CH 6 - Skeletal System Flashcards
What are the components of the skeletal system?
Bones, cartilages, joints, connective tissues
Osteology
The study of bone structure and treatment of bone disorders
What are the functions of the skeletal system?
Support
Store minerals and lipids
Blood cell production
Protection
Leverage
Hematopoiesis (hemopoiesis)
Process of producing blood cells
What are examples of long bones?
Phalanges Metacarpals Metatarsals Femur Tibia Fibula
What are examples of irregular bones?
Vertebrae Pelvic bones Sacrum Sphenoid Ethmoid
What are examples of flat bones?
Ribs
Scapula
Cranial bones
Sternum
What are examples of short bones?
Talus
Carpals
Tarsals
Diaphysis
The shaft of a long bone, made of compact bone
Medullary cavity
Central space within a long bone that contains yellow bone marrow
Epiphysis
The wide ends of a long bone that articulates with other bones, made of spongy bone
*May contain red or yellow bone marrow
Cortical bone (cortex)
A layer of compact bone that surrounds spongy bone
Epiphseal growth plate
Residual hyaline cartilage allowing the bones to grow longer
Epiphyseal line
The ossified bone tissue product once the epiphyseal growth plate is done growing
*Adult height is reached
Describe the structure of a flat bone.
Spongy bone between two layers of cortical bone
Diploë
Spongy bone layer within the cranium
Osseous tissue
A type of supporting connective tissue that contains specialized cells, ground substance, and extracellular protein fibers that form the matrix of bone tissue
What is the organic matrix of bone comprised of?
Collagen fibers and bone cells
What does the organic matrix of bone do?
Provide strength & flexibility
What is the inorganic matrix of bone comprised of?
Calcium salts
- calcium phosphate
- calcium hydroxide
- calcium carbonate
Minerals
- sodium
- magnesium
- fluoride
- phosphorus
What does the inorganic matrix of bone do?
Provide rigidity & compression strength
What are osteocytes?
Amitotic, mature bone cells within a lacuna
What are the functions of osteocytes?
Maintain protein/mineral content of bone matrix
Participate in repairs of damaged bone
Canaliculus
Gap junctions that provide osteocytes with nutrients and oxygen
What do osteoblasts do?
Produce & release proteins/organic components of the organic bone matrix
Promote calcification to produce new bone
What is osteogenesis (bone deposition) and what are the 2 steps involved?
Process of forming bone
- Ossification
- Mineralization
Ossification
Replacing tissue with bone
Calcification
Accumulation of calcium salts in the organic matrix
Mineralization
The addition of calcium and other minerals to osteoid
What are osteoprogenitor (osteogenic) cells?
Connective tissue stem cells that arise from mesenchymal cells
What do osteoprogenitor (osteogenic) cells do?
Where are they found?
Produce & maintain population of osteoblasts
Cell (osteogenic) layer of periosteum, endosteum
What are osteoclasts?
Giant cells with 50+ nuclei, derived from stem cells that produce leukocytes
What do osteoclasts do?
Osteolysis/bone resorption
Secretes acids to dissolve calcium salts, and collagenase to dissolve collagen fibers, in order to destroy/erode bone
*Releases stores minerals into blood
Why do osteoclasts have ruffled borders?
To increase their surface area
Osteon (haversian system)
The basic unit of bone
Central canal (Haversian canal)
Hollow tube in the middle of the osteon that contains an artery, a vein, and a nerve
Perforating canals (volkmann’s canals)
Hollow tubes running perpendicular to the central canal that carry blood vessels and nerves into bone
Concentric lamallae
Thin layers of bone matrix produced by osteoblasts around the central canals of compact bone
*Osteocytes are arranged in concentric lamellae which forms the osteon
Circumferential lamellae
Layers of bone matrix found at the external and internal bone surfaces that enclose the osteons and is covered by the periosteum or endosteum
Interstitial lamellae
Remnants of recycled osteons that fills in the spaces between existing osteons
Trabeculae
A meshwork of supporting thin columns (bony struts) that are covered by the endosteum
*Grows and adapts throughout life
Describe the structure of spongy bone.
Trabeculae allows for stress in many directions.
Spaces between trabeculae are filled with red or yellow bone marrow.
Periosteum
An external membrane that covers all external bone surfaces except parts enclosed in joint capsules or articular cartilage
What are the 2 layers of the periosteum?
Outer, fibrous layer
Inner, cellular layer (osteogenic layer)
*No osteocytes, but all others
Perforating fibers
Thick bundles of collagen fibers of the periosteum that secure it to underlying bone
What are the functions of the periosteum?
Isolate bone from urrounding tissue
Provide entrance for blood vessels & nerves
Participates in bone growth/repair/remodeling
Attachment point for tendons/ligaments