There are four main types of tissue in the body:
Epithelial Tissue: cover the various internal and external surfaces of the body. These form an effective barrier between the body and its surroundings, some also respond to stimuli from the environment. The are responsible for absorption, secretion and excretion and found in tear, sweat and saliva glands.
Connective Tissue: binds tissues together and holds organs in place. They are widely separated by a matrix with spaces filled by fluid, fibers and solid materials. They can also stores fat and performs other functions.
Muscle Tissue: muscle movements are the result of the contraction of elongated or cylindrical muscle cells, fibers. They are composed of proteins actin and myosin. Skeletal and cardiac muscles are composed of this.
Nervous Tissue: This is found within the central nervous system and in the peripheral nervous system that consists of nerves. This is also found in every organ of the body. This is consisted of neurons and glial cells. Neurons are capable of responding to physical and chemical stimuli by creating an impulse. The Glial cells support and protect the neurons. Together these controls spontaneous activity, physiological functions, learned information and initiates motor activities.