Anatomy final

• Chapter 4 Outline


  • Epithelial Tissue
  • Connective Tissue
  • Body Membranes
  • Muscle Tissue
  • Nervous Tissue
• Extracellular matrix


  Generally composed of water, protein fibers, dissolved molecules. Composition, volume and consistency is different across tissues.
• Types of Tissue


  • Epithelial
  • Connective
  • Muscular
  • Nervous
• Epithelial Tissue


  • Covers body surface and all body cavities
  • Organs are lined on the outside and inside by epithelial tissue
  • Majority of glands are derived from epithelial tissue
  • Possesses little to no extracellular matrix
• Desosomes


  Created by protein plaques
• Gap junctions


  Have openings that allow for communication between cells
• Characteristics of Epithelial Tissue

  • Cellularity: Composed almost entirely of cells - little extracellular matrix
  • Cells are bound together by several types of intercellular junctions
  • Polarity: Epithelial cells have an apical surface and a basal surface
  • Attachment: Basal surface attaches to basement membrane
  • Avascularity: Epithelial tissues lack blood vessels
  • Innervation: Epithelia are richly innervated to detect changes in environment
  • High regeneration capacity: Epithelial cells are quickly replaced
• Epithelial tissue is the cheapest kind of cells
• Functions of Epithelial Tissue

  • Physical protection
  • Selective permeability
  • Secretion
  • Sensation
• Basement Membrane


  • Between epithelium and underlying connective tissue
  • Provides physical support and anchoring of epithelial tissue
  • Acts as a defense regulating passage of large molecules between epithelium and connective tissue
• Specialized Structures of Epithelial Tissue: Intercellular Junctions

  • Tight Junctions
  • Adhering Junctions
  • Desmosomes
  • Gap Junctions
• Tight Junctions


  Encircle cells near their apical surface, act as "gatekeepers" between an external and internal environment
• Adhering Junctions


  Formed completely around the cell deep to the tight junction, microfilaments act like a purse string to stabilize the apical surface of the epithelial cell
• Desmosomes


  Like a button or snap between adjacent cells, appear at locations of mechanical stress between cells sharing this type of junction
• Gap Junctions


  span the intercellular space between neighboring cells, allow adjacent cells to communicate with each other by the flow of ions and small molecules
• Classification of Epithelial Tissue by Number of Cell Layers

  • Simple epithelium
  • Stratified epithelium
  • Pseudostratified epithelium
• Classification of Epithelial Tissue by Cell Shape

  • Squamous
  • Cuboidal
  • Columnar
• Glands


  Individual cells or multicellular organs that perform a secretory function, produce mucin, hormones, enzymes, waste products
• Types of Glands


  • Endocrine glands
  • Exocrine glands
• Exocrine Glands


  Possess ducts and their cells secrete products into their ducts
• Structure of Exocrine Glands

  • Ducts carry products to superficial surface
  • Secrete products through a duct onto body surfaces or into body cavities
  • Goblet cells are unicellular exocrine glands
  • Multicellular exocrine glands are often enclosed in a fibrous capsule, divided into lobes, with a connective tissue stroma supporting and organizing the gland
  • Microscopic lobules contain secretory acini and ducts
• Classification of Exocrine Glands by Duct Type

  • Simple
  • Compound
• Classification of Exocrine Glands by Secretory Portion Shape

  • Tubular
  • Acinar
  • Tubuloacinar
• Classification of Exocrine Glands by Secretion Type

  • Serous
  • Mucous
  • Mixed
• Classification of Exocrine Glands by Secretion Method

  • Merocrine
  • Holocrine
  • Apocrine
• Connective tissue is the most diverse, abundant, widely distributed, and structurally varied of the four main tissue types
• Stroma


  Cells and tissues that provide structure
• Components of Connective Tissue

  • Blood
  • Tendons
  • Ligaments
  • Fat
  • Bones
  • Cartilage
• Functions of Connective Tissue

  • Physical protection
  • Support and structural framework
  • Binding of structures
  • Storage
  • Transport
  • Immune protection
• Types of Connective Tissue Proper

  • Loose connective tissue
  • Dense connective tissue
• Areolar Connective Tissue


  • Scattered fibroblasts, abundant ground substance, web of fibers
  • Surrounds and protects, connects epithelia to deeper tissues
• Adipose Connective Tissue


  • Tightly packed adipocytes
  • Stores energy, cushions organs, insulates
• Reticular Connective Tissue


  • Scattered fibroblasts, white blood cells, reticular fibers, gel-like ground substance
  • Provides supportive framework
• Dense Regular Connective Tissue


  • Densely packed parallel collagen fibers, fibroblasts, scarce ground substance
  • Resists stress in one direction
• Dense Irregular Connective Tissue

  • Randomly arranged collagen fibers, fibroblasts, ground substance
  • Resists stress in all directions
• Elastic Connective Tissue


  • Many branching elastic fibers, fibroblasts, ground substance
  • Allows stretching and recoil
• Cartilage


  • Firm, gel-like extracellular matrix composed of protein and ground substance
  • Cells are called chondrocytes, occupy small spaces enclosed by their ECM called lacunae
  • Strong and resilient to provide support and withstand deformation
  • Usually covered by perichondrium
• Types of Cartilage


  • Hyaline Cartilage
  • Fibrocartilage
  • Elastic Cartilage
• Bone


  • 2/3 of bone's weight is inorganic, 1/3 is organic
  • Organic parts provide flexibility, inorganic parts provide compressional strength
  • Periosteum is a dense irregular connective tissue covering
  • Mature bone cells are called osteocytes
  • Two forms: compact bone and spongy bone
• Compact Bone


  Calcified matrix organized in osteons, protects organs, provides levers for movement, stores calcium