8Classification of Bones: Long bones:Arm and leg bonesShort bones:Wrist bonesFlat bones:The bones of the skullIrregular bones:Facial bones or vertebrae
9Structure of Bones: Bones are living! (osteocytes) Bones are solid networks of living cells and protein fibers that are surrounded by deposits of calcium salts.Bones contain nerves, blood vessels & marrow
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 Structure (cont.)Ends of Bones are lined with dense tissue: cartilageCushions bonesProvides support
19Tendons: Tough fibers that connect muscle to bone Bone Structure (cont.)Tendons: Tough fibers that connect muscle to bone
20Ligaments: Tough fibers that connect bone to bone Bone Structure (cont.)Ligaments: Tough fibers that connect bone to bone
21Bone 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.
22OsteoporosisOsteoclast activity is faster than osteoblast activity!
24Development 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).
25Development 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
26Growth:Long bones contain growth plates called epiphyseal lines at either ends
27Growth: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