Tissue: A group or layer of cells that perform specific functions. For example, muscle tissue is a group of muscle cells.issue: A group or layer of cells that perform specific functions. For example, muscle tissue is a group of muscle cells.
1 The skin is a barrier to the outside world protecting the body from infection, radiation, and extremes of temperature.  There are many types of wounds that can damage the skin including abrasions, lacerations, rupture injuries, punctures, and penetrating wounds.
Contusions are common types of bruises that are caused by trauma, often blunt-force injury, that damages and breaks open the tiny blood vessels in the tissues of the skin, mucus membranes or other organs. Contusions are often accompanied by pain and swelling due to the bodyâs inflammatory response to injury.urpura. Purpura is caused by spontaneous leaking of blood from tiny blood vessels (capillaries). It is a type of bruising that causes purple or red flat spots or patches on the skin and mucus membranes. Purpura that results in tiny spots on the skin is called petechiae.