14Structure of Long BonePeriosteum- tough layer of connective tissueCompact bone- found beneath periosteumHaversian canals- network of tubes that run through compact bone & contain blood vessels and nerves.
15Structure of Long Bone: Spongy bone- ends of long bones & middle of short, flat bones.Adds strength w/o mass!Within bones are cavities that contain a soft tissue called bone marrow.
16Structure of Long Bone: Two types of bone marrow:Yellow bone marrow- made up of fat cellsRed bone marrow- produces red blood cells, white blood cells, & platelets
18Bone Cells:Osteocytes- mature bone cells that are embedded in the matrixOsteoclasts- break down boneOsteoblasts- produce boneStop growing- late teens!Our Bones are continuously remodel throughout our lives.
19OsteoporosisOsteoclast activity is faster than osteoblast activity!
21Development of Bones:Skeleton of embryo almost entirely cartilage:Cartilage is a type of connective tissue that is made up of a network of protein fibers (both tough collagen & flexible elastin).
22Development of Bone Cont’d: Cartilage does not contain blood vessels!Cartilage is replaced by bone during the process called ossification:Osteoblasts secrete mineral deposits that replace cartilage with bone.Osteoblasts surrounded by bone tissue – now osteocytes
23Growth:Long bones contain growth plates called epiphyseal lines at either ends
24Growth:Growth of cartilage at these plates causes the bones to lengthen.Gradually cartilage replaced by bone- a.k.a. ossificationLate adolescence/ early adulthood growth plates replaced by bone- stop growing!Cartilage in adults found:- nose, external ears, attach ribs to sternum