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Each osteon consists of concentric layers, or lamellae, of compact bone tissue that surround a central canal, the Haversian canal. The Haversian canal contains the bone's blood supplies. The boundary of an osteon is the cement line. Each Haversian canal is surrounded by varying number (5-20) of concentrically arranged lamellae of bone matrix.
The human skeleton of an adult usually consists of around 206 bones, depending on the counting of Sternum (which may alternatively be included as the manubrium, body of sternum, and the xiphoid process). [1] It is composed of 270 bones at the time of birth, [2] but later decreases to 206: 80 bones in the axial skeleton and 126 bones in the ...
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.
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.
The long bone category includes the femora, tibiae, and fibulae of the legs; the humeri, radii, and ulnae of the arms; metacarpals and metatarsals of the hands and feet, the phalanges of the fingers and toes, and the clavicles or collar bones. The long bones of the human leg comprise nearly half of adult height.
This tissue provides support to plants and also stores food. Chlorenchyma is a special type of parenchyma that contains chlorophyll and performs photosynthesis. In aquatic plants, aerenchyma tissues, or large air cavities, give support to float on water by making them buoyant. Parenchyma cells called idioblasts have metabolic waste.
The formation of woody tissue is an example of secondary growth, a change in existing tissues, in contrast to primary growth that creates new tissues, such as the elongating tip of a plant shoot. The process of wood formation ( lignification ) is commonest in the spermatophytes (seed bearing plants) and has evolved independently a number of times.
A sesamoid bone is a small, round bone that, as the name suggests, is shaped like a sesame seed. These bones form in tendons (the sheaths of tissue that connect bones to muscles) where a great deal of pressure is generated in a joint. The sesamoid bones protect tendons by helping them overcome compressive forces.