of Allied Medical Professions, solely for the use of students enrolled in Human Histology (MLS 202) for the A.Y. 2022-2023.
    • The scope of histology includes the study of human body cases, integration, structures, tissues, techniques, and organ systems.

    The Birth of Histology

    • Robert Hooke (1635-1703) was an English physicist who discovered the law of elasticity and was the first to use the word "cell" to describe the microscopic cavities in cork.
    • Marcello Malpighi (1628-1694) was an Italian physician and biologist who founded the science of microscopic anatomy.
    • Antonie van Leeuwenhoek (1632-1723) was a Dutch microscopist who first observed bacteria and protozoa.
    • Jan Evangelista Purkinje (1787-1869) was a pioneer Czech experimental physiologist who investigated the fields of histology, embryology, and pharmacology.
    • Robert Brown (1773-1858) was a Scottish botanist who discovered cell nuclei and Brownian motion.
    • Theodor Schwann (1810-1882) was a German physiologist who founded modern histology by defining the cell as the basic unit of animal structure.
    • Rudolf Virchow (1821-1902) was a German pathologist and statesman who pioneered the modern concept of pathological processes by applying the cell theory to explain the effects of disease.
    • Marie-François-Xavier Bichat (1771-1802) was a French anatomist and physiologist who helped found the science of histology through his systematic study of human tissues.
    • August Franz Josef Karl Mayer (1787-1865) was a German anatomist and physiologist who coined the term "histology" in 1819.
    • Rudolf Albert von Kölliker (1817-1905) was a Swiss embryologist and histologist who interpreted tissue structure in terms of cellular elements.

    Histology

    • Histology is derived from the Greek words "histos" (tissue) and "logos" (study).
    • It is essentially microanatomy, dealing with the study of microscopic structures of cells and tissues in plants and animals.
    • Histology is concerned with the study of different cell and tissue types sharing related or similar functions that result in the different functions of the body.
    • It serves as the basic foundation to distinguish physiologic from pathologic changes in cells and tissues.

    Importance of Histology

    • Histology is essential for understanding pathology and is an important component of human biology.
    • It is aligned with anatomy and is central to biological and medical sciences.

    Histology vs. Histopathology

    • Histology is the study of normal tissues and cells, while histopathology is the study of diseased tissues and cells.

    Methods of Study

    • Preparation of tissue or organ suitable for viewing is important, including the type of microscope used.
    • Microtechniques include the different methods used for preparation of histological sections.

    Microtechniques

    • Fresh tissue examination involves spreading of blood film, connective tissue, bone marrow film or smear, etc.
    • Preparation of sections from organs involves cutting small pieces of the organ into very thin slices (4-8µm) called sections using paraffin or freezing methods.

    Tissue Processing

    • Tissue processing includes numbering, fixation, decalcification, dehydration, clearing, impregnation, embedding, section cutting/staining, mounting, and labeling.

    Laboratory Scientists as…

    • They play a crucial role in processing and analyzing tissue samples.

    Microscope

    • A microscope is an optical instrument that uses a lens or a combination of lenses to produce magnified images of small objects.
    • General parts of the compound microscope include optical parts (eyepiece, objective lens, and condenser) and mechanical parts (stage, arm, and base).### Protein Synthesis Within the Cell
    • Step 1: Transcription: copying of genetic information from DNA to RNA, where DNA is too large to leave the nucleus, and RNA is single-stranded and can leave the nucleus.
    • Unzipping of DNA: part of DNA temporarily unzips, and is used as a template to assemble complementary nucleotides into messenger RNA (mRNA).
    • mRNA: goes through the pores of the nucleus with the DNA code and attaches to the ribosome.

    Step 2: Translation

    • Decoding of mRNA: into a protein, where transfer RNA (tRNA) carries amino acids from the cytoplasm to the ribosome.
    • Amino acids: come from the food we eat, broken down into individual amino acids, and rearranged into new proteins according to the needs and directions of our DNA.
    • Codon: a series of three adjacent bases in an mRNA molecule codes for a specific amino acid.
    • tRNA: has 3 nucleotides that are complementary to the codon in mRNA, and each tRNA codes for a different amino acid.

    Protein Synthesis

    • Amino acids: are joined together to make a protein.

    Movement of Materials Across the Cell Membrane

    • Endocytosis: refers to the transport of substances from the extracellular space into the cells, which can be either phagocytosis for solid substances or pinocytosis for liquid substances.
    • Exocytosis: refers to the process of transporting substances inside the cells across the cell membrane and out of the cell, which can occur through either regulated secretion or constitutive secretion.

    Regulated Secretion

    • Occurs in: goblet cells, pancreatic acinar cells, and cells of the salivary glands.
    • Secretory vesicles: are first stored in the apical portion of the cell, where they accumulate and get further dehydrated.
    • Dehydrated secretory vesicles: are only released from the cells when there is a specific signal to do so.

    Constitutive Secretion

    • Occurs in: cells such as fibroblasts and chondroblasts.
    • Secretory products: are continuously released from the cell.

    Epithelial Tissue

    • Functions: depends on its location, including protective covering, secretion, absorption, sense of taste and smell, excretion, and production of sex cells.
    • Characteristics: highly cellular, avascular, and exhibits polarity.
    • Embryonic origin: covers the external surfaces of the body, lines the epithelium of digestive tract, heart, blood, lymphatic vessels, urinary system, and male and female reproductive system.

    Basal Lamina

    • Composition: mainly type IV collagen, laminin, entactin, and proteoglycans.
    • Thickness: 20-200 nm.
    • Functions: provides structural support to the overlying epithelium, serves as an impermeable barrier, and limits the contact between epithelial cells and other cell types in the tissue.

    Classification of Epithelial Tissue

    • Covering epithelia: epithelial tissue that covers the body surfaces or lines body cavities.
    • Glandular epithelia: epithelial tissue that produces secretions.
    • Classification based on cell shape and cell layers: simple, stratified, and pseudostratified epithelial tissue.

    Simple Epithelial Tissue

    • Simple squamous epithelium: a single layer of flat, platelike cells that functions as a semipermeable barrier.
    • Simple cuboidal epithelium: a single layer of blocklike cells that regulates ion and water concentration in certain specialized salivary ducts.
    • Simple columnar epithelium: a single layer of tall cells with oval nuclei that are more basal in location.

    Pseudostratified Epithelial Tissue

    • Pseudostratified columnar epithelium: a single layer of cells of variable shape and height, with nuclei at 2 or more levels.

    Stratified Epithelial Tissue

    • Stratified squamous epithelium: composed of several layers, where new cells are formed only in deep layers and superficial old cells have been pushed to the surface.
    • Keratinized type: a multilayered sheet of cells, impervious to water, where superficial cells are squamous, dead, and filled with keratin.

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