Osseous Tissue (Bone Tissue). Classification of Bone by Tissue Type Two basic types of Tissue 1....
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Transcript of Osseous Tissue (Bone Tissue). Classification of Bone by Tissue Type Two basic types of Tissue 1....
Classification of Bone by Tissue Type
• Two basic types of Tissue1. Compact bone
• Homogeneous• Looks “smooth”
2. Spongy bone• Small needle-like
pieces of bone• Many open spaces
(like sponge)• Keep bones light
Figure 5.2b
Review:
• Bone is a type of connective tissue2 Parts:
1. Cells (living)
2. Matrix (nonliving substance released by cells)
A. FiberB. Ground Substance
1. Cells• Osteocytes— mature bone cells• Osteoblasts— bone-forming cells (germ cells or “bud” cells)• Osteoclasts —bone-destroying cells (“breakers”)
A. primarily collagen fibersflexibility tensile strength (the strength to endure stretching
forces) B. calcium salts (hardness)
contain calcium and phosphorus great compressional strength (the strength to endure
squeezing forces)
2. Matrix
Bone Remodeling
constant balance of bone deposit and removal that occurs throughout your life
bone deposit occurs at a greater rate when bone is injured
bone resorption allows calcium of degraded bone matrix to move into the blood. About 10% of bone is
replaced every year in an adult skeleton
Control of Remodeling
Hormonal
– Rising blood Ca2+ levels trigger the thyroid to release calcitonin
– Calcitonin stimulates calcium salt deposit in bone
– Falling blood Ca2+ levels signal the parathyroid glands to release Parathyroid hormone (PTH)
– PTH signals osteoclasts to degrade bone matrix and release Ca2+ into the blood
boneformation
bonereabsorption
osteoblasts osteoclastsCalcitonin (CT)
from thyroidParathyroidhormone (PTH)
from parathyroid
Hormonal effects
bone
formation
bone
reabsorption
osteoblasts osteoclasts
Stress effects
Stress increases bone density
http://www.youtube.com/watch?v=yFJ4iswRiu4&feature=related