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In osteology, the osteon or haversian system (/ h ə ˈ v ɜːr. ʒ ən /; named for Clopton Havers) is the fundamental functional unit of much compact bone. Osteons are roughly cylindrical structures that are typically between 0.25 mm and 0.35 mm in diameter . [ 1 ]
Chloroplasts in leaf cells of the moss Mnium stellare. Plant anatomy or phytotomy is the general term for the study of the internal structure of plants.Originally, it included plant morphology, the description of the physical form and external structure of plants, but since the mid-20th century, plant anatomy has been considered a separate field referring only to internal plant structure.
Organography as a scientific study starts with Aristotle, who considered the parts of plants as "organs" and began to consider the relationship between different organs and different functions. In the 17th century Joachim Jung, [ 1 ] clearly articulated that plants are composed of different organ types such as root, stem and leaf, and he went ...
The main tissues that make up an organ tend to have common embryologic origins, such as arising from the same germ layer. Organs exist in most multicellular organisms. In single-celled organisms such as members of the eukaryotes, the functional analogue of an organ is known as an organelle. In plants, there are three main organs. [3]
A bone is a rigid organ [1] that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility.
Plant structures or organs fulfil specific functions, and those functions determine the structures that perform them. Among terrestrial (land) plants, the vascular and non-vascular plants (Bryophytes) evolved independently in terms of their adaptation to terrestrial life and are treated separately here (see Bryophytes ).
The skeleton is a large organ that is formed and degraded throughout life in the air-breathing vertebrates. The skeleton, often referred to as the skeletal system, is important both as a supporting structure and for maintenance of calcium, phosphate, and acid-base status in the whole organism. [ 5 ]
Vascular plants have two distinct organ systems: a shoot system, and a root system. The shoot system consists stems, leaves, and the reproductive parts of the plant (flowers and fruits). The shoot system generally grows above ground, where it absorbs the light needed for photosynthesis. The root system, which supports the plants and absorbs ...