By: Jessica Leigh Bosley
A tissue is
Tissue is a cellular organizational level intermediate between cells and a complete organism. Hence, a tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function
The Four Types of tissue.
-Epithelial. Functions include protection, absorption, filtration, and secretion.
- Connective. Function include protection, supporting, and binding together other body tissues.
- Nervous. Functions include irritability and conductivity.
-Muscle. Functions include contracting or shortening to produce movement.
Epithelial tissues are classified into two groups. Simple Epithelial and Stratified Epithelial. There are three different shapes; Squamous, Cuboidal, and Columnar.
Connective tissues are classified into eight groups. Bone, Cartilage, Dense Connective Tissue, Loose Connective Tissue, Areolar Tissue, Adipose Tissue, Reticular Connective Tissue, and Vascular Tissue.
Nervous tissues are classified into three groups. Spinal Chord, Nerves, and Brain
Muscle tissues are classified into three groups. Skeletal, Cardiac, and Smooth.
Specialization of Epithelia
The membranes always have one free (unattached) surface or edge. This so-called Apical Surface is exposed to the body's exterior or to the cavity of an internal organ. The exposed surfaces of some epithelial are slick and smooth, but others exhibit cell surface modifications, such as microvilli or cilia.
The lower surface of an epithelium rests on a basement membrane, a structureless material secreted by the cells.
Epithelial tissues have no blood supply of their own (that is, they are avascular) and depend on diffusion from the capillaries in the underlying connective tissue for food and oxygen.
If well nourished, epithelial cells regenerate themselves easily.
Where all of these tissues can be found
Epithelial-The outer layer of skin. Lining the body cavities.
Connective-Found everywhere in the body.
Nervous-Found everywhere in your body.
Muscle-Found everywhere in the body.