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• There are four levels of organization: cells, tissues, organs, and organ systems.
• Bodies of vertebrates are composed of different cell types, with humans having 210 cell types.
• Tissues

  Groups of cells that are similar in structure and function
• Three fundamental embryonic tissues (germ layers)


  • Endoderm(lining of digestive/resp.)
  • Mesoderm(muscle,skeleton)
  • Ectoderm(skin, sense organs)
• Four primary tissues in adult vertebrates


  • Epithelial
  • Connective
  • Muscle
  • Nerve
• Organs

  Combinations of different tissues that form a structural and functional unit, outermost layer:skin and accessories.
• Organ systems

  Groups of organs that cooperate to perform the major activities of the body
• The general body plan of all vertebrates is essentially a tube within a tube: the inner tube is the digestive tract, and the outer tube is the main vertebrate body.
• Two main body cavities

  • Dorsal body cavity
  • Ventral body cavity
• Epithelial membrane (epithelium)


  Covers every surface of the vertebrate body
• Epithelial tissues attach to underlying connective tissues by a fibrous membrane., generative power
• Two general classes of epithelial tissues


  • Simple
  • Stratified
• Subtypes of epithelial cells


  • Squamous
  • Cuboidal
  • Columnar
• Types of simple epithelium

  • Simple squamous
  • Simple cuboidal
  • Simple columnar
• Glands

  Form from invaginated epithelia
• Types of glands

  • Exocrine-connected to epithelium by duct(salivary)
  • Endocrine- ductless(hormones)
• Stratified epithelium


  are named according to the feature of their apical cell layer
• Epidermis is a stratified squamous epithelium.
• Neurons

  Cells that include the cell body(nucleus), dendrites(towards), and axon(away)
• Neuroglia


  Support and insulate neurons and eliminate foreign materials
• Divisions of the nervous system


  • Central nervous system (CNS)
  • Peripheral nervous system (PNS)
• Three basic types of neurons


  • Sensory
  • Motor
  • Interneuron
• Connective tissues


  Derive from embryonic mesoderm and have abundant extracellular material (matrix)
• Two major classes of connective tissues


  • Connective tissue proper(loose/dense)
  • Special connective tissue(cartilage, blood, bone)
• Loose connective tissue


  Cells scattered within a matrix that contains a large amount of ground substance
• Dense connective tissue


  Contains less ground substance than loose connective tissue
• Cartilage

  Firm and flexible tissue that does not stretch, with great tensile strength
• Bone

  Osteocytes (bone cells) remain alive in a matrix hardened with calcium phosphate
• Blood

  Extracellular material is the fluid plasma, containing erythrocytes, leukocytes, and thrombocytes
• Three kinds of muscle tissue

  • Smooth
  • Skeletal
  • Cardiac

  
• Smooth muscle

  Found in walls of blood vessels and visceral organs, with a single nucleus

  
• Skeletal muscle


  Usually attached to bone by tendons, with multinucleated fibers (cells)

  
• Cardiac muscle


  Composed of smaller, interconnected cells with a single nucleus, forming a single functioning unit
• Three types of skeletal systems

  • Hydrostatic skeletons
  • Exoskeletons
  • Endoskeletons
• Hydrostatic skeletons


  Fluid-filled central cavities and surrounding muscles, found in soft-bodied invertebrates
• Exoskeletons


  Rigid hard cases surrounding the body, composed of chitin in arthropods

  
• Endoskeletons


  Rigid internal skeletons that form the body's framework and offer surfaces for muscle attachment

  
• Vertebrate endoskeletons have bone and/or cartilage.
• Vertebrate bone


  Made of calcium phosphate
• Vertebrate endoskeletons


  • Have bone and/or cartilage
  • Bone is much stronger than cartilage, and much less flexible
  • Unlike chitin, bone and cartilage are living tissues
  • Can change and remodel in response to injury or physical stress