Epithelial tissue is a layer of cells lining the surface of the body, the body cavity, the mucous membranes of the internal organs, the digestive tract, the respiratory system, the genitourinary tract. The tissue is composed of epithelial cells located on a thin basement membrane.
Muscular tissues are tissues that consist of elongated cells and muscle fibers that respond to various stimuli and provide the contraction. These tissues mediate the movement of the whole body and organs within the body.
Nerve tissues represent a system of specialized structures that perceive stimuli by generating nerve impulses and transmit these impulses to the effectors, connecting the body with the environment. Nerve tissue provides the interaction of tissues, organs, and systems of the body and their regulation.
Connective tissue is the tissue that is not directly responsible for the work of any organ or system of organs but plays an auxiliary role in all organs, accounting for 60–90% of their mass. The tissue performs supporting, structural, protective, and trophic functions.