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Ch. 6 Osseus+Bone
Osseous Tissue and Bone Structure
Question | Answer |
---|---|
Long Bones | Relatively long and slender bones; located in the arm, forearm, thigh and leg, palms, soles, fingers, and toes. |
Flat Bones | Bones that have thin roughly parallel surfaces; form the roof of the skull, the sternum, the ribs, and scapulae; extensive surface area for the attachment of skeletal muscles |
Sutural Bones | Small flat irregularly shaped bones found between the flat bones of the skull. |
Irregular Bones | Bones that have complex shapes; the spinal vertebrae, bones of the pelvis, and several skull bones |
Short Bones | Small and boxy bones; carpal bones (wrists) and tarsal bones (ankles) |
Sesamoid Bones | Bones that are generally small, flat, and shaped somewhat like a sesame seed; the develop inside tendons and are most commonly located near joints at the knees, the hands, and the feet |
Bone Markings/Surface Features | Depressions, grooves, and tunnels in the bone that indicate sites where blood vessels or nerves lie alongside or penetrate the bone |
Process | Any projection or bump |
Ramus | An extension of a bone making an angle eith the rest of the structure |
Trochanter | A large, rough projection |
Tuberosity | A smaller, rough projection |
Tubercle | A small, rounded projection |
Crest | A prominent ridge |
Line | A less prominent ridge |
Spine | A pointed or narrow process |
Head | The expanded articular end of an epiphysis, separated from the shaft by a neck |
Condyle | A smooth, rounded articular process |
Trochlea | A smooth, grooved articular process shaped like a pully |
Facet | A small, flat articular surface |
Fossa | A shallow depression |
Sulcus | A narrow groove |
Foramen | A rounded passageway for blood vessels or nerves |
Canal or Meatus | A passageway through the substance of a bone |
Fissure | An elongated cleft |
Sinus or Antrum | A chamber within a bone, normaly filled with air |
Diaphysis | The shaft of a long bone. Heavy wall of compact/dense bone. Central space called the medullary cavity/marrow |
Epiphysis | The wider head/ends of a long bone. Articulation with other bones. Mostly spongy/cancellous bone. Covered with cortex (compact bone) |
Metaphysis | The narrow region of a long bone between the epiphysis and diaphysis, corresponding to the location of the epiphyseal cartliage of the developing bone |
Cortex | The outer layer of a bone. Plates that resemble latticework with a thin covering |
Hydroxyapatite | Crystals formed by the reactions of calcium phosphate with calcium hydroxide. Ca10(PO4)6(OH)2. Incorporates other calcium salts and ions. |
Osteocytes | Mature bone cells that account for most of the cell population; major functions are maintaining the protein and mineral content of the surrounding matrix and participate in the repair of damaged bone. |
Lacuna | A pocket sandwiched between layers of matrix. House osteocytes. |
Lamellae | Thin layers of bone. Concentric=round layers around blood vessel central canals, Interstitial=between osteons, circumferential=around long bone circumfrence deep to periosteum, binding osteons together. |
Canaliculi | Form pathways for blood vessels through matrix between lacunae and proximal blood vessels. Exchange nutrients and wastes. |
Osteoblasts | Produce new bone matrix; immature bone cells that secret organic components of the matrix. Change tissue to allow Ca deposition in bone for strength |
Osteogenesis | The process of producing new bone matrix. "Bone creation" |
Osteoid | The proteins and organic matrix before calcium salts are deposited |
Osteoprogenitor Cells | Less specialized mesenchymal stem cells whose divisions produce osteoblasts. Important in fracture repair. In inner cellular layer of periosteum, endosteum (around medulalry cavities), and in lining of blood vessel canals. |
Osteoclasts | Giant cells that remove and recycle bone matrix; multinucleated cells that secrete acids and proteolytic enzymes to dissolve bone matrix and release stored minerals. Derived from same stem cells that produce monocytes and macrophages. |
Osteolysis | AKA resorption. The bone erosion process, important for the regulation of calcium and phosphate concentration in body fluids |
Osteon/Haversian System | Basic functional unit of mature compact bone. Concentric osteocyte layers around a central/Haversian canal. Interlaced with perforating fibers of collagen |
Central Canal/Haversian | Longitudinal canal in the center of an osteon typically containing a capillary and tiny vein (venule). |
Perforating Canal/Volkmanns Canals | Perpendicular to central canal, carrying blood vessels into bone and marrow. |
Spongy Bone Structure | Osteon-lacking matrix forming an open, spacey network of vessel-lacking trabeculae. Space between trabeculae filled with vascular red bone marrow. |
Red Bone Marrow | Vascular, forms red blood cells, supplies nutrients to osteocytes. |
Yellow Bone Marrow | Stores fat, is an energy reservoir. Within spongy bone of some bones. |
Periosteum | Covers the outer surfaces of all bones not enclosed in joint capsules. Consists of outer fibrous layer and inner cellular layer (contain osteoprogenitor cells). |
Endosteum | An incomplete cellular lining on the inner (medullary/marrow cavity) surfaces of bones, covers trabeculae of spongy bone, and lines central canals. Contains osteoblasts, osteoprogenitor cells and osteoclasts. Active in bone growth&repair. |
Ossification | The process of replacing other tissues with bone (recycling) |
Calcification | The process of depositing Ca salts. Occurs during ossification and in other tissues. |
Endochondral Ossification | The conversion of hyaline cartilage (most bones) into bone. 6 main steps. Gradually occurring through development. |
Primary Ossification Center | The site where bone development begins |
Secondary Ossification Center | Where epiphysis (ends) begin to calcify, capillaries and osteoblasts migrate to these areas |
Articular Cartilage | The thin cartilage cap that covers the surface of a bone inside a joint cavity, left on surface of epiphyses after ossification. |
