Tissues

Subdecks (1)

Cards (97)

  • Tissues
    Functionally related groups of cells that work together
  • Types of tissues
    • Epithelial
    • Connective
    • Muscle
    • Nervous
  • Epithelial tissue

    • Covers a body surface or lines a body cavity
    • Forms most glands
    • Functions: Protection, Absorption & Secretion, Filtration, Forms slippery surfaces
  • Epithelial tissue characteristics
    • Cellularity - cells in close contact with little intercellular space
    • Specialized contacts - junctions for attachment and communication
    • Polarity - apical and basal surface
    • Support by connective tissue - contributes to basement membrane
    • Avascular - nutrients must diffuse
    • Innervated
    • High capacity for regeneration
  • Lateral surface features of epithelial cells
    • Adhesion proteins link plasma membranes of adjacent cells
    • Special cell junctions: Tight junctions, Gap junctions, Desmosomes
  • Tight junctions
    Close off intercellular space, prevent molecules passing between cells
  • Desmosomes
    Two disc-like plaques connected across intercellular space, proteins interdigitate into extracellular space, intermediate filaments insert into plaques
  • Gap junctions
    Passageway between two adjacent cells, let small molecules move directly between neighboring cells
  • Simple epithelium
    One layer of cells
  • Stratified epithelium
    More than one layer of cells
  • Squamous epithelium
    Cells wider than tall, plate or "scale" like
  • Cuboidal epithelium

    Cells as wide as tall, cube-like
  • Columnar epithelium

    Cells taller than wide, column-like
  • Pseudostratified columnar epithelium
    All cells originate at basement membrane, only tall cells reach apical surface, nuclei at varying heights
  • Simple squamous epithelium
    • Single layer of flat cells with disc-shaped nuclei
    • Functions: Passage of materials by diffusion and filtration, Secretes lubricating substances
    • Locations: Renal corpuscles, Alveoli of lungs, Lining of heart, blood and lymphatic vessels, Lining of ventral body cavity
  • Simple cuboidal epithelium
    • Single layer of cube-like cells with large, spherical central nuclei
    • Functions: Secretion and absorption
    • Locations: Kidney tubules, Secretory portions of small glands, Ovary & thyroid follicles
  • Simple columnar epithelium
    • Single layer of column-shaped (rectangular) cells with oval nuclei
    • Some bear cilia at apical surface, May contain goblet cells
    • Functions: Absorption, Secretion of mucus, enzymes, and other substances, Ciliated type propels mucus or reproductive cells
    • Locations: Non-ciliated - Lines digestive tract, gallbladder, ducts of some glands, Ciliated - Lines small bronchi, uterine tubes, uterus
  • Pseudostratified columnar epithelium
    • All cells originate at basement membrane, only tall cells reach apical surface, may contain goblet cells and bear cilia, nuclei at varying heights
    • Functions: Secretion of mucus, propulsion of mucus by cilia
    • Locations: Non-ciliated - Ducts of male reproductive tubes, Ducts of large glands, Ciliated - Lines trachea and most of upper respiratory tract
  • Stratified epithelia
    • Contain two or more layers of cells, Regenerate from below, Major role is protection
  • Stratified squamous epithelium

    • Many layers of cells, squamous in shape at apical layer, deeper layers cuboidal or columnar
    • Keratinized - Surface cells dead and full of keratin, Non-keratinized - Moist lining of body openings
    • Functions: Protects underlying tissues in areas subject to abrasion
    • Locations: Keratinized - Epidermis, Non-keratinized - Esophagus, mouth, vagina
  • Glandular epithelium
    Ducts carry products of exocrine glands to epithelial surface, May be unicellular or multicellular
  • Goblet cells
    • Produce mucin, Mucin + water = mucus, Protects and lubricates many internal body surfaces
  • Multicellular exocrine glands
    Classified by structure of duct and mode/type of secretion (merocrine, apocrine, holocrine)
  • Connective tissue

    Most diverse and abundant tissue, Main classes: Connective tissue proper, Blood, Cartilage, Bone, Components: Cells, Matrix (protein fibers, ground substance), Common embryonic origin - mesenchyme
  • Classes of connective tissue
    • Loose connective tissue
    • Dense connective tissue
    • Adipose tissue
    • Cartilage
    • Bone
    • Blood
  • Skeletal muscle tissue

    • Long, cylindrical cells, Multinucleate, Obvious striations
    • Functions: Voluntary movement, Manipulation of environment, Facial expression
    • Locations: Skeletal muscles attached to bones
  • Smooth muscle tissue
    • Spindle-shaped cells with central nuclei, Arranged in sheets, No striations
    • Functions: Propels substances along internal passageways, Involuntary control
    • Locations: Mostly walls of hollow organs
  • Cardiac muscle tissue
    • Branching cells, Uni-nucleate, Intercalated discs
    • Function: Contracts to propel blood into circulatory system
    • Location: Walls of heart
  • Nervous tissue
    Transmits electrical signals from sensory receptors to effectors, Main components: Brain, spinal cord, nerves, Contains neurons and supporting neuroglial cells
  • Rectum
    The last part of the colon that stores feces until defecation
  • Anal sphincter
    Controls defecation
  • Appendix
    • A vestigial attachment of the cecum
    • Located between the small and large intestine
  • Summary of Digestive Enzymes
    • Salivary amylase
    • Pepsin (protease)
    • Trypsin (protease)
    • Lipase
    • Nuclease
  • Salivary amylase
    Breaks down starch
  • Pepsin
    Breaks down proteins
  • Trypsin
    Breaks down polypeptides into peptides
  • Lipase
    Breaks down fats into fatty acids and glycerol
  • Nuclease
    Breaks down nucleic acids into nucleotides
  • pH
    Optimal pH for each enzyme
  • The presence of large numbers of mitochondria in the cells lining the small intestine allows them to absorb nutrients