Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 1 Chapter 7 Skeletal Tissues

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 2 Types of Bones  Structurally, there are four types of bones  Long bones  Short bones  Flat bones  Irregular bones  Bones serve various needs, and their size, shape, and appearance will vary to meet those needs

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 3 Types of Bones  Bones vary in their proportions of compact and cancellous (spongy) bone; compact bone is dense and solid in appearance, whereas cancellous bone is characterized by open space partially filled with needle-like structures

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 4 Types of Bones  Parts of a long bone  Diaphysis Main shaft of long bone Main shaft of long bone Hollow, cylindrical shape and thick, compact bone Hollow, cylindrical shape and thick, compact bone Function is to provide strong support without cumbersome weight Function is to provide strong support without cumbersome weight

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 5 Types of Bones  Parts of a long bone  Epiphyses Both ends of a long bone, made of cancellous bone filled with marrow Both ends of a long bone, made of cancellous bone filled with marrow Bulbous shape Bulbous shape Function is to provide attachments for muscles and give stability to joints Function is to provide attachments for muscles and give stability to joints

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 6

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 7 Types of Bones  Parts of a long bone  Articular cartilage Layer of hyaline cartilage that covers the articular surface of epiphyses Layer of hyaline cartilage that covers the articular surface of epiphyses Function is to cushion jolts and blows Function is to cushion jolts and blows

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 8 Types of Bones  Parts of a long bone  Periosteum Dense, white, fibrous membrane that covers bone Dense, white, fibrous membrane that covers bone Attaches tendons firmly to bones Attaches tendons firmly to bones Contains cells that form and destroy bone Contains cells that form and destroy bone Contains blood vessels important in growth and repair Contains blood vessels important in growth and repair Contains blood vessels that send branches into bone Contains blood vessels that send branches into bone Essential for bone cell survival and bone formation Essential for bone cell survival and bone formation

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 9 Types of Bones  Parts of a long bone  Medullary (or marrow) cavity Tubelike, hollow space in diaphysis Tubelike, hollow space in diaphysis Filled with yellow marrow in adult Filled with yellow marrow in adult  Endosteum—thin epithelial membrane that lines medullary cavity

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 10

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 11 Types of Bones  Short, flat, and irregular bones  Inner portion is cancellous bone, covered on the outside with compact bone  Spaces inside cancellous bone of a few irregular and flat bones are filled with red marrow

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 12 Bone Tissue  Most distinctive form of connective tissue  Extracellular components are hard and calcified  Rigidity of bone allows it to serve its supportive and protective functions  Tensile strength is nearly equal to cast iron at less than one third the weight

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 13 Microscopic Structure of the Bone  Compact bone  Contains many cylinder-shaped structural units called osteons, or Haversian systems  Osteons surround canals that run lengthwise through bone and are connected by transverse Volkmann’s canals  Living bone cells are located in these units, which constitute the structural framework of compact bone  Osteons permit delivery of nutrients and removal of waste products

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 14

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 15 Microscopic Structure of the Bone  Compact bone  Four types of structures make up each osteon: Lamella—concentric, cylinder-shaped layers of calcified matrix Lamella—concentric, cylinder-shaped layers of calcified matrix Lacunae—small spaces containing tissue fluid in which bone cells are located between hard layers of the lamella Lacunae—small spaces containing tissue fluid in which bone cells are located between hard layers of the lamella Canaliculi—ultrasmall canals radiating in all directions from the lacunae and connecting them to each other and to the Haversian canal Canaliculi—ultrasmall canals radiating in all directions from the lacunae and connecting them to each other and to the Haversian canal Haversian canal—extends lengthwise through the center of each osteon and contains blood vessels and lymphatic vessels Haversian canal—extends lengthwise through the center of each osteon and contains blood vessels and lymphatic vessels

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 16

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 17 Microscopic Structure of the Bone  Cancellous bones  No osteons in cancellous bone; instead, it has trabeculae  Nutrients are delivered and waste products removed by diffusion through tiny canaliculi  Bony spicules are arranged along lines of stress, enhancing the bone’s strength

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 18 Microscopic Structure of the Bone  Blood supply  Bone cells are metabolically active and need a blood supply, which comes from the bone marrow in the internal medullary cavity of cancellous bone  Compact bone, in addition to bone marrow and blood vessels from the periosteum, penetrate bone and then, by way of Volkmann’s canals, connect with vessels in the Haversian canals

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 19 Microscopic Structure of the Bone  Types of bone cells  Osteoblasts Bone-forming cells found in all bone surfaces Bone-forming cells found in all bone surfaces Small cells synthesize and secrete osteoid, an important part of the ground substance Small cells synthesize and secrete osteoid, an important part of the ground substance Collagen fibrils line up in osteoid and serve as a framework for the deposition of calcium and phosphate Collagen fibrils line up in osteoid and serve as a framework for the deposition of calcium and phosphate

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 20 Microscopic Structure of the Bone  Types of bone cells  Osteoclasts Giant multinucleate cells Giant multinucleate cells Responsible for the active erosion of bone minerals Responsible for the active erosion of bone minerals Contain large numbers of mitochondria and lysosomes Contain large numbers of mitochondria and lysosomes  Osteocytes—mature, nondividing osteoblast surrounded by matrix, lying within lacunae