Epithelial Tissue Characteristics
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Questions and Answers

What is the primary function of covering epithelia?

  • Secretion of hormones
  • Transmission of nerve impulses
  • Protection of underlying tissues (correct)
  • Contraction and movement
  • What is unique about the structure of epithelial tissue?

  • It is composed of loose connective tissue
  • It has closely aggregated polyhedral cells (correct)
  • It has a large number of blood vessels
  • It has a large amount of extracellular substance
  • What is the function of glandular epithelia?

  • To absorb nutrients
  • To provide sensation
  • To secrete hormones (correct)
  • To protect underlying tissues
  • What is the purpose of the basal lamina?

    <p>To separate epithelial cells from connective tissue</p> Signup and view all the answers

    What is the main component of the lamina densa?

    <p>Collagen type IV</p> Signup and view all the answers

    What connects integrins on the basal surface of epithelial cells to the type IV collagen network?

    <p>Laminin 5</p> Signup and view all the answers

    What is the function of neuroepithelial cells?

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

    What is unique about the nutrition of epithelial cells?

    <p>They receive nutrition from connective tissue</p> Signup and view all the answers

    What type of collagen is found in anchoring fibrils that link the basement membrane to the interstitial matrix?

    <p>Type VII collagen</p> Signup and view all the answers

    Which of the following proteins do integrins on the fibroblast cell surface interact with?

    <p>Type I collagen</p> Signup and view all the answers

    What is the name of the surface of epithelia that rests on the basal lamina?

    <p>Basal surface</p> Signup and view all the answers

    What is the classification of epithelia based on the number of layers?

    <p>Simple, stratified, and pseudostratified</p> Signup and view all the answers

    Which of the following is NOT a classification of epithelia based on the shape of cells?

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

    What is the name of the type of epithelium that is found in the urinary tract?

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

    What type of epithelium is found in the respiratory passages?

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

    What is the main function of tight junctions in epithelial cells?

    <p>To prevent the flow of substances between epithelial cells</p> Signup and view all the answers

    What is the function of microvilli in epithelial cells?

    <p>To increase the surface area for absorption</p> Signup and view all the answers

    What is the function of gap junctions in epithelial cells?

    <p>To facilitate the movement of small molecules between cells</p> Signup and view all the answers

    What type of glandular epithelium is found in the stomach?

    <p>Goblet cell</p> Signup and view all the answers

    What is the function of cilia in epithelial cells?

    <p>To remove material over epithelium</p> Signup and view all the answers

    What is the function of the glycocalyx in epithelial cells?

    <p>To provide protection and antigenic character to the cell</p> Signup and view all the answers

    What is the function of basal striations in epithelial cells?

    <p>To provide structural support to the cell</p> Signup and view all the answers

    What is the characteristic of holocrine glands?

    <p>Secretory product is shed with whole cell</p> Signup and view all the answers

    What is the characteristic of apocrine glands?

    <p>Secretory product is discharged with apical part of cytoplasm</p> Signup and view all the answers

    Study Notes

    Epithelial Tissue

    • Covers body surfaces and lines body cavities
    • Made up of special cells that enable it to fulfill many functions:
      • Protection
      • Secretion
      • Excretion
    • Found in various parts of the body, including:
      • Respiratory passages
      • Oral cavity
      • Skin
      • Digestive tract
      • Heart and blood vessels
      • Peritoneum
      • Pericardium
      • Urinary tracts
      • Glands
      • Lymph vessels

    Characteristics of Epithelial Tissue

    • Composed of closely aggregated polyhedral cells
    • Almost no or no extracellular substance
    • Epithelial cells are separated from connective tissue by the basal lamina
    • No blood vessels; nutrition is from connective tissue

    Functions of Epithelia

    • Covering epithelia:
      • Covering of surfaces and lining of cavities
      • Protection of covered tissue
      • Absorption (intestines, proximal tubules of kidney)
    • Glandular epithelia:
      • Secretion (exocrine glands)
    • Neuroepithelial cells:
      • Sensation (olfactory epithelium, taste buds)

    Basal Lamina

    • Selective barrier between connective tissue and epithelium
    • Adhesion of connective tissue and epithelium
    • Supports cells
    • Components of basal lamina:
      • Lamina lucida (rara)
      • Lamina densa
      • Reticular lamina

    Polarity of Epithelia

    • Apical surface
    • Basal surface: rests on basal lamina
    • Lateral surface

    Classification of Epithelia

    • According to number of layers:
      • Simple
      • Stratified
      • Pseudostratified
    • According to shape of cells:
      • Squamous
      • Cuboidal
      • Columnar

    Simple Epithelia

    • Simple squamous epithelium:
      • Endothelium, mesothelium, air sacs of the lungs (alveoli)
    • Simple cuboidal epithelium:
      • Proximal and distal renal tubules
    • Simple columnar epithelium:
      • Stomach, small and large intestine, oviduct

    Stratified Epithelia

    • Stratified squamous epithelium:
      • Keratinized (skin)
      • Non-keratinized (oral cavity, vagina)
    • Stratified cuboidal epithelium:
      • None mentioned
    • Stratified columnar epithelium:
      • None mentioned
    • Transitional epithelium:
      • Urinary bladder, ureter

    Intercellular Junctions

    • Tight junction (zonula occludens)
    • Desmosome (macula adhaerens)
    • Hemidesmosome
    • Gap junction (nexus)

    Epithelial Surfaces Modifications

    • Microvilli:
      • Extensions of cytoplasm
      • Increase surface area for absorption
    • Cilia:
      • Long projections
      • Motile
      • Enable removal of material over epithelium
    • Stereocilia:
      • Long microvilli (in epididymis and ductus deferens)
    • Flagella:
      • Similar structure to cilia

    Glandular Epithelia

    • Function: secretion of products used in other parts of the organism
    • Types of exocrine glands:
      • Holocrine
      • Apocrine
      • Merocrine
    • Unicellular glands:
      • Mucous secretion
    • Multicellular glands:
      • Branched
      • Compound
      • Tubule
      • Acini
      • Tubuloacini

    Sensory Epithelia

    • Enables sensation (olfactory epithelium, taste buds)

    Nutrition of Epithelia

    • No blood vessels in epithelia
    • Nutrients and precursors of products diffuse from connective tissue across the basal lamina to epithelial cells

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    Related Documents

    Epithelial Tissue PDF

    Description

    This quiz covers the characteristics and functions of epithelial tissue, including its role in protection, secretion, and excretion, as well as its presence in various body systems and organs.

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