BIO E121 Lecture 16: Bio_E_121_-_Class_16_(Spring)
Document Summary
On average, there are 206 bones in adults. Bone is a living tissue, but most noticeable characteristics result from nonliving components: the solid matrix. Hard due to calcium and phosphorus salts. Resilient due to strands of elastic protein collagen. Embryo (babies) start with no bones, only cartilage. Cartilage cell can undergo cell division; thus, keeps up with rapid growing fetus. At 10 weeks embryos are all cartilaginous material and ossifies into bone. All fetal bones have rbm (red bone marrow) Provides a place of attachment for muscles; therefore, providing body movement. Certain bones produce blood cells in red marrow. Varying proportions of compact & spongy bone. Found in concentric rings (lamella) within small space called lacuna. Arm like extensions travel through tiny canals called canaliculi. Nutrients & waste travel through the blood vessels in the central canal and perforating (volkmann"s) canals. Lamella 1 layers, concentric rings. Canaliculi allows communication from lacuna to another. Perforating canals connects to other osteons.
