Chapter 6 Bones and The Skeletal System

Growth of the bone is by cartilage with endochondral

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ilage grows by both appositional & interstitial growth Bones increase in length by interstitial growth of epiphyseal plate Bones increase in width by appositional growth growing brain or starting to walk athletes or history of manual labor have greater density & mass of bone osteoblasts lay down matrix in layers parallel to the outer surface & osteoclasts dissolve bone on inner surface if one process outpaces the other, bone deformities occur (osteitis deformans) Achondroplastic Dwarfism Short stature but normal sized head and trunk Result of spontaneous mutation when DNA is replicated long bones of the limbs stop growing in childhood but other bones unaffected Pituitary dwarf has lack of growth hormone short stature with normal proportions mutant allele is dominant Mineral Deposition Mineralization is crystallization process in which ions (calcium, phosphate & others) are removed from blood plasma & deposited in bone tissue Steps of the mineralization process osteoblasts produce collagen fibers that spiral along the length of the osteon in alternating directions fibers become encrusted with minerals hardening matrix ion concentration must reach the solubility product for crystal formation to occur & then positive feedback forms more Ectopic ossification is abnormal calcification may occur in lungs, brain, eyes, muscles, tendons or arteries (arteriosclerosis) Process of dissolving bone & releasing Mineral Resorption minerals into the blood performed by osteoclasts "ruffled border" Braces on the teeth reposition teeth by hydrogen pumps in the cell membrane secrete hydrogen ions into the space between the osteoclast & the bone chloride ions follow by electrical attraction hydrochloric acid & a pH of 4 dissolve bone minerals an enzyme (acid phosphatase) digests the collagen creating greater pressure of the tooth on the bone stimulating osteoclasts & osteoblasts to remodel jaw Normal stress on bone Stress fracture is a break caused by Fractures and Their Repair abnormal trauma to a bone Pathological fracture is a break in a bone car accident, fall, athletics, etc weakened by some other disease bone cancer or osteoporosis Fractures are classified by their structural characteristics causing a break in the skin, breaking into multiple pieces, etc or after a physician who first described it Types of Bone Fractures Normally healing takes 8 12 weeks (longer in Healing of Fractures elderly) Stages of healing fracture...
View Full Document

This note was uploaded on 03/10/2012 for the course BIOL 2403 taught by Professor Campbell during the Spring '12 term at Texas Pan American.

Ask a homework question - tutors are online