What Do You Know About Bone Physiology , Formation , Remodeling Flashcards

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Haversian Canal System


An easy way to remember the work of osteoblasts, osteoclasts, and osteocytes is

Osteoblasts giveth.
Osteoclasts taketh away.
Osteocytes maintaineth.
Osteoblasts
Osteoblasts are the builders and make collagen and hydroxyapatite. Some of the osteoblasts become buried in their matrix and then they are referred to as osteocytes. The rest of the osteoblasts cover the new bone's surface. Waves of osteoblasts that move into the area form new layers of bone.
Osteoclasts Osteoclasts are larger cells whose function is to dissolve bone by acting on the mineral matrix. They make enzymes such as collagenase, which breaks down collagen. Osteoclasts also secrete various acids that can dissolve the hydroxyapatite structure.
Osteocyte After the osteoblasts are buried in bone, they're referred to as osteocytes. Osteocytes account for 90 percent of all cells in the skeleton
Calaliculi Osteoblasts change their shape and become buried in their matrix, connected to each other only by thin processes called canaliculi
Parathyroid regulation of calcium metabolism
Calcitonin inhibits bone removal by osteoclasts, and promotes bone formation by osteoblasts
Compact Bone Compact bone is the hard material that makes up the shaft of long bones and the outside surfaces of other bones


Spongy Bone Spongy bone consists of thin, irregularly shaped plates called trabeculae, arranged in a latticework network.


Diaphysis The diaphysis, or shaft, is the long tubular portion of long bones. It is composed of compact bone tissue.


Epiphysis The epiphysis (plural, epiphyses) is the expanded end of a long bone.


Metaphysis The metaphysis is the area where the diaphysis meets the epiphysis. It includes the epiphyseal line, a remnant of cartilage from growing bones.

Medullary Cavity The medullary cavity, or marrow cavity, is the open area within the diaphysis. The adipose tissue inside the cavity stores lipids and forms the yellow marrow.

Articular Cartilage Articular cartilage covers the epiphysis where joints occur.


Endosteum

  • The endosteum is the membrane that lines the marrow cavity.




Periosteum The periosteum is the membrane covering the outside of the diaphysis (and epiphyses where articular cartilage is absent). It contains osteoblasts (bone-forming cells), osteoclasts (bone-destroying cells), nerve fibers, and blood and lymphatic vessels. Ligaments and tendons attach to the periosteum.
Long Bones Long bones are some of the longest bones in the body, such as the Femur, Humerus and Tibia but are also some of the smallest including the Metacarpals, Metatarsals and Phalanges. The classification of a long bone includes having a body which is longer than it is wide, with growth plates (epiphysis) at either end, having a hard outer surface of compact bone and a spongy inner known an cancellous bone containing bone marrow. Both ends of the bone are covered in hyaline cartilage to help protect the bone and aid shock absorbtion
Short Bones Short bones are defined as being approximately as wide as they are long and have a primary function of providing support and stability with little movement.
They consist of only a thin layer of compact, hard bone with cancellous bone on the inside along with relatively large amounts of bone marrow.
Flat Bones strong, flat plates of bone with the main function of providing protection to the bodies vital organs and being a base for muscular attachment.
Irregular Bones These are bones which do not fall into any other category, due to their non-uniform shape. Good examples of these are the Vertebrae, Sacrum and Mandible (lower jaw).
Zoomed In Bone
Image:
Tendons Connect muscle to bone
Ligaments Connect bone to bone
Stress Fracture small crack in bone
Compound Fracture the bone exits and is visible through the skin, or a deep wound that exposes the bone through the skin.
Greenstick fracture
incomplete fracture. The broken bone is not completely separated.

Illustration of greenstick fracture
Spiral Frcture
the break spirals around the bone; common in a twisting injury.

Illustration of spiral fracture
Bone is composed of... Collagen and Calcium Salts
Lack of Vitamin D results in ... Rickets ( Bones bow out due to weight)
Long Bone Structure
Image:
Lamellar Bone Lamellar bone has a regular parallel alignment of collagen into sheets (lamellae) and is mechanically strong.
Formation is slower than woven.
Woven Bone Woven bone characterised by haphazard organisation of collagen fibers and is mechanically weak
Woven bone is produced when osteoblasts produce osteoid rapidly which occurs initially in all fetal bones
Forms quickly
Periosteum Membrance that covers bones
Perichondrium Membrance that covers cartilage