General Histology: Epithelial Tissue
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Questions and Answers

What characteristic allows transitional epithelium to function without leakage during stretching?

  • Presence of multiple cell layers
  • Presence of tight junctions between cells (correct)
  • Absence of a basement membrane
  • Ability to change cell shape (correct)

    • Which of the following accurately describes pseudo-stratified epithelium?

  • Is exclusively ciliated
  • Lines the urinary bladder
  • Consists of multiple layers of cells
  • Has nuclei located at varying levels (correct)

    • What distinguishes exocrine glands from endocrine glands?

  • Endocrine glands are involved in digestion
  • Endocrine glands secrete into ducts
  • Only exocrine glands secrete hormones
  • Only exocrine glands have ducts (correct)

    • What type of secretion do mucous glands produce?

    <p>Thick, viscid material</p> Signup and view all the answers

    Which is an example of pseudo-stratified columnar ciliated epithelium?

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

    How do transitional epithelium cells change shape when the urinary bladder is full?

    <p>Become flat and irregular</p> Signup and view all the answers

    Which germ layer is responsible for the development of epithelial tissues such as the lining of the gastrointestinal tract?

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

    What type of gland consists of a single secretory cell?

    <p>Unicellular gland</p> Signup and view all the answers

    Which statement about epithelial tissue is incorrect regarding its structure?

    <p>Epithelial tissues contain a significant amount of intercellular substance.</p> Signup and view all the answers

    What is the primary characteristic that distinguishes simple epithelium from stratified epithelium?

    <p>Simple epithelium consists of only one layer of cells.</p> Signup and view all the answers

    Which structure serves as the lining for organs subjected to tension?

    <p>Transitional epithelium</p> Signup and view all the answers

    Which type of epithelium consists of cells arranged in a single layer but may appear to have multiple layers?

    <p>Pseudo-stratified epithelium</p> Signup and view all the answers

    What is the significance of the high turnover rate of epithelial tissue?

    <p>It allows for rapid healing and regeneration.</p> Signup and view all the answers

    Which epithelial tissue would most likely develop from mesodermal origin?

    <p>Endothelium of blood vessels</p> Signup and view all the answers

    Why are epithelial tissues more susceptible to mutations compared to other tissue types?

    <p>They experience high turnover rates.</p> Signup and view all the answers

    Which classification of epithelium primarily consists of cells arranged in sheets for protection?

    <p>Stratified epithelium</p> Signup and view all the answers

    Which characteristic is true about elastic cartilage compared to hyaline cartilage?

    <p>It is more flexible and elastic.</p> Signup and view all the answers

    Where can fibrocartilage be typically found?

    <p>In intervertebral discs.</p> Signup and view all the answers

    What is the primary structural feature of skeletal muscle tissue?

    <p>It is striated and voluntary.</p> Signup and view all the answers

    What distinguishes smooth muscle tissue from other types of muscle tissue?

    <p>It has tapering, elongated fibers.</p> Signup and view all the answers

    Which statement accurately describes the collagen fibers in fibrocartilage?

    <p>They are arranged in parallel bundles along the direction of stress.</p> Signup and view all the answers

    How does the cytoplasm of muscle cells, known as sarcoplasm, differ from that of typical cells?

    <p>It is rich in myofibrils and proteins.</p> Signup and view all the answers

    What is unique about the arrangement of chondrocytes in fibrocartilage?

    <p>They are arranged in rows between collagen bundles.</p> Signup and view all the answers

    Which muscle type is classified as striated and involuntary?

    <p>Cardiac muscle.</p> Signup and view all the answers

    What is the shape of the nuclei in skeletal muscle fibers?

    <p>Oval and peripheral</p> Signup and view all the answers

    What distinguishes the A band in myofibrillar banding?

    <p>Contains thick myofilaments of myosin</p> Signup and view all the answers

    Where is smooth muscle primarily distributed?

    <p>In hollow viscerae and blood vessels</p> Signup and view all the answers

    Which of the following accurately describes the contraction of smooth muscle?

    <p>Slow, sustained, and resistant to fatigue</p> Signup and view all the answers

    What primarily composes the light band (I band) in muscle fibers?

    <p>Thin myofilaments (actin) only</p> Signup and view all the answers

    What happens to the size of skeletal muscle fibers during periods of disuse?

    <p>Decreases in diameter and length</p> Signup and view all the answers

    What structural unit is formed between successive Z lines in muscle fibers?

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

    Which of the following statements about myofibrils is accurate?

    <p>They contain fundamental units called myofilaments.</p> Signup and view all the answers

    What type of cells primarily line the lumen of arteries in the tunica intima?

    <p>Polygonal endothelial cells</p> Signup and view all the answers

    Which artery type contains 40-60 bands of elastic tissue in its tunica media?

    <p>Elastic arteries</p> Signup and view all the answers

    What is a key characteristic of the internal elastic lamina in muscular arteries?

