SKELETAL SYSTEM

• Osteoblasts (bone builders) - produces new bone

  Bone Calcification

  Periosteum & Endosteum
• Osteocytes

  • Mature bone cells
  • activated in fractures
• Osteoclasts (bone eaters)

  Bone Resorption , increase the size of tha marrow cavity

  Endosteum
• BONE RESORPTION - Digestion of bone matrix for normal growth, development, repair and maintenance
• Epiphysis – The rounded end of a long bone where it meets another bone to form a joint.
• o Diaphysis – The long, straight part of a bone that connects the ends. It's like the bone's main body.
• Articular cartilage – It's the smooth covering at the end of bones that helps them move smoothly and without pain in a joint.
• Compact Bone – Hard, dense outer layer providing strength and protection to bones.
• Spongy Bone – Lightweight, porous inner structure with trabeculae supporting bone strength and housing bone marrow for blood cell production.
• Periosteum – Dense connective tissue covering the outer surface of bones, involved in bone nourishment, repair, and tendon/ligament attachment.
• Endosteum – Thin membrane lining the inner surface of bones, particularly the marrow cavity, responsible for bone remodeling, repair, and mineral exchange with the bloodstream.
• 1.Long Bones (humerus)

  2. Short Bone (trapezoid)

  3. Flat Bone (sternum)

  4. Irregular Bone (vertebra)

  5. Sesamold Bone (patella)
• OSTEOGENESIS - It refers to the formation of bone by osteoblast
• Appositional Growth

  • It refers to the formation of new bone on the surface of existing bone
  • Increase bone diameter
• Endochondral Growth

  - It refers to the growth of cartilage in the epiphyseal plate and its eventual replacement by bone.

  • increase in bone length
• Resorption – during which osteoclasts digest old bone.
• Reversal – when mononuclear cells appear on the bone surface.
• Formation – when osteoblasts lay down new bone until the resorbed bone is completely replaced.
• BONE REPAIR - A process in which a bone repairs itself following a bone fracture.

  • When a bone is broken, a clot forms in the damaged area.
  • Callus forms, the zone of tissue repair between the two bone fragments.
• Calcium moves into bone as osteoblasts build new bone.

  Calcium move out of bone as osteoclasts break down bone.
• Spina Bifida

  • Birth defect
  • Improper formation of the vertebra
• Osteogenesis Imperfecta (Brittle Bonse Disease – children)

  • Skeleton does not ossify properly
  • Often characterized by a blue coloration of the white sclera of the eye
• Achondroplasia

  A form of short

  limbed "dwarfism".

  Achondroplasia literally means “without cartilage formation”.
• • Osteoporosis (Brittle Bonse Disease – adults) -Generalized or localized deficiency of bone matrix o Bones become lighter and fracture easier
• Osteomalacia (Bone Softening – Adults)

  • Reverse of OSTEOPOROSIS o Bones are inadequately mineralized causing softened, weakened bones.
• Rickets (Bone Softening – Children) o Bones of children are inadequately mineralized causing softened, weakened bones. o Bowed legs and deformities of the pelvis, skull, and rib cage are common.
• Paget Disease (Osteitis Deformans) o Chronic disorder that can result in enlarged and misshapen bones
• Scoliosis - Lateral curvature of the central part of the spine. - The condition is brought on by: 1. congenitally malformed vertebra 2. chronic sciatica 3. paralysis of muscles on one side of the backbone 4. poor posture
• Arthritis - It literally means “joint inflammation”, however some forms could affect the skin and internal organs. - It is marked by pain, stiffness and swelling of the affected joint. - It may include one or several joints
• Osteoarthritis - Commonly known as “wear and tear” arthritis - A degenerative joint disease in which the cartilage that covers the ends of the bones in the joint deteriorates
• Rheumatoid arthritis - An active chronic inflammatory autoimmune disease affecting synovial membrane.
• Gouty arthritis - A disease associated with an inborn error of uric acid metabolism.