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Anatomy & Physiology: Tissue Level of Organization

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Termini in questo insieme (36)

  • What is a tissue?
    Tissue is a group of specialized cells and cell products that perform one or more specific functions.
  • What are the four basic types of tissue?
    Epithelial, connective, muscle, and nervous tissues.
  • What are the main functions of epithelial tissue?
    Covers exposed surfaces, lines internal passageways, forms glands, provides physical protection, controls permeability, sensation, and specialized secretions.
  • What are the key characteristics of epithelial tissue?
    Polarity, cellularity, attachment to basement membrane, avascularity, and regeneration.
  • What is the function of microvilli in epithelial cells?
    Microvilli increase surface area for absorption and secretion, especially in digestive tract regions.
  • What is the role of cilia in epithelial tissue?
    Motile cilia move fluids or secretions over epithelial surfaces, such as mucus in the respiratory tract.
  • Name the two main types of intercellular connections in epithelial tissue.
    Cell adhesion molecules (CAMs) and cell junctions.
  • What are cell adhesion molecules (CAMs)?
    Transmembrane proteins that attach opposing plasma membranes and connect cells to extracellular materials.
  • List the three most common types of cell junctions.
    Gap junctions, tight junctions, and desmosomes.
  • What is the function of gap junctions?
    Hold cells together via connexons and allow small molecules and ions to pass between cells.
  • How do tight junctions function?
    They tightly bind plasma membranes to prevent water and solutes from passing between cells.
  • What is the function of desmosomes?
    Link opposing plasma membranes via CAMs and proteoglycans, connecting to the cytoskeleton to stabilize cell shape.
  • What are hemidesmosomes?
    Structures that attach epithelial cells to the basement membrane, resembling half of a desmosome.
  • How are epithelia classified by cell shape?
    Squamous (thin, flat), cuboidal (box-like), and columnar (tall, slender rectangles).
  • What are the two classifications of epithelia by layers?
    Simple (one cell layer) and stratified (multiple cell layers).
  • Where is simple squamous epithelium found and what is its function?
    Found in protected regions like alveoli; functions in absorption and diffusion.
  • What is the difference between keratinized and nonkeratinized stratified squamous epithelium?
    Keratinized has layers packed with keratin for toughness and water resistance; nonkeratinized resists abrasion but must stay moist.
  • What is transitional epithelium?
    A stratified epithelium that appears cuboidal when relaxed and squamous when stretched; found in the urinary bladder.
  • What distinguishes pseudostratified columnar epithelium?
    Appears layered but all cells contact the basement membrane; often ciliated to move mucus.
  • What are the two types of glandular epithelia?
    Endocrine glands (ductless, secrete hormones into blood) and exocrine glands (secrete onto epithelial surfaces or ducts).
  • What are the three basic components of connective tissue?
    Specialized cells, extracellular protein fibers, and ground substance (fluid).
  • What are the three general categories of connective tissue?
    Connective tissue proper, fluid connective tissues, and supporting connective tissues.
  • What are fibroblasts and their function?
    Most abundant fixed cells in connective tissue proper; secrete hyaluronan and protein subunits for collagen, reticular, and elastic fibers.
  • What are the main fiber types in connective tissue proper?
    Collagen fibers (strong, flexible), reticular fibers (branching, flexible framework), and elastic fibers (stretch and recoil).
  • What is the function of ground substance in connective tissue proper?
    A viscous, clear substance that fills spaces between cells and fibers, slowing pathogen movement.
  • What are the main functions of loose connective tissue?
    Fills spaces, cushions organs, supports epithelia, and stabilizes cells.
  • What distinguishes dense regular from dense irregular connective tissue?
    Dense regular has parallel collagen fibers aligned with force direction; dense irregular has interwoven fibers for strength in multiple directions.
  • What are the characteristics of cartilage as a supporting connective tissue?
    Firm gel matrix with chondroitin sulfates; avascular; cells called chondrocytes in lacunae; limited repair ability.
  • What are the three types of cartilage?
    Hyaline (tough, flexible), elastic (supportive, very flexible), and fibrocartilage (durable, shock absorbing).
  • What makes bone matrix strong and somewhat flexible?
    Calcified calcium salts provide hardness; collagen fibers provide strength and flexibility.
  • What are the three types of muscle tissue?
    Skeletal (striated voluntary), cardiac (striated involuntary), and smooth (nonstriated involuntary).
  • What are the main features of skeletal muscle tissue?
    Long, multinucleate fibers; striated; voluntary contraction; limited repair via myosatellite cells.
  • What are intercalated discs in cardiac muscle?
    Specialized connections containing desmosomes, proteoglycans, and gap junctions that coordinate contractions.
  • What distinguishes smooth muscle tissue?
    Nonstriated, involuntary muscle found in walls of blood vessels and hollow organs; capable of regeneration.
  • What are the two main cell types in nervous tissue?
    Neurons (communicative cells) and neuroglia (supporting cells).
  • What are the main components of a neuron?
    Cell body (with nucleus), dendrites (receive information), and axon (conducts electrical signals).