Anaphy (lec)

• Cells


  Specialized for particular functions
• Tissues


  Groups of cells with similar structure and function
• Four primary types of tissues

  • Epithelial tissue
  • Connective tissue
  • Muscle tissue
  • Nervous tissue
• Epithelial tissues


  • Found in different areas of the body
  • Body coverings
  • Body linings
  • Glandular tissue
• Functions of epithelial tissues

  • Protection
  • Absorption
  • Filtration
  • Secretion
• Epithelium characteristics


  • Cells fit closely together
  • Tissue layer always has one free surface (apical surface)
  • The lower surface is bound by a basement membrane
  • Avascular (have no blood supply)
  • Regenerate easily if well nourished

  
• Classification of epithelium by number of cell layers

  • Simple – one layer
  • Stratified – more than one layer
• Classification of epithelium by shape of cells

  • Squamous – flattened
  • Cuboidal – cube-shaped
  • Columnar – column-like

  
• Simple epithelium


  • Single layer of cells
• Gland


  One or more cells that secretes a particular product
• Two major gland types

  • Endocrine gland
  • Exocrine gland
• Endocrine glands


  Ductless, secrete hormones
• Exocrine glands


  Empty through ducts to the epithelial surface, secrete enzymes
• Connective tissue


  • Found everywhere in the body
  • Includes the most abundant and widely distributed tissues
• Functions of connective tissue

  • Binds body tissues together
  • Supports the body
  • Provides protection
• Connective tissue characteristics


  • Variations in blood supply
  • Extracellular matrix
• Extracellular matrix


  Non-living material that surrounds living cells
• Elements of extracellular matrix

  • Ground substance
  • Fibers
• Ground substance


  Mostly water along with adhesion proteins and polysaccharide molecules
• Types of fibers


  • Collagen fibers
  • Elastic fibers
  • Reticular fibers
• Bone (osseous tissue)


  • Composed of bone cells in lacunae (cavities) and hard matrix of calcium salts with large numbers of collagen fibers
• Cellular components of bone

  • Osteoblasts- active bone cells
  • Osteocytes- inactive osteoblasts
  • Osteoclasts- bone-destroying cells
• Hyaline cartilage


  • Most common cartilage, composed of abundant collagen fibers and rubbery matrix
• Elastic cartilage


  • Provides elasticity, supports the external ear, Eustachian or auditory tube, larynx, epiglottis
• Fibrocartilage


  • Highly compressible, forms cushion-like discs between vertebrae, pubic symphysis, joints subject to severe strain
• Dense connective tissue


  • Main matrix element is collagen fibers, cells are fibroblasts, examples are tendons and ligaments
• Areolar connective tissue


  • Most widely distributed connective tissue, soft, pliable, contains all fiber types, found in dermis, superficial fascia, subcutaneous layer, mucous membranes, around blood vessels & nerves
• Adipose tissue


  • Matrix is an areolar tissue in which fat globules predominate, functions to insulate the body, protect some organs, and serve as a site of fuel storage
• Reticular connective tissue


  • Delicate network of interwoven fibers, forms stroma (internal supporting network) of lymphoid organs like lymph nodes, spleen, and bone marrow
• Blood


  • Blood cells surrounded by fluid matrix, fibers are visible during clotting, functions as the transport vehicle for materials
• Types of blood cells

  • Red blood cells/Erythrocytes
  • Platelets/Thrombocytes
  • White Blood Cells (leukocytes)
• Classification of white blood cells

  • Granulocytes (contains granules in cytoplasm)
  • Agranulocytes (no granules in cytoplasm)
• Functions of blood


  • Circulates materials around the body (gases, nutrients, & hormones)
  • Maintains homeostasis by controlling body temperature and pH of body fluids
  • Protection through phagocytosis & antibody production
• Muscle tissue


  Function is to produce movement
• Types of muscle tissue

  • Skeletal muscle
  • Cardiac muscle
  • Smooth muscle
• Skeletal muscle


  • Can be controlled voluntarily, cells are long and cylindrical, cells are striated, cells have more than one peripherally-located nucleus (multinucleated)
• Cardiac muscle


  • Found only in the heart, function is to pump blood (involuntary), cells attached to other cardiac muscle cells at intercalated disks, cells are striated, one nucleus per cell
• Smooth muscle


  • Involuntary muscle, surrounds hollow organs, spindle-shaped cells, no visible striations, one nucleus per cell
• Nervous tissue


  Composed of neurons, neuroglia, & peripheral glia cells, function is to send impulses to other areas of the body (neurons), support & nourishes neurons (neuroglia)
• Functions of nervous tissue

  • Irritability
  • Conductivity