Cells, Matrix, Ossification, Bone Density, Bone Variation Flashcards
What are the four basic tissues of the human body?
epithelial, muscle, neural, and connective tissues
What is osteology?
the study of bone
What are the three primary cell types of bone?
osteoblasts, osteocytes, and osteoclasts
What is the function of each type of bone cell?
osteoblast - form bone; osteocyte - maintain or nurture bone; osteoclast - remodel bone
What are the bone cells embedded in?
an amorphous matrix consisting of ground substance, protein fibers, and various minerals
What is the primary constituent of the ground substance?
glycosaminoglycans
What types of glycosaminoglycans predominate in bone?
chondroitin sulfates, keratin sulfates, and hyaluronic acid
What is the principal type of protein fiber in bone?
collagen type I
What are the primary constituents of the bone mineral?
calcium, phosphate, citrate, and carbonate ions
What is the most frequently described deposit in bone?
hydroxyapatite
Bone is also the respository for what additional ions?
sodium, magnesium, fluoride, lead, strontium, and radium
What is Wolff’s Law as it pertains to bone?
living tissue will respond to stressors; bone is formed or absorbed in response to stress
What are the three responses of bone that allow it to be described as “living?”
it has the ability to heal, to remodel under stressors, and to age
What is bone the embryological derivative of?
mesenchyme or cartilage
What is the name given to the pattern of ossification in mesenchyme?
intramembranous ossification
What is the timing for the appearance of intramembranous ossification?
from the second to third month in utero
What bones are derived from intramembranous ossification?
the nasal, palatine, vomer, lacrimal, zygomatic, maxilla, frontal, parietal, most of the mandible and clavicle, the squama of the temporal and occipital bones, and the greater wing of the sphenoid
Which bones of the neurocranium are formed by intramembranous ossification?
the frontal, parietal, squama of the temporal and occipital bones, and greater wing of the sphenoid
Which bones of the facial skeleton are formed by intramembranous ossification?
the nasal, palatine, vomer, lacrimal, zygomatic, maxilla, and part of the mandible
What is the name given to the pattern of ossification in cartilage?
endochondral ossification
What is the timing for the appearance of ossification in cartilage?
from the second to fifth month in utero
What part of the skull is derived from endochondral ossification?
chondrocranium
What bones are formed from the chondrocranium?
the inferior nasal concha, ethmoid, and the remainder of the mandible, sphenoid, temporal, and occipital bones
Which bones of the facial skeleton are derived from cartilage?
the inferior nasal concha and part of the mandible
Which bones of the neurocranium are derived from cartilage?
the ethmoid and parts of the sphenoid, temporal, and occipital bones
Which skull bones are ossified by both endochondral and intramembranous ossification?
the mandible, sphenoid, temporal, and occipital bones
Which bone of the appendicular skeleton is formed by both endochondral and intramembranous ossification?
the clavicle
What are the names given to the centers of ossification based on time of appearance?
the primary centers of ossification appear before birth; the secondary centers of ossification appear after birth
Mature bone is described as being composed of what areas based on bone density?
cortical or compact bone & spongy, cancellous, or trabecular bone
What is the name given to the bone below an articulating surface?
subchondral bone
What is the name of the outer fibro-celluar covering of bone?
the periosteum
What is the name given to the fibro-cellular lining of bone?
the endosteum
What are the primary sources of variation observed in bone?
sexual dimorphism (gender variation), ontogenetic variation (growth or age variation), geographic or population-based variation (ethnic variation), and idiosyncratic variation (individual variation)
Differences in the number or morphology of vertebrae within the population based on male and female variation is identified as which type of variation?
sexual dimorphism or gender variation
Differences in the number or morphology of vertebrae within the population based on age or developmental variation is identified as which type of variation?
ontogenetic variation
Differences in the number or morphology of vertebrae within the population based on ethnicity or locational variation is identified as which type of variation?
geographic variation or population-based variation
Differences in the number or morphology of vertebrae withing the population based on the uniqueness between individuals is identified as which type of variation?
idiosyncratic variation
