Search results
Results From The WOW.Com Content Network
Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. [2] In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). [3] It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells.
Located in the main shaft of a long bone (consisting mostly of compact bone), the medullary cavity has walls composed of spongy bone (cancellous bone) and is lined with a thin, vascular membrane . [1] [2] This area is involved in the formation of red blood cells and white blood cells, and the calcium supply for bird eggshells. The area has been ...
Flat bones are thin and generally curved, with two parallel layers of compact bone sandwiching a layer of spongy bone. Most of the bones of the skull are flat bones, as is the sternum. [39] Sesamoid bones are bones embedded in tendons. Since they act to hold the tendon further away from the joint, the angle of the tendon is increased and thus ...
Diagram of a typical long bone showing both cortical (compact) and cancellous (spongy) bone. Haversian canals [i] (sometimes canals of Havers, osteonic canals or central canals) are a series of microscopic tubes in the outermost region of bone called cortical bone. They allow blood vessels and nerves to travel through them to supply the osteocytes.
It is a subclass of trabecular bone. [2] In the cranial bones, the layers of compact cortical tissue are familiarly known as the tables of the skull; the outer one is thick and tough; the inner is thin, dense, and brittle, and hence is termed the vitreous table. The intervening cancellous tissue is called the diploë.
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.
Diagram of a typical long bone showing both compact (cortical) and cancellous (spongy) bone. Osteons on cross-section of a bone. 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.
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 appendicular skeleton. 172 of 206 bones are part of a pair and the remaining 34 are unpaired. [3] Many small accessory bones, such as sesamoid bones, are not included in this.