    <p>It is prominent and appears as a wavy band</p> Signup and view all the answers

    Which component primarily makes up the tunica adventitia of elastic arteries?

    <p>Bundles of collagen fibres</p> Signup and view all the answers

    In terms of thickness, how does the tunica media of muscular arteries compare to their lumen?

    <p>Significantly thicker than the lumen</p> Signup and view all the answers

    Which layer of elastic arteries comprises up to 80% of the total thickness of the aortic wall?

    <p>Tunica Media</p> Signup and view all the answers

    What characterizes the tunica adventitia in muscular arteries compared to elastic arteries?

    <p>It is thinner than the media</p> Signup and view all the answers

    What role do vasa vasorum play in blood vessels?

    <p>They supply blood to the outer layers of larger arteries</p> Signup and view all the answers

    What is characteristic of the cytoplasm of mucous-secreting cells?

    <p>It appears vacuolated and basophilic.</p> Signup and view all the answers

    Which gland type is characterized by the total disintegration of secretory cells to release their contents?

    <p>Holocrine gland</p> Signup and view all the answers

    What distinguishes the histological appearance of serous secreting cells?

    <p>Triangular shape with basophilic apical cytoplasm.</p> Signup and view all the answers

    Which gland primarily produces a clear, watery fluid containing enzymes?

    <p>Parotid gland</p> Signup and view all the answers

    What feature identifies mixed glands in terms of secretory structure?

    <p>Distinct crescent-shaped serous units.</p> Signup and view all the answers

    Which type of gland secretes material by discharging part of the cell?

    <p>Apocrine gland</p> Signup and view all the answers

    What is a defining characteristic of merocrine glands?

    <p>Discharge of secretory material without loss of cell parts.</p> Signup and view all the answers

    What defines the shape of tubular exocrine glands?

    <p>Hollow cylinder shape.</p> Signup and view all the answers

    Study Notes

    General Histology Contents

    • General Histology: page 1
    • Histology of Epithelial Tissue: page 1
    • Histology of Connective Tissue: page 15
    • Histology of Bone and Cartilage: page 23
    • Histology of Muscular Tissue: page 30
    • Histology of Blood Vessel: page 35
    • Histology of Nervous Tissue: page 43

    Histology of Epithelial Tissue

    • Body is composed of cells, intercellular substances and tissue fluid
    • Body develops from 3 germ layers: Ectoderm, Mesoderm, and Endoderm
    • These 3 germ layers formed the 4 primary tissues: epithelial, connective, muscular, and nervous tissue
    • Epithelial tissue is continuous layer(s) of cells with little to no intercellular substance
    • Epithelial cells are arranged in sheets or masses
    • Epithelial cells rest on basement membrane which is avascular and alymphatic
    • Epithelial tissue develops from ectoderm, endoderm, or mesoderm
    • Epithelium develops from ectoderm: skin, mouth, anus
    • Epithelium develops from endoderm: lining of gastrointestinal tract, respiratory tract, glands
    • Epithelium develops from mesoderm: lining of blood vessels, lymphatic vessels, coelomic cavity (e.g., pleura)
    • Epithelia have the highest turnover rate of the four basic tissue types
    • Turnover rate varies depending on location and function
    • Skin epithelium turns over every 30 days
    • Colonic mucosal epithelium turns over every week

    Simple Epithelium

    • Consists of only one layer of cells, with all cells touching the basement membrane
    • Divided in three types based on cell shape
    • Simple squamous
    • Simple cuboidal
    • Simple columnar

    Simple Squamous Epithelium

    • Composed of one layer of flat or squamous cells resting on the basement membrane
    • Cells are irregular in outline, similar to platform plates
    • Nucleus is single, round, and centrally positioned

    Simple Cuboidal Epithelium

    • Composed of a single layer of cubic or square shaped cells resting on the basement membrane
    • Cells appear hexagonal
    • Nucleus is single, round, and centrally positioned
    • Function includes protection, secretion, and absorption

    Simple Columnar Epithelium

    • Composed of a single layer of tall cells resting on the basement membrane
    • Cells appear hexagonal
    • Nucleus is single, oval, and basally positioned
    • Functions include protection, lining, and secretion
    • It lines gastrointestinal tract (stomach to upper half of anal canal), excretory ducts of kidney, and uterine tube

    Stratified Epithelium

    • More than one cell layer
    • Only the basal layer touches the basement membrane
    • Classified into 4 types
    • Stratified squamous
    • Stratified cuboidal
    • Stratified columnar
    • Transitional epithelium

    Stratified Squamous Epithelium

    • Consists of multiple layers of cells, resulting in the exposed surface of the epithelium being squamous
    • Divided into keratinized and nonkeratinized based on presence or absence of keratin
    • Keratinized examples: skin
    • Nonkeratinized examples: tongue, esophagus, vagina, and palatine tonsil.

