Chapter 7: Bone Tissue, Part II
cells, fibers, and ground substance
components of bone
osteogenic cells, osteoblasts, osteocytes, and osteoclasts
four types of bone cells
stem cells found in the endosteum, periosteum, and central canals
embryonic mesenchymal cells
osteogenic cells arise from...
How often do osteogenic cells multiply?
What do osteogenic cells produce?
bone-forming cells that are nonmitotic
periosteum and endosteum
Osteoblasts form a single layer of cells under ---- and ----.
Osteoblasts synthesize the soft organic matter of the -------.
The soft organic matter of the matrix ---- by mineral deposition.
Stress and fractures stimulate osteoblasts to multiply ------.
reinforce and rebuild
Osteocytes ---- and ---- bone.
hormone secreted by osteoblasts, which stimulates insulin secretion by the pancreas, increases insulin sensitivity in adipocytes, and limits growth of adipose tissue
former osteoblasts that have become trapped in the matrix they have deposited
tiny cavities where osteocytes reside
little channels that connect lacunae
Some osteocytes --- bone matrix while others --- it
bone density; calcium; phosphate ions
Osteocytes contribute to homeostatic mechanism of ---- and ---- and ----
Produce biochemical signals that regulate bone remodeling
What do osteocytes do when stressed?
bone-dissolving cells found on the bone surface
They develop from bone marrow stem cells that give rise to blood cells
How are osteoclasts formed?
How big are osteoclasts?
3 or 4, but might have up to 50
How many nuclei do osteoclasts usually have?
What is the texture of the osteoclast on the side facing the bone surface?
increases surface area and resorption efficiency
What is the purpose of an osteoclast's "ruffled border"?
pits on surface of bone where osteoclasts reside
Osteoclasts are bone-...
Osteoblasts are bone-...
results of osteoclasts and osteoblasts working together
What kind of cells are bone-dissolving?
What kind of cells are bone-depositing?
Matrix of osseous tissue is ---- organic matter by weight
Matrix of osseous tissue is ---- inorganic matter by weight
osteoblasts, collagen, proteins, glycoproteins, glycosaminoglycans, and proteoglycans
What constitutes the organic matter of osseous tissue?
mostly hydroxyapatite, but also calcium carbonate and other minerals
What constitutes the inorganic matter of osseous tissue?
In the polymer-ceramic analogy, --- is the polymer and --- is the ceramic
What portion of bone gives it some degree of flexibility?
soft bones due to deficiency of calcium salts
brittle bone disease, due to lack of protein and collagen
the basic structural unit of compact bone
transverse or diagonal passages along the length of the osteon
skeleton receives about half a liter of blood per minute
openings on the surface of bone tissue that allow blood vessels and nerves to enter the bone
innermost osteocytes near central canal
Which bone cells receive nutrients first?
inner and outer boundaries of dense bone
parallel to bone surface
positioning of circumferential lamellae
remains of old osteons that broke down as bone grew and remodeled itself
spicules, trabeculae, and spaces filled with red bone marrow
What does spongy bone consist of?
slivers of bone
thin plates of bone
yes, but only a few
Does spongy bone have osteons?
all osteocytes of spongy bone are close to bone marrow
Why doesn't spongy bone need central canals?
along bone's lines of stress
Where do trabeculae develop?
soft tissue that occupies marrow cavity of long bone and small spaces among trabeculae in spongy bone
myeloid tissue; in nearly every bone in a child
organ that produces blood cells
In adults, where is red marrow found?
found in adults; fatty; no longer produces blood