cartilage and bone structure and function. bones
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Cartilage and BoneStructure and Function
Bones
Bone Characteristics
Vascular (has own blood supply)Regenerates well Contains calcium and hydroxyapatiteForms mostly after birthIs not flexible
Bone Cells
Osteoblast (makes bone)Osteocyte (mature bone cell)Osteoclast (reabsorbs bone)
Formation of Endochondral Bone
Hyaline cartilage develops in the general shape of the future bone.
Periosteum forms on the outside of the developing bone.
Osteoblasts deposit bony tissue in place of disintegrating cartilage.
Types of Ossification
Primarystarts in diaphysis from cartilage
Secondarystarts in epiphysis from cartilage
Types of Bones
Long BonesArms and legs
Sesamoid BonesDevelop inside tendons and near joints
Flat BonesSkull bones and scapula
Irregular Bonesvertebrae
Cartilage
What are the three types of cartilage? Hyaline cartilage (most of the joints) Fibrocartilage (vertebral discs, pubic symphysis) Elastic cartilage (ears)
Where in the body can each of these three types of cartilage be found?
What type of cartilage does an embryonic skeleton have? Hyaline
Cartilage Characteristics
Avascular (no blood supply)Does not regenerate wellContains no calcium or hydroxyapatiteBegins conversion to bone before birthIs flexible
Joint Disorders and Joint Injuries
Structure of joints makes them prone to traumatic stress Function of joints makes them subject to friction and wear Affected by inflammatory and degenerative processes Sprains – ligaments reinforcing a joint are stretched or torn Dislocation – occurs when the bones of a joint are forced out
of alignment Torn cartilage – common injury to meniscus of knee joint
Inflammatory and Degenerative Conditions
Bursitis – inflammation of a bursa due to injury or friction Tendonitis – inflammation of a tendon sheath Arthritis – describes over 100 kinds of joint-damaging
diseases Osteoarthritis – most common type – “wear and tear” arthritis Rheumatoid arthritis – a chronic inflammatory disorder Gouty arthritis (gout) – uric acid build-up causes pain in joints
Lyme disease – inflammatory disease often resulting in joint pain; Lyme disease is caused by a bacterium and is transmitted to humans by the bite of infected blacklegged ticks. Typical symptoms include fever, headache, fatigue, and skin rash. If left untreated, infection can spread to joints, the heart, and the nervous system.
Osteoporosis: loss of minerals
Figure 6.15
Normal Bone
Osteoporosis
Stages of Healing a Fracture
Figure 6.14
Blood escapes
Fibrous callous
Spongy Bone callous
Osteoclasts remove excess bone
Categories of Fractures
Simple: Skin is not broken Compound: Bone sticks out through skin, often
gets infected
Complete: Both sides of diaphysis broken through
Incomplete: One side of diaphysis is broken
Stress: Just a crack in the surface
Types of Fractures
ComminutedCompressionSpiralEpiphysealDepressedGreenstick
Table 6.1
Table 6.1
Table 6.1
Table 6.1
Table 6.1
Table 6.1
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