TISSUES

The Cell Theory

1. all organisms are composed of cells
2. every cell comes from preexisting cell
3. all vital functions occur within cells
4. cells carry hereditary information for metabolism and reproduction.

Animals have a level of organization

1. Cells form tissue
2. Different tissues make up organs
3. Several organs are found within an organ system
4. Organ systems make up the organism

Histology: the study of tissues

See the University of Wisconsin Medical School Histology Atlas for some excellent  slides

Tissue: group of closely related cells, adapted to carry out specific functions.

There are 4 major types of tissue in complex animals:

1. Epithelial tissue: covers body surface, lines body cavities
2. Connective tissue: binds and supports body parts
3. Muscular tissue: Causes body parts to move
4. Nervous tissue: responds to stimuli and transmits impulses from one body part to another

Epithelial Tissue (epithelium)

• cells tightly fitted together, forms continuous sheet, covers body surface, lines cavities
  • more information from
    1. Charles J. Currey, MHA, PA-C; University of Florida PA
    2. ALTRUIS biomedical network
• Epithelium may be simple or stratified
  1. Simple" means the tissue has single layer of cells
  2. "Stratified" means layers piled on top of each other

Five basic types of epithelium [fig. 3.24]:  web links from the University of Wisconsin La Crosse

1. simple squamous (fig. 3.24a)
2. simple cuboidal (fig. 3.24b)
3. simple columnar (fig. 3.24c, d)
4. stratified squamous (fig. 3.24e)
5. transitional

gland: one or more epithelial cells that secretes a special product

CONNECTIVE TISSUE: cells in a matrix

• more information from
  1. characteristics from Charles J. Currey, MHA, PA-C; University of Florida PA Program 
  2. ALTRUIS biomedical network
  3. About.com

Types (8) of Connective Tissue:  web links from the University of Wisconsin La Crosse

1. loose ordinary (figure 3.24g)
2. fibrous-dense ordinary (figure 3.24h)
3. fibrous-elastic
4. reticular
5. adipose tissue (figure 3.24f)
6. cartilage (figure 3.24i, j, k)
7. bone (figure 3.24l)
8. blood (figure 3.24m) and lymph: