What is bone?
Second hardest substance within an animals body (1st being the enamel layer of teeth) It is composed of cells embedded in a matrix (background)
whats Matrix?
Is made up of collagen fibers embedded in a protein and polysacharides
-Hardens when deposits of calcium and phosphates are laid down.
ossification
refers to the process by which new bone tissue is formed during skeletal development or bone healing. This process involves the deposition of minerals, primarily calcium and phosphate, into a matrix of collagen fibers, resulting in the hardening and strengthening of bone.
Intramembranous bone formation
This type of ossification occurs within a connective tissue membrane. It is responsible for the formation of flat bones, such as those in the skull and certain parts of the face. During intramembranous ossification, mesenchymal cells differentiate into osteoblasts, which then secrete osteoid tissue that mineralizes to form bone.
occurs in certain skull bones, bone forms in the fibrous tissue membranes that cover the brain in the developing fetus.
⦿ Intramembranous ossification: The flat bones of the skull are formed. the osteoblasts lay down bone between two layers of fibrous connective tissue. there is no cartilage template.
Osteoblasts: Osteoblasts are the cells that form new bones and grow and heal existing bones.
Endochondral Bone Formation
Endochondral ossification involves the replacement of cartilage with bone tissue. This process is responsible for the formation of most long bones in the body, as well as some irregular bones. During endochondral ossification, a cartilage model of the bone is first formed, which is gradually replaced by bone tissue as osteoblasts deposit minerals into the cartilage matrix.⦿ Primary growth center: bones develop in the diaphyses - cartilage rod -
⦿ Cartilage is removed as bone is created. Secondary growth centers: develop in the epithyses of bones.
⦿ Epiphyseal plates: cartilage is located between the diaphysis and the epiphysis of long bones, sites where new bone develops to allow long bones to lengthen.
⦿ Osteoblasts replace cartilage with bone on the diaphyseal surface of the plate, when the bone has reached its full size, the epiphyseal plates completely ossify.
Osteoblasts
Osteoblasts are essential cells involved in bone formation and remodeling processes in the body. They originate from mesenchymal stem cells and are primarily found in the outer layer of bone tissue, known as the periosteum, as well as in the endosteum, which lines the inner surfaces of bones.
When bone formation is required, osteoblasts become activated and begin synthesizing and secreting osteoid, which is a matrix rich in collagen fibers. This osteoid serves as the framework or scaffold for new bone tissue formation. Over time, minerals such as calcium and phosphate are deposited onto the collagen fibers within the osteoid matrix, a process known as mineralization or calcification. This results in the hardening of the osteoid into mature bone tissue.
In addition to producing osteoid, osteoblasts also play a role in regulating the mineralization process by secreting proteins and enzymes that control the deposition of minerals. These cells are also involved in the synthesis and release of various growth factors and signaling molecules that influence the activity of other bone cells, such as osteoclasts (cells responsible for bone resorption) and osteocytes (mature bone cells embedded within the bone matrix).
As bone formation progresses, some osteoblasts become entrapped within the mineralized bone matrix and differentiate into osteocytes. These osteocytes maintain communication with neighboring cells and play a role in regulating bone metabolism and responding to mechanical stress.
Fracture Types
Complete Fracture, Incomplete Fracture, Open Fracture (Compound Fracture), Closed Fracture, Transverse Fracture, Oblique Fracture, Spiral Fracture, Greenstick Fracture, Comminuted Fracture, Avulsion Fracture, Pathological Fracture, Impacted Fracture, Linear Fracture, Compression Fracture, Segmental Fracture, Hairline Fracture, Stress Fracture, Depressed Fracture, Displaced Fracture, Non-displaced Fracture, Fatigue Fracture, Tension Fracture, Shear Fracture, Torus Fracture (Buckle Fracture).
Complete Fracture
Incomplete Fracture
Open Fracture (Compound Fracture)
Closed Fracture
Transverse Fracture
Oblique Fracture
Spiral Fracture
Greenstick Fracture
Comminuted Fracture
Avulsion Fracture
Pathological Fracture
Impacted Fracture
Linear Fracture
Compression Fracture
Segmental Fracture
Hairline Fracture
Stress Fracture