Osteology Flashcards
What are the four tissues of the human body?
epithelial, muscle, neural & 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 & 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 & carbonate ions
What is the most frequently described deposit in bone?
hydroxyapatite
Bone is also the repository for what additional ions?
sodium, magnesium, fluoride, lead, strontium & 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 which 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 & 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 & greater wing of the sphenoid
Which bones of the splanchnocranium are formed by intramembranous ossification?
the nasal, palatine, vomer, lacrimal, zygomatic, maxilla & 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 splanchnocranium 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 & occipital bones
Which skull bones are ossified by both endochondral and intramembranous ossification?
the mandible, sphenoid, temporal & occipital bones
What 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?
primary centers of ossification appear before birth 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 and spongy, cancellous or trabecullar bone
What is the name given to the bone below an articulating surface?
subchondral bone
What is the name of the outer fibro-cellular 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?
gender variation (sexual dimorphism), ontogenetic variation (growth or age variation), geographic or population-based variation (ethnic variation) and idiosyncratic variation (individual variation)
What is the name give to the type of variation that is unique to an individual?
idiosyncratic variation
What are the six more commonly used classifications of normal bone?
long bones, short bones, flat bones, irregular bones, paranasal sinus or pneumatic bones and sesamoid bones
What are the classifications given to abnormal bone stressed in Spinal II?
heterotopic and accessory bone
What is the name given to bone formed in a non-bone location?
heterotopic bone
What is the name given to bone formed from existing bone?
accessory bone
What is the characteristic feature of a long bone?
it is longer than it is across (length greater than breadth)
What are the names given to the parts of a long bone?
the diaphysis (shaft) and typically two epiphyses (extremities)
What are examples of long bones?
humerus, radius, ulna, femur, tibia and fibula
What is the primary characteristic of short bones?
they are essentially cuboidal
What are examples of short bones?
most of the bones of the carpus and tarsus
What are flat bones?
a thin layer of spongy bone is sandwiched between two layers of compact bone
What are examples of flat bones?
the parietal bone and sternum