Organ (biology)
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In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tis
The liver and gallbladder of a sheep
1905 diagram of the internal organs of human body
Relationship of major animal lineages with indication of how long ago these animals shared a common ancestor. On the left, important organs are shown, which allows us to determine how long ago these may have evolved.
Strobilus of Equisetum telmateia
Tissue (biology)
Videos
In biology, tissue is an assembly of similar cells and their extracellular matrix from the same embryonic origin that together carry out a specific function. Tissues occupy a biological organizational
Organ (biology)
…In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed…
Microscopic view of a histologic specimen of human lung, consisting of various tissues: blood, connective tissue, vascular endothelium and respiratory epithelium, stained with hematoxylin and eosin.
Cross section of 2-year-old Tilia americana, highlighting xylem ray shape and orientation
Cross section through skeletal muscle and a small nerve at high magnification (H&E stain)
Xavier Bichat (1771–1802)