Epiphyseal Cartilage/Epiphyseal Plate | A relatively narrow cartilaginous region in the bone that separates the ephysis from the diaphysis at the metaphysis. |
Epiphyseal Line + Epiphyseal Closure | A distinct line, detectable on x-rays, of the former location of epiphyseal cartliage after epiphyseal growth has ended at puberty when bone production by osteoblasts is faster than and overtakes production of cartilage by chondrocytes(epiphyseal closure) |
Intramembranous/Dermal Ossification | Occurs in the deeper layers of the dermis, begins when osteoblasts differentiate within a mesenchymal or fibrous connective tissue. Produces dermal bones such as the flat bones of the skull, mandible, and clavicle. |
Spicules | Outward growths of developing bone in small struts from the ossification center |
Remodeling | The process of the organic and mineral components of the bone matrix continuously being recycled and renewed. Older mineral deposits removed from bone & circulated to be absorbed or deposited elsewhere. May or change the bone structure or mineral reserves |
Calcitriol | Promotes calcium and phosphate ion absorption along the digestive tract; made in kidneys from vitamin D3 (related to sun absorption from prev. chapter) |
Growth Hormone | Stimulates osteoblast activity and the synthesis of bone matrix (protein synthesis and cell growth throughout body); made by pituitary gland |
Thyroxine | With growth hormone, stimulates osteoblast activity and the synthesis of bone matrix (stimulates cell metabolism); made by thyroid gland (follicle cells) |
Sex Hormones | Stimulates osteoblast activity (rate of osteocyte production to replace cartilage after puberty) and the synthesis of bone matrix; Produced by ovaries (estrogen, faster)and testes (androgen) |
Parathyroid Hormone | Stimulates osteoclast (and osteoblast) activity, ELEVATES calcium ion concentrations in body fluids when Ca ion concentration is too low; parathyroid gland |
Calcitonin | Inhibits osteoclast activity; promotes calcium loss at kidneys, REDUCES calcium ion concentrations in body fluids; From special cells called C cells (parafollicular) in the thyroid gland |
Fracture Hematoma | A large blood clot that closes off the injured vessels around a fracture and leaves a fibrous mesh work in the damaged area of bone, the first step in fracture repair |
Fracture | A crack or break in a bone. Heals as long as blood supply and cellular components of the endosteum and periosteum survive. |
External Callus | Enlarged collar of cartilage and bone. A toughened layer of connective tissue that encircles and stabilizes a bone at a fracture site |
Internal Callus | A bridgework of bone trabeculae that unites bone within the marrow cavity and between the broken shaft ends. |
Osteopenia | Inadequate ossification, leading to thinner, weaker bones. Normal part of the aging process, begins between ages 30 and 40. Women lose it more quickly because of the stop of estrogen production (stops stimulation of osteoblast activity). |
Osteoporosis | The reduction in bone mass enough to harm normal function. More severe version of osteopenia. |
Osteoclast-activating Factor | A compound, released by cancers of bone marrow, breast, or other tissues, that produce severe osteoporosis (developed as a secondary effect of many cancers). |
Aromegaly | A condition caused by excess secretion of growth hormone after puberty; skeletal abnormalities develop affecting the cartliages and various small bones |
Gigantism | A condition resulting from an overproduction of growth hormone before puberty |
Marfan Syndrome | An inherited condition linked to defective production of fibruillin, a connective tissue glycoprotein. Extreme height and long, slender limbs are the most obvious physical indications; cardiovascular problems are the most dangerous aspects of this condit |
Osteomalacia | A softening of bone due to a decrease in its mineral content (poor mineralization/mineral production) |
Pitutary Growth Failure/Pituitary Dwarfism | A disorder caused by inadequate production of growth hormone prior to puberty |
Rickets | A childhood osteomalacia disorder that reduces the amount of calcium salts in the skeleton; typically characterized by a bow-legged appearance, because the leg bones bend under the body's weight. |
Scurvy | A condition involving weak, brittle bones as a result of a vitamin C deficency |
Bone Matrix | Contains deposits of calcium salts and bone cells (osteocytes) within lacunae organized around blood vessels (concentric organization). |
Matrix Proteins | 1/3 of bone matrix, protein fibers of collagen. Make bone more flexible. |
Perforating Fibers of Periosteum | Collagen fibers which strengthen bone-ligament, tendon, or joint capsule fibers; or periosteum collagen-bone collagen connections |
3 Blood Calcium Increasing Effects of Parathyroid Hormone | 1. Stimulating osteoclast activity and enhancing the recycling of minerals by osteocytes...2. Increasing rate of Ca ion absorption by intestines (calcitriol enhancing)...3. Decrease rate of excretion of Ca ions at kidneys (pee out less Ca). |
2 Blood Calcium Decreasing Effects of Calcitonin | 1. Inhibiting osteoclast activity (leave mineral matrix alone)...2. Increasing rate of excretion of calcium ions at the kidneys (pee out more Ca ions b/c osteoblast activity continues, producing bone matrix) |
Effect of Vitamin C on bone growth and maintenance | Required for collagen synthesis and stimulation of osteoblast differentiation. (deficiency leads to weak, brittle bones...condition called scurvy) |
Effect of Vitamin A on bone growth and maintenance | Stimulates osteoblast activity |
Effect of Vitamin K and B12 on bone growth and maintenance | Help synthesize bone proteins |
Parts of Body controlled and affected by Calcitonin & Parathyroid Hormone | Bones (store calcium, DECR blood calcium concentration), digestive tract (absorb calcium, INCR blood calcium concentration), kidneys (excrete calcium, DECR blood calcium concentration) |