Body Tissues

Tissue is a group of cells that have similar structure and that function together as a unit. A nonliving material, called the intercellular matrix, fills the spaces between the cells. This may be abundant in some tissues and minimal in others. The intercellular matrix may contain special substances such as salts and fibers that are unique to a specific tissue and gives that tissue distinctive characteristics. There are four main tissue types in the body: epithelial, connective, muscle, and nervous. Each is designed for specific functions.

Epithelial Tissue
Connective Tissue
Muscle Tissue
Nervous Tissue

Referrence:Tissue(Chinese Version)

Biological tissue, From Wikipedia, the free encyclopedia

Biological tissue is a collection of interconnected cells that perform a similar function within an organism.
The study of tissues is known as histology, or, in connection with disease, histopathology.
The classical tools for studying the tissues are the wax block, the tissue stain, and the optical microscope, though developments in electron microscopy, immunofluorescence, and frozen sections have all added to the sum of knowledge in the last couple of decades.
With these tools, the classical appearances of the tissues can be examined in health and disease, enabling considerable refinement of clinical diagnosis and prognosis.

Animal tissues
There are four basic types of tissue in the body of all animals, including the human body and lower multicellular organisms such as insects. These compose all the organs, structures and other contents.

• Epithelium - Tissues composed of layers of cells that cover organ surfaces such as surface of the skin and inner lining of digestive tract. The tissues serve for protection, secretion, and absorption.
• Connective tissue - As the name suggests, connective tissue holds everything together. Blood is considered a connective tissue. These tissues contain extensive extracellular matrix.
• Muscle tissue - Muscle cells contain contractile filaments that move past each other and change the size of the cell. Muscle tissue also is separated into three distinct categories: visceral or smooth muscle, which is found in the inner linings of organs; skeletal muscle, which is found attached to bone in order for mobility to take place; and cardiac muscle which is found in the heart.
• Nervous tissue - Cells forming the brain, spinal cord and peripheral nervous system.
• Areolar connective tissue - A pliable, mesh-like tissue with a fluid matrix that funtions to cushion and protect body organs.