skeletal

To list and describe the functions of cell types and hormones in bone formation and matrix maintenance.

Terms Involved:
- Matrix: The intercellular substance in which the cells are embedded.
- Osteoblast: Cells responsible for bone formation. They synthesize and secrete the bone matrix and facilitate mineralization.
- Ossification: The process during which bone tissue is formed.
- Calcium and Phosphate: Essential minerals for bone health, contributing to its strength and rigidity.
- Osteocyte: Mature bone cells that reside in bone matrix.
- Lacunae: Small cavities in bone that house osteocytes.
- Canaliculi: Microscopic channels that connect lacunae and allow for nutrient and waste transport between osteocytes.
- Epiphyseal Cartilage: Cartilage located at the ends of long bones that facilitates growth and development.
Hormones Involved in Bone Formation:
- Parathyroid Hormone (PTH): Increases serum calcium levels by stimulating osteoclast activity.
- Calcitonin: Decreases serum calcium levels by inhibiting osteoclast activity.
Types of Bone Development:
- Endochondrial ossification (long bones).
- Intramembranous ossification (flat bones).

Describe classifications of bone structure and the main parts and functions of bones:
- Axial Skeleton: Comprises the skull, hyoid bone, vertebral column, ribs, and sternum.
- Appendicular Skeleton: Comprises limbs attached to the axial skeleton.
Discuss different fracture types and the healing process, particularly focusing on epiphyseal plate fractures.

Osteoclasts: Break down bone tissue during remodeling.
Osteoblasts: Form new bone tissue during repair and maintenance.
Osteocytes: Retain the activity of osteoblasts, contributing to bone health.

Protection: Shields vital organs (e.g., skull protects the brain).
Support: Maintains body structure, providing a framework for soft tissues.
Leverage: Bones act as levers, facilitating movement through muscle attachment.
Mineral Storage: Bones store minerals, primarily calcium and phosphorus.
Blood Formation: Red bone marrow within bones is responsible for erythropoiesis (red blood cell production).
Nutrient Storage: Yellow bone marrow stores fats, which can be utilized during starvation.

Calcium Homeostasis: Critical for functions such as muscle contraction, nerve transmission, and blood coagulation.
- Primary Hormones:
- PTH: Increases serum calcium levels by promoting bone resorption.
- Calcitriol (Vitamin D): Enhances calcium absorption in the intestines and mobilizes calcium from bone.
- Calcitonin: Reduces serum calcium by promoting bone formation and reducing resorption.
Calcium to Phosphorus Ratio: Normal ratio approximately 2:1 in the body.

Rickets: Caused by vitamin D deficiency, leading to poor mineralization of bone, resulting in deformities.

Compact Bone: Dense and forms the outer layer of bone.
Cancellous Bone: Spongy and lightweight; contains bone marrow.
Epiphysis: The rounded end of a long bone, which forms joints with adjacent bones.
Diaphysis: The shaft of a long bone, providing major support.
Metaphysis: Section between the diaphysis and epiphysis; contains growth plates.

Articular Surfaces: Areas where bones meet to form joints:
- Condyle: A round, large articular surface.
- Head: A spherical articular surface at the proximal end of a long bone.
- Facet: A flat surface for articulation.
Processes: Protrusions from the bone, acting as attachment points for ligaments and tendons.
- Examples: Crest, Trochanter, Spine, Tuberosity.
Foramen: Openings that allow nerves and blood vessels to pass through bones.
Fossa: Depressed or sunken area on bone surfaces.

Functions of the Skull: Protects the brain, houses sense organs, and provides attachment for facial structures including teeth and larynx.
Sinuses: Air-filled spaces that can serve as resonating chambers and can be sites for potential infections.
Variations in Skull Types: Type:
- Dolichocephalic: Long, narrow skull.
- Mesaticephalic: Medium-sized skull.
- Brachycephalic: Short, broad skull.

Epidurals: Typically administered in the lumbosacral space for pain relief and surgery.
IVDD (Intervertebral Disc Disease): Condition resulting from injury to disc material between vertebrae leading to impingement on nerves.

Sternum: Comprised of 7 bones (manubrium, body, xiphoid).
Ribs: Articulate with thoracic vertebrae, comprising true (direct attachment to sternum), false (via cartilaginous material), and floating ribs (no attachment).

Components of the Appendicular Skeleton:
- Pectoral Girdle (Forelimbs): Impacted by muscular attachment rather than bony.
- Pelvic Girdle (Hindlimbs): Strong base that supports the hindquarters; includes ilium, ischium, and pubis.

Luxating Patellas: A common condition in small dogs where the kneecap dislocates.
Hip Dysplasia: A heritable condition leading to joint instability and pain due to abnormal hip development.

Categories of Fractures:
- Transverse: Fracture line is horizontal.
- Oblique: Angled fracture line.
- Fissure: A thin crack in the bone.
- Comminuted: Bone is shattered into multiple fragments.
- Spiral: Fractures occurring due to twisting forces.
- Avulsion: A piece of bone is pulled off by a tendon or ligament.
- Physeal: Fracture involving the growth plate.

Type I-IV: Different types of fractures that involve the growth plate, outlining prognosis and necessary interventions for repair.

Involves alignment, immobilization, and the progression from hematoma formation to the remodeling phase. Non-union can occur due to misalignment, poor fixation, or infection.