It, essentially, floats off of the back of the chest, as it is connected to the body primarily by muscle. In fact, there are 17 muscles that attach to the scapula. The scapula has a joint that wraps around from the back to the front of the shoulder called the acromion.
Their unique composition and design allows bones to be relatively Anatomy of bones and strong, while remaining lightweight. It is the bone mineralization that give bones rigidity.
Bone is actively constructed and remodeled throughout life by special bone cells known as osteoblasts and osteoclasts. Within any single bone, the tissue is woven into two main patterns, known cortical and cancellous bone, and each with different appearance and characteristics.
Cortical bone[ edit ] Cross-section details of a long bone The hard outer layer of bones is composed of cortical bone also called compact bone being much denser than cancellous bone.
It forms the hard exterior cortex of bones. It consists of multiple microscopic columns, each called an osteon. Each column is multiple layers of osteoblasts and osteocytes around a central canal called the haversian canal.
Volkmann's canals at right angles connect the osteons together. The columns are metabolically active, and as bone is reabsorbed and created the nature and location of the cells within the osteon will change. Cortical bone is covered by a periosteum on its outer surface, and an endosteum on its inner surface.
The endosteum is the boundary between the cortical bone and the cancellous bone. Cancellous bone[ edit ] Micrograph of cancellous bone Cancellous bone, also called trabecular or spongy bone,  is the internal tissue of the skeletal bone and is an open cell porous network.
Cancellous bone has a higher surface-area-to-volume ratio than cortical bone because it is less dense. This makes it weaker and more flexible. The greater surface area also makes it suitable for metabolic activities such as the exchange of calcium ions.
Cancellous bone is typically found at the ends of long bones, near joints and in the interior of vertebrae. Cancellous bone is highly vascular and often contains red bone marrow where hematopoiesisthe production of blood cells, occurs. The primary anatomical and functional unit of cancellous bone is the trabecula.
The trabeculae are aligned towards the mechanical load distribution that a bone experiences within long bones such as the femur. As far as short bones are concerned, trabecular alignment has been studied in the vertebral pedicle.
Within these spaces are bone marrow and hematopoietic stem cells that give rise to plateletsred blood cells and white blood cells. In adults, red marrow is mostly found in the bone marrow of the femur, the ribs, the vertebrae and pelvic bones.
These cells include osteoblastswhich are involved in the creation and mineralization of bone tissue, osteocytesand osteoclastswhich are involved in the reabsorption of bone tissue. Osteoblasts and osteocytes are derived from osteoprogenitor cells, but osteoclasts are derived from the same cells that differentiate to form macrophages and monocytes.
These cells give rise to other cells, including white blood cellsred blood cellsand platelets. Osteoblasts are mononucleate bone-forming cells. They are located on the surface of osteon seams and make a protein mixture known as osteoidwhich mineralizes to become bone.
Osteoid is primarily composed of Type I collagen. Osteoblasts also manufacture hormonessuch as prostaglandinsto act on the bone itself.Apr 09, · Anatomy of the typical long bone, as well as microscopic anatomy of bone tissue. Bone Basics and Bone Anatomy Have you ever seen fossil remains of dinosaur and ancient human bones in textbooks, television, or in person at a museum?
It's easy to look at these and think of bones as dry, dead sticks in your body, but this couldn't be further from the truth. The human skeleton of an adult consists of bones.
It is composed of bones at birth, but later decreases to 80 bones in the axial skeleton and bones in the appendicular grupobittia.com small supernumerary bones, such as some sesamoid bones, are not included in this count.
Apr 09, · Anatomy of the typical long bone, as well as microscopic anatomy of bone grupobittia.com: Jon Lund. A long bone has two parts: the diaphysis and the epiphysis. The diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone. The hollow region in the diaphysis is called the medullary cavity, which is filled with yellow marrow.
The walls of the diaphysis are composed of dense and hard compact bone. Learn anatomy bones with free interactive flashcards. Choose from different sets of anatomy bones flashcards on Quizlet.