brasheranatomytissues

Tissues are groups of cells that have similar shapes and functions. There are four basic types of tissues:
 * //Epithelial tissues// lie on the surfaces of the body. They form your skin and line all of your body spaces. They have no blood supply (//avascular)// and obtain food and oxygen from underlying tissues by diffusion. Because they are exposed to much abrasion, they are easily damaged and are quickly replaced.
 * //Connective tissues// fill many spaces in the body. There are very few cells in this tissue, but lots of a nonliving substance called the //extracellular matrix.// Bone is the hardest form of connective tissue, followed by cartilage. Loose connective tissue is found cushioning the body organs, while adipose (fat) tissue helps provide warmth to the body. Blood is the only connective tissue that has a matrix that consists of a liquid.
 * //Muscle tissue// has the very special ability to contract, or shorten, to allow your body to move.
 * //Nervous tissue// is able to receive information, process it, and send messages out to various parts of the body.