Chapter 4- Tissues & Living Fabric
Chapter 4
Tissue: The Living Fabric
4.1 What are tissues? * Groups of cells that are similar in structure and perform a common or related function * There are four basic types of tissues: 1) Epithelial (covering) 2) Connective (support) 3) Muscle (movement) 4) Nervous (communication and control) * The study of tissues is known as histology
4.2 Preparing Human Tissue for Microscopy
Requirements
* Specimen must be fixed (preserved) * Specimen must be cut into sections (slices) thin enough to transmit light or electrons * Specimen must be stained to enhance contrast
Light Microscopy * The stains used consist of negatively or positively charged molecules that bind within the tissue to macromolecules of the opposite charge * The stains distinguish different anatomical structures because different parts of cells and tissues take up different dyes
Transmission Electron Microscopy * Tissue sections stained with heavy metal salts * Metal salts deflect electrons in the beam to different extents * Shades of gray, color is a property of light, not electron waves
Scanning Electron Microscopy * Provides three-dimensional pictures of an un-sectioned tissue surface
4.3 Epithelial Tissue * Epithelial tissue or an epithelium, is a sheet of cells that covers a body surface or lines a body cavity * It occurs in the body in two ways 1. Covering and lining epithelium- Forms outer layer of skin and lines organs 2. Glandular epithelium- fashions glands of body (secretion) * Functions 1. Protection 2. Absorption 3. Filtration 4. Excretion 5. Secretion 6. Sensory Reception
-The epithelium of the skin protects underlying tissues from mechanical and chemical injury and bacterial invasion and contains nerve endings that respond to various stimuli acting at the skin surface.
Special Characteristics- * Polarity: the cell regions near the surface differ from those
Tissue: The Living Fabric
4.1 What are tissues? * Groups of cells that are similar in structure and perform a common or related function * There are four basic types of tissues: 1) Epithelial (covering) 2) Connective (support) 3) Muscle (movement) 4) Nervous (communication and control) * The study of tissues is known as histology
4.2 Preparing Human Tissue for Microscopy
Requirements
* Specimen must be fixed (preserved) * Specimen must be cut into sections (slices) thin enough to transmit light or electrons * Specimen must be stained to enhance contrast
Light Microscopy * The stains used consist of negatively or positively charged molecules that bind within the tissue to macromolecules of the opposite charge * The stains distinguish different anatomical structures because different parts of cells and tissues take up different dyes
Transmission Electron Microscopy * Tissue sections stained with heavy metal salts * Metal salts deflect electrons in the beam to different extents * Shades of gray, color is a property of light, not electron waves
Scanning Electron Microscopy * Provides three-dimensional pictures of an un-sectioned tissue surface
4.3 Epithelial Tissue * Epithelial tissue or an epithelium, is a sheet of cells that covers a body surface or lines a body cavity * It occurs in the body in two ways 1. Covering and lining epithelium- Forms outer layer of skin and lines organs 2. Glandular epithelium- fashions glands of body (secretion) * Functions 1. Protection 2. Absorption 3. Filtration 4. Excretion 5. Secretion 6. Sensory Reception
-The epithelium of the skin protects underlying tissues from mechanical and chemical injury and bacterial invasion and contains nerve endings that respond to various stimuli acting at the skin surface.
Special Characteristics- * Polarity: the cell regions near the surface differ from those