Lecture exam 3 - bio

greenstick fracture

bending and incomplete break of a bone; most often seen in children

long bone

longer than they are wide

bone remodeling

ongoing replacement of old bone tissue by new bone tissue

process of bone resorption

1. Osteoclasts attach to the bones surface via integrins (membranes and attached proteins) and form a sealing zone that isolates the area immediately below the osteoclast 2. Proton pumps (H+ dependent ATPases) move into osteoclast membrane (sealing zone) next to the bone 3. Proton pumps acidify the underlying area to pH 4 4. This dissolves the hydroxyapatite into soluble calcium and phosphate 5. Osteoclasts also secret acid proteases which dissolve collagen

periosteum

A dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles.

central canal

A tiny channel found within the spinal cord and inferior medulla oblongata

intersititial lamellae

Areas between neighboring osteons

osteoclasts

Bone-destroying cells

epiphyseal plate

Growth plate, made of cartilage, gradually ossifies

bone tissue

Most rigid connective tissue, Internally supports body structures, very active tissue, heals much more rapidly than cartilage

endochondral ossification

Process of transforming cartilage into bone.

protection

Skin covers the body and acts as a physical barrier that protects underlying tissue from physical cut, bacterial invasions, dehydration and sunburn.

flat bones

These bones are thin, flat, and curved. They form the ribs, breastbone, and skull.

epiphyseal plate fracture

a break in the bone at the growth plate (typically at the wrist or ankle)

spiral fracture

a fracture in which the bone has been twisted apart

hydroxyapatite crystals

accounts for 2/3 of the weight of bone; formed when calcium phosphate interacts with calcium hydroxide - inorganic matrix

intramembranous ossification

bone develops from a fibrous membrane

osteogenisis

bone formation

mineral storage and acid-base homeostasis

bone is most important storehouse in body for calcium, phosphorus, and magnesium salts; these minerals, also present in blood as electrolytes, acids, and bases; critical for electrolyte and acid-base maintenance

osteoblast

bone-forming cell

irregular bones

bones of the vertebrae and face

fat storage

bones store yellow bone marrow

perforating canal

canal perpendicular to the central canal, carries blood vessels and nerves

support

carrying the weight of the body

medullary cavity

cavity within the shaft of the long bones filled with bone marrow

articular cartilage

covers the surfaces of bones where they come together to form joints

osseous tissue

connective tissue in which the matrix is hardened by the deposition of calcium phosphate and other minerals

inorganic matrix

consisting of minerals makes up about 65% of bones total weight

short bones

cube shaped bones of the wrist and ankle

epiphyses

ends of long bone

yellow bone marrow

fatty tissue found in the medullary cavity of most adult long bones

circumfrential lamellae

found at the outer and inner surfaces of the bone, where they are covered by the periosteum and endosteum.

red bone marrow

found in cancellous bone; site of hematopoiesis

epiphyseal lines

found separating both proximal and distal epiphyses from diaphysis

comminuted fracture

fracture in which the bone is splintered or crushed

avulsion fracture

fragment of bone chipped away from the main bone

longitudinal growth

growth in length

appositional growth

growth in width

blood-cell formation

hematopoiesis occurs within the marrow cavities of bones

organic matrix

makes up remaining 35%; consists of collagen fibers and usual ECM components

osteocytes

mature bone cells

endosteum

membranous lining of the hollow cavity of the bone

movement

muscles produce movement via attachment to bones

compression fracture

occurs when the bone is pressed together (compressed) on itself

ossification

process of bone formation

cannliculi

radiating from the lacunae which contain extracellular fluids, allow communication between neighboring lacunae (gap junctions) provides routes for nutrients, oxygen, waste to and from HC

primary ossification center

region, deep in the periosteal collar, where bone development starts during endochondral ossification

lamellae

rings around the central canal, sites of lacunae

sesamoid bones

round bones found near joints

perforating fibers

secure periosteum to underlying bone

diaphyses

shaft of a long bone

lacunae

small cavities in bone that contain osteocytes

nutrient foramen

small opening in the middle of the external surface of the diaphysis, through which an artery enters the bone to provide nourishment

diploe

spongy bone in flat bones

osteogenic cells

stem cells that differentiate into osteoblasts

osteon

structural unit of compact bone

functions of skeletal system

support, protection, movement, storage, blood cell production

trabeculae

supporting bundles of bony fibers in cancellous (spongy) bone

bone deposition

the addition of minerals and collagen fibers to bone by osteoblasts

bone resorption

the removal of minerals and collagen fibers from bone by osteoclasts

secondary ossification centers

this develops in the epiphyses of bone during endochondral ossification; in longer bones is occurs at both ends, in shorter bones it occurs in only one epiphysis

osteoid

unmineralized bone matrix composed of proteoglycans, glycoproteins, and collagen