Membranous Epithelia

• Simple Squamous Epithelia

  • single layer of flat cells
• Simple squamous epithelia

  Specimen: Frog liver x.s.

  • arteriole/venule
• Simple cuboidal epithelia

  • single layer of cube-shaped cells
  • line small ducts and tubules
• Simple cuboidal epithelia

  Specimen: Frog kidney x.s

  • tubules comprising main mass of organ
• Simple Columnar epithelia

  • Single layer of elongated cells
• Simple columnar epithelia

  Specimen: Frog small intestine x.s

  • Innermost layer
  • Lining villi of small intestine
• Stratified epithelia (on skin)

  • consist of squamous (flat) epithelial cells on surface; transparent
  • Layers of cuboidal or columnar epithelial cells beneath; highly stained
• Stratified squamous epithelia (internal cavities)

  • Stained with IKI
  • Non-keratinized
  • lines most internal cavities such as entire surface of oral mucosa and esophagus
• Stratified epithelia

  Specimen: Frog skin x.s.
• Stratified squamous epithelia (internal cavities)

  Specimen: Human cheek cells
• Functional unit of grandular epithelia

  • unicellular
  • multicellular
• Cells of grandular epithelium tissues secrete cehmical substances for use within the body or for discharge into the surroundings
• Multicellular glands may be classified as

  • exocrine
  • endocrine
• Goblet cells

  • unicellular gland
  • Interspersed among columnar epithelia
• Goblet Cells

  • Specimen: Frog small intestine x.s.
• Cutaneous glands

  • Body is round and hollow
  • Beneath epithelial layers
  • Body connects to the surface through narrow opening: neck
• Extracellular matrix

  • abundant in connective tissues where specific cell types are dispersed or distributed
• Fibrous connective tissue

  • join and support various body structures
• Fibrocytes

  • cells that secrete extracellular matrix
• Specialized connective tissues:

  • cartilage
  • bone
  • blood
• Loose connective tissue:

  • "packing material" of the body
  • anchors the various blood vessels, nerves, muscles, and body organs
• Dense connective tissue

  • found in skin, tendons, ligaments
  • primarily consists of densely packed fibers (regular or irregular in arrangement)
• Cartilage

  • flexible supportive tissue
• Chondrocytes

  • cells of cartilage that secrete ECM
• Chondroitin sulfate

  • amorphous ground substance taht make up the matrix of cartilage
• Chondroitin sulfate

  • gives cartilage resilience, network of collagen fibers and elastic fibers
• Types of cartilage

  • hyaline
  • fibrocartilage
  • elastic
• Hyaline Cartilage

  • most abundant type of cartilage
• Hyaline Cartilage

  • type of cartilage characterized by very fine collagen fibers that are widely dispersed in gelatinous ground substance
• Lacunae

  • egg-shaped compartments of chondrocytes in hyaline cartilage
• Bone

  • provides internal support and protection to internal organs
  • anchors muscles and give them leverage to move
• Osteocytes

  • cells that make up bone
  • embedded in mineralized ground substance: hydroxyapatite
• 2 Types of bone tissue:

  • spongy or cancellous
  • compact
• Compact bone tissue

  • forms external hard layer
• Spongy or cancellous bone tissue

  • forms in certain inner parts of all bones
• Osteon

  • basic functional and histological unit of compact bone
• What is the other name for osteon?

  Haversian canal system
• Haversian Canal

  • runs longitudinally, parallel to bone
  • Surrounded by concentric rings of extracellular matrix
• Lamella

  • concentric rings of ECM that surrounds Haversian canal
• Lacunae

  • Interspersed along concentric rings
  • Spaces housing osteocytes