BIOL 141 Lecture Notes - Lecture 6: Hyaline Cartilage, Bone, Bone Remodeling
Document Summary
Compact bone: lightly packed, no gaps in extracellular matrix. Medullary cavity: hollow channel, continuous with spongy bone. Osteon: osteocytes (bone cells) and extracellular matrix clustered around central canal. Intramembranous bones: originate with sheet-like layers of connective tissue. Endochondral bones: originate as hyaline cartilage later replaced by bone (majority) Epiphyseal plate: growth plate, band of cartilage that separates the diaphysis and epiphysis. Osteoclasts: large, multinucleated cells absorb bone material and hollow out the bone (eat the bone to make room for the things we need. Bone remodeling: throughout life osteoclasts reabsorb and osteoblasts replace. Nutrition- vitamin d (sunlight) and calcium absorption; vitamins a and c. Sex hormones- estrogen and testosterone promote bone growth. Calcium- muscle cell contraction, nerve impulse conduction, blood clot formation. Osteoporosis: weakened bone due to decrease in bone mass. Women have less bone mass and hormonal changes (take calcium to prevent, women more prone to osteoporosis because of decrease in estrogen)
