Bone Structure and Functions Quiz

Bone Structure and Functions

• Bones protect internal organs, for example: the skull protects the brain, and the vertebral column protects the spinal cord.
• Bones store and release fat (yellow bone marrow).
• Bones produce blood cells (red bone marrow).
• Bones store and release minerals, including calcium and phosphorus.
• Bones facilitate movement by providing attachment points for muscles.
• Bones support the body, acting as a scaffolding.

Bone Marrow

• Bone marrow is connective tissue found inside most bones.
• Yellow bone marrow stores fat (adipocytes) in the form of triglycerides.
• Red bone marrow forms blood cells (hematopoiesis).
• Red bone marrow produces red blood cells, white blood cells, and platelets.

Parts of a Long Bone

• Epiphysis: The end of a long bone that articulates with another bone (forms a joint).
• Articular cartilage: Hyaline cartilage covering the epiphysis.
• Metaphysis: The location of the epiphyseal plate (growth plate) within the intermediate area of a long bone.
• Diaphysis: The shaft of the long bone.
• Periosteum: The tough, vascular covering of the bone tissue.
• Medullary cavity: A hollow chamber located within the diaphysis containing bone marrow tissue.

Bone Classification

• Long bones: Cylinder-like and longer than they are wide (e.g., femur, tibia, fibula, humerus, ulna, radius, metacarpals, and phalanges).
• Short bones: Cube-like, with similar dimensions in length, width, and thickness (e.g., carpals and tarsals).
• Flat bones: Thin and curved (e.g., sternum, ribs, scapulae, and cranial bones).
• Irregular bones: Complex shape (e.g., vertebrae and facial bones).
• Sesamoid bones: Small, round bones embedded within tendons (e.g., patella).

Compact vs. Spongy Bone

• Compact bone: Dense, tightly packed tissue with a continuous extracellular matrix. Found in the diaphysis. 
• Spongy bone: Irregular, thin bony plates with projections; highly developed to resist compressive forces, reducing bone weight. Found in the epiphysis.

Bone Matrix

• Osseous tissue (bone tissue) is connective tissue that supports the cells, called osteocytes, providing both structure and flexibility.
• The matrix is composed of collagen fibers (1/3) and calcium and phosphate salts (2/3).
• Collagen provides flexibility and framework for bone formation.
• Calcium and phosphate salts provide hardness and strength to bone.

Bone Cells

• Osteogenic cells: Stem cells that differentiate into osteoblasts as needed.
• Osteoblasts: Build bone matrix by secreting the collagen matrix.
• Osteocytes: Mature bone cells that maintain bone tissue.
• Osteoclasts: Resorb old bone tissue.

Paget's Disease

• A disorder of bone remodeling process.
• Patients usually over 40 years old.
• Overactive osteoclasts cause bones to be prone to fractures.
• Symptoms include bone deformities, pain, and frequent fractures.

Bone Fractures

• Open Fractures: The fractured bone breaks through the skin.
• Closed Fractures: The fractured bone is misaligned but remains within the skin.
• Reduction: Manipulating the bone back to its correct alignment.
• Open Reduction: Surgical procedure to reduce the bone.
• Closed Reduction: Non-surgical procedure to reduce the bone.

Fracture Repair

• Direct bone healing involves direct bone-to-bone contact.
• Indirect bone healing involves the formation of cartilaginous patches between the broken bones before regeneration begins.