a&p mod 6 - bones & bone structure

axial skeleton

bones of skull, thorax and vertebral column (80)

appendicular skeleton

bones of the limbs and girdles that attach to the axial skeleton (126)

associated cartilages

ligaments and other connective tissues

flat bones

thin, roughly parallel surfaces that protect underlying soft tissues and provide surface area for skeletal muscle attachment

cranial bones, sternum, ribs, scapulae

examples of flat bones

sutural bones

irregular bones formed between cranial bones: number, shape and size vary

long bones

relatively long and slender

various bones of the limbs

examples of long bones

sesamoid bones

small, flat and somewhat shaped like a sesame seed; develop inside tendons; individual variation in location and number

patella

example of sesamoid bone

short bones

small and boxy bones

bones of the wrist (carpals) and ankles (tarsal)

examples of short bones

irregular bones

complex shapes with short, flat, notched or ridged structures

vertebrae, bones of pelvis, facial bones

examples of irregular bones

bone markings (surface features)

elevations, projections, depressions, grooves or tunnels that relate to particular functions of the bones

epiphysis

at proximal and distal ends of long bone

diaphysis

shaft of a long bone

medullar cavity

cavity with bone marrow

Periosteum

protective outer layer of bone

spongy bone

found in epiphysis; consists of trabeculae

compact bone

found in diaphysis

endosteum

thin layer that rebuilds bone tissue

nutrient artery/vein

commonly one of each per bone; nutrient foramen

nutrient foramen

tunnel providing access to marrow cavity

metaphyseal artery/vein

carry blood to/from metaphysis and connects to epiphyseal arteries/veins

ossification

production of osseous tissue

appositional growth

growth in width; occurs when new circumferential lamellae are created

layers of periosteum

fibrous outer layer and cellular inner layer

perforating fibers

protein fibers tying periosteum to osseous tissue

endochondral ossification

process of turning cartilage into bone

interstitial growth

growth in length

epiphyseal closure

during puberty hormones stimulate increased bone growth and epiphyseal cartilage is repaired and narrows until it disappears; leaves epiphyseal line in adults

fracture

crack/break due to extreme mechanical stress

closed/simple fracture

no break in skin; only seen on x-rays

open/compound fracture

broken bone projects though the skin; more dangerous due to infection and uncontrolled bleeding

transverse fractures

break shaft perpendicular across long axis

spiral fractures

produced by twisting stresses, spreads along length of bones, typically oblique

compression fractures

occur in vertebrae subjected to extreme stresses, often associated with osteoporosis

greenstick fractures

one side of shaft is broken, one side is bent; typically occurs in children since long bones have yet to fully ossify

displaced fractures

produce new and abnormal bone arrangements

nondisplaced fractures

retain normal alignment

comminuted fractures

shatter affected area producing fragments

epiphyseal fractures

occurs where bone matrix is calcifying; breaks between epiphyseal plate and cartilage can stop growth at site

fracture repair

fracture hematoma formation, callus formation, spongy bone formation, compact bone formation

internal callus

network of spongy bone that unites inner edges of fracture

external callus

composed of cartilage and bone and stabilized outer edges of fracture

spongy bone formation

cartilage of external callus replaced by spongy bone; bone fragments and dead bone are moved and replaced; ends of fracture held firmly in place

compact bone formation

spongy bone replaced by compact bone; remodeling over time eliminated evidence of fracture

shortened bones

disorder resulting in shorten growth caused by pituitary failure and inadequate growth hormone

gigantism

disorder causing lengthened bone caused by pituitary tumors and overproduction of growth hormones before puberty

acromegaly

disorder growth in adulthood caused by overactivity of growth hormones after epiphyseal plates close; bones get thicker not longer and alterations in soft tissue structure changes physical features, especially in face jaw and hands

achondroplasia

disorder limiting cartilage growth (dwarfism) caused by slow growth of epiphyseal cartilage of long bones

marfan syndrome

inherited metabolic condition caused by excessive cartilage formation at epiphyseal cartilage; results in a very tall person with long slender limbs and affects other connective tissues throughout the body

Fibrodysplasia Ossificans Progressiva (FOP)

caused by genetic mutations and results in bone disposition around skeletal muscles and bones develop in unusual places

heterotopic/ectopic bones

Bones that develop in unusual places

ricketts

softening/weakening of bones due to low vitamin D, calcium, or hormone levels

osteopenia

inadequate ossification leading to loss of bone mass

osteoporosis

bone loss sufficient to affect normal function

central test

measures hip and/or vertebrae

peripheral test

measures arm, leg, finger, heel, etc

t score

a measurement of how dense the bone is compared to a healthy 30 year old

bone density treatment

diet, medications, movement/stress, limiting risk of fracture

osteogenic cells

stem cells producing cells that differentiate into bone producing cells (osteoblasts)

location of osteogenic cells

inner lining of periosteum, lining endosteum in medullary cavity, lining passageways containing blood vessels

osteoblasts

produces new bony matrix (ossification)

osteocytes

mature osteoblasts that are surrounded by matrix; occupy lacunae and maintains calcified osteoid in compact or spongy bone

osteoclasts

remove and remodel bone matrix; contributes to increasing calcium levels in the blood

osteolysis

release acids and proteolytic enzymes to dissolve matrix

collagen fibers

account for 1/3 of bone weight and provides flexibility

calcium salts

accounts for 2/3 of bone weight and provides rigidity

central canal

contains blood vessels and nerves

circumferential lamellae

layers of calcified osteoid deposited on the superficial and deep surfaces of compact bone; surrounds diaphysis

interstitial lamellae

fill spaces between osteons

primary ossification center

helps create diaphysis of long bone; located in diaphysis

osteon

circular unit of compact bone containing multiple lamellae, lacunae, osteocytes, and a central canal

elevations

bone marking allows for muscle tendon and ligament attachment

lamellae

concentric layers of bone tissue

red bone marrow

found in between trabeculae

osteoclastic crypts

shallow depressions where osteoclasts are found

initial embryonic skeleton is made of

hyaline cartilage