Osseus Tissue and Skeletal Structure Flashcards
What is considered appendicular skeleton?
Bones of limbs and bones of limbs that connect to the trunk
Bone is separated from surrounding tissues by what?
Fibrous periosteum
When bones surround another tissue what are the inner bony surfaces lined by?
Cellular endosteum
What enables bone to resist compression?
Calcium phosphate crystals
What do collagen fibers and noncollagenous proteins do for bone?
Provide strength and organic framework for for the formation of mineral crystals
What are the cells of mature bone?
Osteocytes, osteoblasts, osteoprogenitor cells, and osteoclasts
Osteocytes
Bone cells that maintain and monitor protein and mineral content of the surrounding matrix. Calcium release from bone to blood.
Lacunae
Filled with osteocytes they are between layers of calcified matrix
Lamellae
Matrix layers that surround lacunae
Canaliculi
Channels Containing ground substance, interconnect osteocytes situated in adjacent lacunae
What junction interconnects processes of osteocytes and Canaliculi ?
Tight junctions
Osteoblasts
Secrete osteoid and responsible for the production of new bone. If it gets surrounded by matrix, it becomes an osteocyte
Osteoprogenitor cells
Found in inner most periosteum and endosteum lining the medullary cavities, they can differentiate into osteoblasts.
Osteoclasts
Found at sites where bone is removed and secrete acid which perform osteolysis.
Osteolysis
Erosion of calcium and phosphate into the blood due to an exocytosis of lysosomes
What are the two types of osseus tissue?
Compact bone and Spongy bone
Osteon
Basic functional unit of compact bone that includes rings of osteocytes around the central canal
Central canal
Canal that contains blood vessels that supply the osteon. Haversian canal
What is the difference between central canals and perforating canals?
Central canals are parallel to bone surface. Perforating canals are perpendicular to the cell surface
Preforating canal
Volkmanns canal. Deliver blood deeper into the bone and service the medullary cavity
Concentric Lamellae
Aligned parallel to the long axis of the bone. Resembles a bulls eye target around central canal
Interstitial Lamellae
Fill in the spaces between the osteons in compact bone
Circumferential Lamellae
Occur at the inner and external surfaces of the bone.
What is the difference between spongy bone and compact bone?
Arrangement of spongy bone into trabeculae
Trabeculae
Found in spongy bone. Parallel thick branching plates giving spongy bone strength
What does spongy bone do for muscles and skeleton?
Reduces the weight of skeleton and makes it easier for muscles to move the bones
Periosteum
Covers superficial layer of compact bone
Where is a periosteum not complete?
Within a joint
Epiphyses
Ends of bone
Cortex
Surrounds the medullary cavity
Diaphysis
Shaft of bone
Metaphysis
Where the diaphysis is connected to the epiphysis
Fracture
When a bone breaks from impact to the side
Which bone type is more capable of handling stresses from different directions?
Spongy
Perforating fibers
Collagen fibers incorporated into bone tissue from tendons and superficial periosteum
Endosteum
Lines medullary cavity and contains osteoprogenitor cells, covers trabeculae, lines canals. Most active during growth of bone, repair
Ossification
Process of replacing other tissues with bone
What are the two major forms of ossification?
Intramembranous ossification and endochondral ossification
Intramembranous ossification
Bone develops from Mesenchyme or fibrous connective tissue. Occurs in formation of bones such as the clavicle, mandible, and flat bones of the face and skull
Endochondral ossification
Bone replaces an existing cartilage model. Bones of limbs and those that bear weight develop by this method
Epiphyseal closure
Rate of epiphyseal cartilage enlargement slows and osteoblasts activity accelerates. Epiphyseal cartilage gets narrow until it disappears
Epiphyseal line
Line that occurs after epiphyseal growth has ended
Articular cartilage
Thin cap of exposed cartilage that prevents damaging bone to bone contact
What mechanism of growth enlarges the diameter of bone?
Appositional Growth
What are the four major blood vessels in a typical long bone?
Nutrient artery and vein, metaphyseal vessels, epiphyseal vessels, and periosteal vessels
Metaphyseal vessels
Supply blood to inner surface of epiphyseal cartilage, where bone is replacing cartilage
Epiphyseal vessels
Uses foramina to supply osseous tissue and medullary cavities
Periosteal vessels
Provide blood to the superficial osteons of the shaft
Osteopenia
Inadequate ossification when aging
What is considered the axial skeleton?
Bones of the skull, vertebral column, sternum, ribs
