Tissue

Tissue

1. Epithelial

   • Functions
     • 1) Provide physical protection
     • 2) Control permeability
     • 3) Provide sensations
     • 4) Provided specialized secretions
   • Specializations
     • Move fluids over/through epithelium
     • Produce secretions
     • Polarity
       • Apical surface
       • basolateral surface
     • Cell Junctions
       • Gap Junctions
         • From intracellular passageway between membranes of adjacent cells
         • Allows rapid communication
         • Allows ions and molecules to pass through
         • Coordinate contractions in heart muscles
       • Tight Junctions
         • Between two plasma membranes
         • prevent passage of water and solutes
       • Desmosomes
         • CAMs and proteoglycans link opposing plasma membrane
         • Spot desmosomes
           • Ties cell together
           • Occurs in patches on cell membranes
   • Classifications
     • Based on shape
       • Squamous
       • Cubodial
       • columnar
     • Based on layers
       • Simple epithelium
       • Stratified epithelium
   • Glands
     • Endocrine
       • Release hormones entering bloodstream
     • Exocrine
       • Discharge excretions through ducts onto epithelial surface

2. Connective tissue

   • Connective tissue proper
     • Loose connective tissue
       • Areolar tissue
         • Least specialized
         • Open framework
         • Viscous ground substance (Subcutaneous layer)
       • Adipose tissue
         • Least specialized
           • Contains many fat cells that do not divide
         • Expands to store fats
       • Reticular tissue
         • Provides support
         • Fibres form a complex 3-D stroma
         • Support functional cells of organs
     • Dense connective tissue
       • Dense regular connective tissue
         • Tendons
           • Attach muscles to bones
         • Ligaments
           • Connect one bone to another and stabilize organs
         • Aponeuroses
           • Tendinous sheets attached to a broad, flat muscle to another structure
       • Dense irregular connective tissue
         • - Interwoven network of collagen fibers . provides strength to dermis -
   • Fluid connective tissue
     • Blood
       • Contains plasma
       • Contains cells and fragments
         • RBC
         • WBC
         • Platelets
   • Supporting connective tissue
     • Cartilage
       • Hyaline
         • Most common type that is tough and flexible
         • Reduces friction between bones
       • Elastic
         • Supportive but bends easily
         • found in external ear
       • Fibrocartilage
         • Durable and tough
         • limits movement and bone to bone contact
     • Bones
       • Osseous tissue
       • Periosteum covers bone
       • fibrous (outer) layer and cellular (inner) layer