Tissues Biological tissue is a collection of interconnected cells that perform a similar function within an organism.cells The study of tissue is known as histology, or, in connection with disease, histopathology.histologyhistopathology The classical tools for studying the tissues are the, the, and the optical microscope, though developments in electron microscopy, immunofluorescence, and frozen sections have all added to the sum of knowledge in the last couple of decades.With these tools, the classical appearances of the tissues can be examined in health and disease, enabling considerable refinement of clinical diagnosis and prognosis. There are four basic types of tissue in the body of all animals, including the human body and lower multicellular organisms such as insects. These compose all the organs, structures and other contents. optical microscopeelectron microscopy immunofluorescence animalsmulticellularinsects
EpitheliumEpithelium - Tissues composed of layers of cells that cover organ surfaces such as surface of the skin and inner lining of digestive tract: the tissues that serve for protection, secretion, and absorption. Connective tissueConnective tissue - As the name suggests, connective tissue holds everything together. Connective tissue is characterized by the separation of the cells by an inorganic material, which is called extracellular matrix. Bone and blood are connective tissues.extracellular matrixBoneblood Muscle tissueMuscle tissue - Muscle cells contain contractile filaments that move past each other and change the size of the cell. Muscle tissue also is separated into three distinct categories: visceral or smooth muscle, which is found in the inner linings of organs; skeletal muscle, which is found attached to bone in order for mobility to take place; and cardiac muscle which is found in the heart.smooth muscle skeletal muscle cardiac muscle Nervous tissueNervous tissue - Cells forming the brain, spinal cord and peripheral nervous system.brainspinal cordperipheral nervous system Animal Tissues are groups of similar cells which work together.
Cells – the simplest structure Tissues – epithelial, connective, muscle, nervous Organs – stomach, heart, lungs, brain, intestines, etc. Organ Systems – digestive, respiratory, nervous, skeletal- muscular, etc. Organism – contains all of the above