CBH 19 Epithelial tissue

• General features

  Closely packed cells with many cell junctions , little extracellular material , Cells sit on basement membrane generally avascular , good nerve supply

  
• Functions

  Protections filtration , secretion , digestion , absorption , sensory reception
• epithelia according to layer number

  Simple stratified pseudostratified

  
• Epithelia according to shape

  Squamous , cuboidal, columnar
• Specializations


  Keratinized or non-keratinized with connective papillae , microvilli , cilia , goblet cells
• Covering epithelia

  Unicellular gland , intraepithelial , pluricellular gland , glandular epithelium
• Types of glands

  ExocrineEndocrine
• Exocrine gland


  Secrete to the exterior or to a cavity that leads to the exterior, have ducts
• Endocrine Glands


  Secrete hormones to the blood, lack ducts
• Shape of secretory portion

  Tubular , acinar , tubuloacinar

  
• Branching of ducts

  simple , compound
• Types of secretions

  Serous, mucous, seromucous, others: sweat, milk and sebum