NU545 Unit 6 Part 2 Questions and Answers
Bone matrix (pg 1401 Table 43.1)
Ans: Consists of ground substance, collagen, and other proteins that
take part in bone formation and maintenance.
Collagen Fibers, Proteoglycans, and Glycoproteins. pg 1405 - 1406
Compact bone (cortical bone)
Ans: Makes up approx. 85% of the skeleton; present in every bone;
highly organized, solid, and extremely strong--basic structural unit is
Haversian system.
Spongy bone (cancellous bone)
Ans: Makes up approx. 15% of the skeleton; present in every bone;
-less complex and lacks haversian systems
-the lamellae are not arranged in concentric layers but in plates or bar
termed trabeculae that branch and unite with one another to form an
irregular meshwork
-spaces b/w the trabeculae are filled with red bone marrow.
Periosteum
Ans: All bones are covered with a double-layered connective tissue.
Sharpey Fibers
Ans: Collagenous fibers that penetrate the bone and help hold or attach
tendons and ligaments to the periosteum.
Diaphysis
Ans: Narrow tubular midportion of a long bone.
Metaphysis
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Ans: Broader neck of a long bone.
Epiphysis
Ans: The broad end of a long bone.
Endosteum
Ans: Lines the outer surfaces of both types of marrow cavity.
Flat bones
Ans: (Ribs or scapulae) 2 plates of compact bone which are roughly
parallel to each other; b/w the compact bone plates is a layer of spongy
bone.
Short bones
Ans: (Cuboidal bones) (wrist or ankle) often cuboidal in shape; consist of
spongy bone covered by a thin layer of compact bone.
Irregular bones
Ans: (Vertebrae, mandibles, other facial bones) have various shapes that
include thin and thick segments; thin part of an irregular bone consists
of 2 plates of compact bone with spongy bone b/w the plates; thick part
consists of spongy bone surrounded by later of compact bone.
Physeal closure
Ans: When the skeleton is mature, the epiphyseal plate is replaced by
bone. It unites the metaphysis and epiphysis. It occurs earlier in girls
than boys.
Know Bone Cycle (pg 1409 Fig 43.5)
Ans: Remodeling:
Internal structure of the bone is maintained by remodeling, a three-
phase process in which existing bone is reabsorbed and new bone is laid
down to replace it. Takes 4 to 6 months.
What lab value is associated with muscle mass? pg 1417 - 1418
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