Transcript of "2401 lecture05 ch 6 bones and bone tissue for class and web"
BIOLOGY 2401ANATOMY & PHYSIOLOGY PART I CHAPTER 6 Bones and Skeletal Tissues 1
Skeletal Cartilages• The skeletal cartilages are surrounded by a dense irregular connective tissue called the perichondrium. – Supplies nutrients & removes wastes from cartilage through diffusion from a rich vasculature• Three types – Hyaline cartilage – Elastic cartilage – Fibrocartilage• Chondrocytes located within lacunae. 2
Functions of Bones• Support• Protection• Movement• Mineral storage• Blood cell formation 6
Long Bone Structure• Diaphysis – shaft – Compact bone surrounded by periosteum & endosteum • osteoblasts and osteoclasts – Central medullary cavity • in adults: filled with yellow bone marrow – fat storage• Epiphyses – ends – proximal and distal – Spongy bone – Hyaline cartilage at articulations 7
Structure of Other Bone ShapesShort, irregular, and flat bones – Periosteum and endosteum – Dense bone on outer part – Spongy bone in middle part 9
Hematopoietic Tissues• Red bone marrow – In adults red bone marrow is found in the spongy bone of the femur, humerus, sternum, and pelvic girdle (hip bone) – In infants, red bone marrow is found in all the bones. 10
Microscopic Structure of Bone: Compact (Dense) BoneThe osteons are the structural units of dense bone (formerly known as Haversian systems). – Columns that run parallel to long axis of the bone. – Each is ringed like a tree. • A lamella is an individual ring. • A lacuna is a space found between the lamellae. • Osteocytes are the cells that occupy the lacunae.The osteon is traversed by canals for blood vessels and nerves. Central (Haversian) canal runs down the center of the osteon Perforating (Volkman) canal runs perpendicular to the osteon Canaliculi connect the lacunae. 11
Chemical Composition of Bone• 35% of bone is organic – Osteocytes, osteoblasts, osteoclasts. – Ground substance and collagen fibers.• 65% of bone is inorganic – Calcium phosphate • Also known as Hydroxyapatites • The minerals form small crystals around the collagen fibers 13
Types of FracturesComminuted fracture – bone breaks into 3 or more piecesCompression fracture – bone is crushedSpiral fracture – ragged break in bone due to twistingEpiphyseal fracture – epiphysis separates from diaphysisDepressed fracture – skull fractures inwardGreenstick fracture – only one side of bone breaks; the other side bends. Common in children. 14
Repair of Fractures: 4 steps– Hematoma formation – mass of clotted blood– Callus formation – “soft callus” (cartilaginous) splint– Bony callus formation – “hard callus” (spongy bone)– Bone remodeling – remove spongy bone of hard callus, replace with compact bone 15
Homeostatic Imbalances of Bone• Osteomalacia – Inadequate bone mineralization – Pain with stress on bones – Known as Rickets in children – Due to insufficient calcium leading to inadequate mineralization in youth. – Bowed bones and improper formation. – Vitamin D deficiency• Osteoporosis – Over activity of osteoclasts. 16
A condition that produces a reduction in bone mass sufficient to compromise normal function isB. osteopenia.C. osteoporosis.D. osteitis.E. osteomyelitis.F. osteomalacia.
A major difference between bone tissue and other connective tissues lies in which of the following?C. The limited blood supply available to bone tissueD. The inability of bone cells to metabolize nutrients for energyE. The presence of collagen fibers in boneF. The presence of elastic fibers in boneG. The composition of the intercellular substance of bone
How would increasing the proportion of organic molecules to inorganic components in the bony matrix affect the physical characteristics of bone?B. The bones would be stronger.C. The bones would be more brittle.D. The bones would be more flexible.E. The bone would be less flexible.F. The bones would be less compressible.
Long bones differ from flat bones in that long bonesB. have an outer layer of compact bone.C. have epiphyses.D. contain marrow.E. have a periosteum membrane.F. contain spongy bone.
The bones of the skeleton store energy reserves as lipids in areas ofB. yellow marrow.C. red marrow.D. the ground substance.E. spongy bone.F. the matrix of bone tissue.
The cells that maintain mature compact bone areB. osteocytes.C. lacunae.D. osteoclasts.E. chondrocytes.F. osteoblasts.
The lacunae of bone containB. blood cells.C. osteons.D. chondroblasts.E. bone marrow.F. osteocytes.
A fracture in the shaft of a bone would occur in theB. metaphysis.C. epiphysis.D. diaphysis.E. epiphyseal line.
Osteocytes maintain contact with the blood vessels of the central canal throughB. periosteum.C. canaliculi.D. drainage canals.E. concentric lamellae.
Spongy bone contains all of the following exceptB. true osteons.C. collagen fibers.D. hydroxy apatite.E. trabeculae.
Collagen in the bone matrix provides flexible strength. True False
Mature bone cells are called chondrocytes. True False
The central canal of an osteon contains osteocytes. True False
The most abundant mineral in the human body is calcium. True False
The shaft of the long bone is called the diaphysis. True False
Vitamin D is necessary for the formation of the organic framework of bone. True False