humananatomyfacts:

All of the cells in the human body can be classified into one of these four basic tissue groups.

Epithelial tissues cover body and organ surfaces, as well as line cavities and ducts within the body. They protect the body from invasion and often secrete or absorb substances.

Connective tissues support other body tissues, transmit mechanical and other forces, and in some case even act as filters.

Muscle tissues consist of cells that have the ability to contract. These contractions help move body limbs, pump blood, and produce a squeezing pressure in organs such as the intestine and uterus.

Nervous tissues contain cells called neurons and act as lines of communication and control between body parts. Nervous tissue also contains glial cells which help to support and provide nutrients, provide electrical insulation between them, and scavenge cellular debris from foreign matter.

(via wildlydistorted)