What is Tissue?
{{otheruses}} [[Image:Stem-histology-cross-section-tag.svg|thumb|right|250px|Cross-section of a [[flax]] plant stem with several layers of different tissue types:<br> 1. [[pith]]<br> 2. [[protoxylem]]<br> 3. [[xylem]] <br> 4. [[phloem]] <br> 5. [[sclerenchyma]] ([[:en:bast fibre|bast fibre]])<br> 6. [[cortex (botany)|cortex]]<br> 7. [[epidermis (botany)|epidermis]]]] A '''Tissue''' forms part of an [[Organ (anatomy)|organ]] in plants or animals. Tissues are groups of [[cells]] that work together to do a job in the body. They are a group of cells having the same origin, structure and [[Function (biology)|function]]. The cells look the same or almost the same. The work the cells in a tissue do is the same or almost the same. The four main kinds of tissue in animals are: # [[connective tissue]] # [[muscle]]s # [[nerve]]s # [[epithelial tissue]] [[Organ (anatomy)|Organs]] are made up of more than one kind of tissue. The [[heart]] is an organ. It is made up of different tissues. It has [[muscle]] tissue called myocardium. It has [[connective tissue]] on the inside (endocardium), and on the outside (pericardium). The heart has [[valve]]s that make sure the blood goes the right way through the heart. So the heart is an organ made from several tissues. The study of the structure of tissues under a [[microscope]] is called [[histology]]. {{Biology-stub}} [[Category:Tissues]]