    Stratified Cuboidal Epithelium

    • Superficial layer of cells is cuboidal in shape
    • Function includes protection and secretion
    • Found in ducts of sweat glands, multilayered primary ovarian follicles

    Stratified Columnar Epithelium

    • Superficial layer of cells is columnar
    • Function is protection
    • Found in conjunctiva and cavernous portion of male urethra

    Transitional Epithelium

    • The cells change shape depending on the degree of distension of the organ
    • Lines hollow organs (e.g., urinary bladder) that are prone to stretching
    • No obvious basement membrane
    • There is a superficial cell layer appearing as umbrella shaped, with nuclei that are single and central
    • In relaxed state, there are multiple layers of pear-shaped cells
    • In stretched state, shapes flatten and layers decrease to 2 or 3
    • Lines organs subjected to tension, such as urinary bladder, ureter, urethra near bladder, covering calyces, and pelvis of the kidney

    Pseudostratified Epithelium

    • One layer of cells but appears multilayered because nuclei are at different levels
    • All cells touch the basement membrane but not all reach the surface
    • Two types
    • Pseudostratified columnar ciliated
    • In respiratory tract
    • Pseudostratified columnar nonciliated
    • Lining the penile urethra

    Histology of Glandular Epithelium

    • Glandular tissue is specialized for secretory functions
    • Two types of glands
    • Exocrine
    • Endocrine

    Classification of Exocrine Glands

    • Based on Cell Number/Nature of Secretion
      • Unicellular*: One cell (e.g., goblet cell)
      • Multicellular*: More than one cell
    • Mucous—secrete thick, viscid material called mucin (e.g., sublingual salivary gland)
    • Serous—secrete clear, watery fluid with enzymes (e.g., parotid gland)
    • Mixed—both mucous and serous secretions (e.g., submandibular salivary gland)

    According to Mode of Secretion

      • Merocrine (eccrine)*: Secrete through exocytosis, no loss of cellular components (e.g., sweat glands)
      • Apocrine*: Secretion and part of the cell are discharged. (e.g., apocrine sweat glands)
      • Holocrine*: Entire secretory cell disintegrates to release secretion. (e.g., sebaceous glands)

    Classification of Glands by Duct System

      • Simple glands*: Single, unbranched duct. (e.g., intestinal glands, gastric glands)
      • Compound glands*: Branched duct. (e.g., salivary, mammary glands, pancreas)
          • Tubular*: hollow structure
          • Alveolar (acinar)*: rounded structure
          • Tubuloalveolar*: combination of both

    Histology of Endocrine Glands

    • Secretion is released into the bloodstream
    • No ducts
    • Cells are arranged in cords or plates
    • e.g. Suprarenal, parathyroid gland
    • Some glands form sacs (follicles)
    • e.g., Thyroid follicles, ovarian follicles

    Histology of Connective Tissue

    • Supporting and connecting tissue
    • Derived from embryonic mesenchyme
    • Types
    • Embryonic
    • Mesenchyme: gives rise to other connective tissues (except neuroglia)
    • Mucous: found in the umbilical cord
    • Adult
    • Areolar (loose): widespread throughout body
    • Fibrous (dense): tendons, ligaments
    • Adipose (fat): storage, insulation (adipocytes)
    • Cartilage: support, flexibility
    • Bone: support, structure, strength
    • Blood (specialized): transport, immunity
    • Reticular: stroma (e.g. lymphatic organs)

    Cells of Connective Tissue

    • Fibroblasts: secrete fibers and ground substance
    • Macrophages: phagocytose foreign materials
    • Plasma cells: produce antibodies
    • Mast cells: release histamine and heparin (involved in allergic reactions)
    • Fat cells (adipocytes): store fat for energy
    • Leukocytes: immune cell types

    Intercellular Substance

    • Solid ground substance (amorphous): hyaluronic acid, proteoglycans
    • Fibers: collagen (strength), elastic (stretch), reticular (support)

    Histology of Bone and Cartilage

    • Bone:
    • Specialized type of connective tissue
    • Composed of cells, fibers, and matrix
    • Bone cells (osteoblasts, osteocytes, osteoclasts)
    • Matrix (35% organic, 65% inorganic) organic component is collagenous fibrils
    • Types (e.g., compact, spongy/cancellous)
    • Cartilage:
    • Specialized type of connective tissue providing support and flexibility
    • Composed of cells (chondrocytes) and matrix
    • Types (e.g., hyaline, elastic, fibrocartilage)

    Histology of Muscular Tissue

    • Three types based on structure and function
    • Smooth: nonstriated, involuntary, found in internal organs
    • Cardiac: striated, involuntary, found in the heart
    • Skeletal: striated, voluntary, found attached to bones
    • Detailed notes:* further breakdowns of each topic are found within the pages of text.

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    General Histology PDF

    Description

    Explore the key concepts and structures of epithelial tissue in the context of general histology. This quiz covers the development, types, and characteristics of epithelial cells as part of the four primary tissue types in the body. Test your knowledge on how these tissues are formed from the three germ layers.

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