1Skeletal SystemChapter 7.1Chapter 7.1ObjectiveObjective--Read 7.1 and understand that bones Read 7.1 and understand that bones are alive and multifunctional.are alive and multifunctional.Introduction:Introduction:A.A.Bones are very active tissuesBones are very active tissuesB.B.Each bone is made up of several types of Each bone is made up of several types of tissues and so is an organ.tissues and so is an organ.C. C. Bone functions include: muscle Bone functions include: muscle attachment, protection and support, attachment, protection and support, blood cell production blood cell production and storage of and storage of mineralsmineralsCopyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.2Section 7.2Section 7.2ObjectiveObjective--Read 7.2 and appreciate the various Read 7.2 and appreciate the various size and shape of bone and be able to describe size and shape of bone and be able to describe in detailin detailthe parts of long bone and microscopic the parts of long bone and microscopic structures.structures. Bone StructureA. Bones differ in size and shape, yet are similar in several ways.Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.3B.B.Parts of a Long Bone Parts of a Long Bone 1.1.Expanded ends of bones that Expanded ends of bones that form joints with adjacent bones form joints with adjacent bones are called are called epiphyses.epiphyses.2.2.ArticularArticularcartilagescartilages(hyaline (hyaline cartilage) cartilage) cover the epiphyses.cover the epiphyses.Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.3.3.The shaft of the bone is the The shaft of the bone is the diaphysisdiaphysis..4.4.A tough layer of vascular connective tissue, A tough layer of vascular connective tissue, called the called the periosteumperiosteum, covers the bone and , covers the bone and is continuous with ligaments and tendons. is continuous with ligaments and tendons. 5.5.A bone's shape makes possible its A bone's shape makes possible its function; bony function; bony processes or grooves processes or grooves indicate places of attachment for indicate places of attachment for muscles.muscles.Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.6.6.CompactCompactbone makes up the wall of the bone makes up the wall of the diaphysisdiaphysis; the epiphyses are filled with ; the epiphyses are filled with spongy spongy bone to reduce the weight of bone to reduce the weight of the skeleton.the skeleton.7.7.The The diaphysisdiaphysiscontains a hollow contains a hollow medullarymedullarycavitycavitythat is lined with that is lined with endosteumendosteumand and filled filled with with marrowmarrow. . Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.4Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Do nowDo now--List five List five major parts of long major parts of long bone.bone.1.1.Bone cells (Bone cells (osteocytesosteocytes) are located within ) are located within lacunaelacunaethat lie in concentric circles that lie in concentric circles around around osteonicosteoniccanalscanals..2.2.OsteocytesOsteocytespass nutrients and gasses in the pass nutrients and gasses in the matrix through matrix through canaliculicanaliculi. . 3.3.Intercellular material consists of Intercellular material consists of collagen and inorganic salts. collagen and inorganic salts. C.C.Microscopic StructureMicroscopic Structure54.4.In compact bone, In compact bone, osteocytesosteocytesand intercellular and intercellular material are organized into material are organized into osteonsosteonsthat are that are cemented together.cemented together.5.5.OsteonicOsteoniccanals contain blood vessels and canals contain blood vessels and nerve nerve fibers, and extend longitudinally fibers, and extend longitudinally through bone.through bone.Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.6.6.OsteonicOsteoniccanals are interconnected by canals are interconnected by transverse transverse perforating canalsperforating canals..7.7.Unlike compact bone, the Unlike compact bone, the osteocytesosteocytesand and intercellular material in spongy bone are not intercellular material in spongy bone are not arranged around arranged around osteonicosteoniccanals.canals.Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Do nowDo now--What is structures are found in What is structures are found in the central canal of the central canal of osteonsosteonsand how and how do do osteocytesosteocytesget there nutrients?get there nutrients?6Section 7.3Section 7.3ObjectiveObjective--Read 7.3 and distinguish between Read 7.3 and distinguish between intramembranousintramembranousand and endochondralendochondraldescribe describe the bone development of long (the bone development of long (endochondralendochondral) ) bone. bone. Bone Development and GrowthA.Bones form by replacing connective tissue in the fetus.B. Some form within sheetlike layers of connective tissue (intramembranous bones), while others replace masses of cartilage (endochondral bones). Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.7C.Intramembranous Bones1. The flat bones of the skull form as intramembranous bones that develop from layers of connective tissue.2. Osteoblasts deposit bony tissue around themselves.Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.3. Once osteoblasts deposit bone are located in lacunae, they are called osteocytes.4. Cells of the membranous connective tissue that lie outside the developing bone give rise to the periosteum. Copyright©The McGraw-Hill Companies, Inc. Permission required for reproduction or display.1. Most of the bones of the skeleton fall into this category.2. They first develop as hyaline cartilage models and are then replaced with bone. C.Endochondral Bones3. Cartilage is broken down in the diaphysisand progressively replaced with bone while the periosteum develops on the outside.4. Cartilage tissue is invaded by blood vessels and osteoblasts that first form spongy bone at the primary ossification center in the
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