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Anatomy & Physiology: Tissue Structure and Function

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  • What are the four basic tissue types in the human body?

    The four basic tissue types are epithelial, connective, muscle, and nervous tissue.

  • What is epithelial tissue and its main functions?

    Epithelial tissue is a sheet of cells covering body surfaces or cavities. Its main functions include protection, absorption, filtration, excretion, secretion, and sensory reception.

  • Name the five special characteristics of epithelial tissue.

    1. Polarity (apical and basal surfaces)
    2. Specialized contacts (tight junctions, desmosomes)
    3. Supported by connective tissue
    4. Avascular but innervated
    5. Regeneration

  • What is the difference between the apical and basal surfaces of epithelial cells?

    The apical surface is the upper free side exposed to the body surface or cavity, often with microvilli. The basal surface is the lower attached side facing inward, attached to the basal lamina.

  • How are epithelial tissues classified by layers and cell shape?

    By layers: Simple (one layer), Stratified (multiple layers).
    By shape: Squamous (flat), Cuboidal (cube-shaped), Columnar (tall column-like).

  • What is the function and location of simple squamous epithelium?

    Allows rapid diffusion and filtration. Found in kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, and lymphatic vessels.

  • Describe simple cuboidal epithelium and its function.

    Single layer of cube-like cells with large, spherical nuclei. Functions in secretion and absorption. Located in kidney tubules and ducts of small glands.

  • What are the features and functions of simple columnar epithelium?

    Single layer of tall cells, some with microvilli or cilia, may contain goblet cells. Functions in absorption and secretion of mucus and enzymes. Found in digestive tract and uterine tubes.

  • What is pseudostratified columnar epithelium and where is it found?

    Single layer of cells of varying heights that appears stratified. Often ciliated and contains goblet cells. Found in upper respiratory tract and ducts of large glands.

  • What distinguishes stratified squamous epithelium?

    Multiple layers with flat cells at the surface. Protects underlying tissues in areas of high wear and tear like skin and mouth. Can be keratinized or nonkeratinized.

  • What is transitional epithelium and its function?

    Resembles both stratified squamous and cuboidal; basal cells are cuboidal or columnar. Allows stretching to accommodate urine volume changes. Found in urinary bladder, ureters, and urethra.

  • How are glands classified based on product release and cell number?

    By product release: Endocrine (ductless, secrete hormones internally), Exocrine (secrete onto body surfaces or cavities via ducts).
    By cell number: Unicellular (e.g., goblet cells), Multicellular (e.g., salivary glands).

  • What are the three modes of secretion in multicellular exocrine glands?

    Merocrine: secretion by exocytosis.
    Holocrine: entire cell ruptures to release secretion.
    Apocrine: apex of cell pinches off (controversial in humans).

  • What are the main components of connective tissue?

    Connective tissue consists of cells, fibers (collagen, elastic, reticular), and ground substance forming the extracellular matrix.

  • What are the three types of connective tissue fibers and their functions?

    Collagen fibers: strongest, provide tensile strength.
    Elastic fibers: allow stretch and recoil.
    Reticular fibers: fine, branched fibers forming supportive networks.

  • What is the difference between 'blast' and 'cyte' cells in connective tissue?

    Blast cells are immature, actively secreting matrix components.
    Cyte cells are mature, maintain the matrix.

  • Name the four main classes of connective tissue.

    Connective tissue proper, cartilage, bone, and blood.

  • What are the characteristics and functions of areolar connective tissue?

    Gel-like matrix with all three fiber types and various cells. Wraps and cushions organs, holds fluids, and plays a role in inflammation. Widely distributed under epithelia.

  • Describe adipose tissue and its functions.

    Closely packed adipocytes with scant matrix. Stores energy, insulates, cushions organs, and is richly vascularized. Found under skin and around organs.

  • What are the three types of cartilage and their features?

    Hyaline cartilage: most abundant, glassy appearance.
    Elastic cartilage: more elastic fibers, found in ears.
    Fibrocartilage: strong, found in intervertebral discs.

  • What distinguishes bone tissue from cartilage?

    Bone has a hard matrix with inorganic calcium salts and collagen, is highly vascularized, supports and protects body structures, and stores fat and synthesizes blood cells.

  • What are the three types of muscle tissue and their characteristics?

    Skeletal muscle: voluntary, striated, multinucleated.
    Cardiac muscle: involuntary, striated, branched, with intercalated discs.
    Smooth muscle: involuntary, nonstriated, spindle-shaped cells.

  • What are the two main cell types in nervous tissue?

    Neurons: generate and conduct nerve impulses.
    Supporting cells: insulate, protect, and support neurons.

  • What are the three types of covering and lining membranes?

    Cutaneous membranes: skin, dry membrane.
    Mucous membranes: line body cavities open to exterior, moist.
    Serous membranes: line closed ventral cavities, moist with serous fluid.

  • What are the two major ways tissue repair occurs?

    Regeneration: replacement with same tissue type, restoring function.
    Fibrosis: replacement with connective tissue, function lost.

  • Which tissues have high, moderate, and low regenerative capacities?

    High: epithelial, bone, areolar, dense irregular, blood-forming tissues.
    Moderate: smooth muscle, dense regular connective tissue.
    Low: cardiac muscle, nervous tissue of brain and spinal cord.