Chapter 6: Bone and Skeletal Tissues Flashcards
Skeletal cartilages
associated w/ bones, no blood vessels/nerves, surrounded by perichondrium (dense irregular connective tissue) that resists outward expansion
Hyaline cartilage
provides support, flexibility, and resilience
most abundant skeletal cartilage
contains very fine collagen fibers
Articular
covers ends of long bones
Costal
connects ribs to sternum
Respiratory
makes up larynx and reinforces air passage
Nasal
supports the base
Elastic Cartilage
similiar to hyaline but contains elastin fibers
found in external ear and epiglottis
Fibrocartilage
highly compressed with great tensile strength
contains collagen fibers
found in menisci of knee and intervertebral discs
Appositional
cells in perichondrium secrete matrix against external face of existing cartilage
Interstitial
lacunae-bound chondrocytes inside the cartilage divide and secrete new matrix, expanding the cartilage from within
Calcification
occurs during normal bone growth, during old age
Axial skeleton
bones of skull, vertebral column, and rib cage
Appendicular skeleton
bones of the upper and lower limbs, shoulder, and hip
Long Bones
longer than they are wide
Flat bones
thin, flattened and a bit curved (sternum, most skull bones)
Irregular bones
bones with complicated shapes (vertebrae and pelvic bones)
Support
form the frameworks that supports body and cradles soft organs
Protection
provide protective case for the brain, spinal cord, and vital organs
Movement
provide levers for muscles
mineral storage
reservoir for minerals, especially calcium and phosphorus
blood cell formation
hematopoiesis occurs within the red marrow cavities of bones
Bone markings
bulges, depressions, and holes that serves as
sites of attachment for muscles, ligaments, and tendons
joint surfaces
conduits for blood vessels and nerves
Projections
sites of joints between bones
Projection Head
bony expansion carried on a narrow neck
Projection Facet
smooth, nearly flat articular surface
Projection Condyle
rounded articular projection
Projection Ramus
armlike bar of bone
Compact bone
dense outer layer
spongy bone
honeycomb of trabeculae filled with red or yellow bone marrow
Diaphysis
tubular shaft that forms the axis of long bones, composed of compact bone, yellow bone marrow is contained in the medullary cavity (fat)
Epiphyses
expand ends of long bones, exterior is compact bone and the interior spongy bone, joint surface is covered with articular (hyaline) cartilage, epiphyseal line separates the diaphysis from epiphyses
Short, Irregular, Flat bones
thin plates of periosteum-covered compact bone on the outside with endosteum-covered spongy bone on the inside
no diaphysis or epiphyses
contain bone marrow btw the trabeculae
Periosteum
double-layered protective membrane
outer fibrous layer
dense irregular connective tissue
inner osteogenic layer
composed of osteoblasts and osteoclasts
richly supplied w/ nerve fibers, blood, lymphatic vessels, which enter the bone via nutrient foramina
attached to bone by sharpey’s fibers
endosteum
delicate membrane covering internal surfaces of bone
Haversian system or osteon
the structural unit of compact bone
Lamella
weight-bearing, column-like matrix tubes composed mainly of collagen and calcified matrix
Haversian or central canal
central channel containing blood vessels and nerves
Volkmann’s canals
channels lying at right angles to the central canal, connecting blood and nerve supply of the periosteum to that of the Haversian canal
Osteocytes
mature bone cells
Lacunae
small cavities in bone that contain osteocytes
Canaliculi
hairlike canals that connect lacunae to each other and the central canal
Osteoblasts
bone matrix-forming cells
Osteoclasts
large cells that resorb bone matrix
Osteoid
unmineralized bone matrix composed of ground substance and collagen
Hydroxyapatites
bone matrix, or mineral salts
65% of bone by mass, mainly crystals of calcium phosphates, responsible for bone hardness and its resistance to compression
osteogenesis (ossification)
the process of bone tissue formation which leads to the formation of the bony skeleton in embryos, bone growth occurs until early adulthood, bone thickening, remodeling and repair
Intramembranus ossification
bone develops from a fibrous membrane (skull bones and clavicles)
Endochondrol ossification
bone forms by replacing hyaline cartilage
Growth zone
cartilage cells undergo mitosis pushing the epiphysis away from the diaphysis
Transformation zone
older cells enlarge, the matrix becomes calcified, cartilage cells die, and the old matrix begins to deteriorate
Osteogenic zone
new bone formation occurs
Alkaline phosphatase
essential for mineralization of bone
Osteoid seam
unmineralized band of bone matrix
Calcification front
transition zone between the osteoid seam and the older mineralized bone
resorption bays
grooves formed by osteoclasts as they break down bone matrix
lysosomal enzymes
digest organic matrix
acids
convert calcium salts into soluble forms
hormonal mechanism
maintains calcium homeostasis in the blood
mechanical and gravitational force
acting on the skeleton
Wolff’s law
a bone grows or remodels in response to the forces or demands placed upon it
Nondisplaced
bone ends retain their normal position
Displaced
bones ends are out of normal alignment
Complete
bone is broken all the way through
incomplete
bone is not broken all the way through
Linear
the fracture is parallel to the long axis of the bone
Transverse
the fracture is perpendicular to the long axis of the bone
compound (clean)
bone ends penetrate the skin
simple (closed)
bone ends do not penetrate the skin
Hematoma formation
torn blood vessels hemorrhage,
a mass of clotted blood (hematoma) forms at the fracture site
site becomes swollen, painful, and inflamed
Fibrocartilaginous callus
granulation tissue (soft callus) forms within few days, capillaries grow into the tissue and phagocytic cells begin cleaning debris, fibroblasts secrete collagen fibers that connect broken bone ends, osteoblasts begin forming spongy bone
Bony callus formation
new bone trabeculae appear in fibrocartilaginous callus, fibrocartilaginous callus converts into a bony (hard) callus, bone callus begins 3-4 weeks after injury and continues until firm union if formed 2-3 months later
bone remodeling
excess material on the bone shaft exterior and in the medullary canal is removed, compact bone laid down to reconstruct shaft walls
Osteomalacia (adults)
bones are inadequately mineralized causing softened, weakened bones, main symptom is pain when weight is put on the affected bone, caused by insufficient calcium in the diet or by vitamin D deficiency
Rickets (children)
bones of children are inadequately mineralized causing softened, weakened bones
bowed legs and deformities of pelvis, skull and rib cage are common
caused by insufficient calcium in the diet or by vitamin D deficiency
Osteoporosis
group of diseases in which bone reabsorption is greater than bone deposition
spongy bone of the spine is most vulnerable
occurs most often in postmenopausal women
