SKELETAL SYSTEM Flashcards
functions of skeletal system
body support
organ protection
body movement
mineral storage
blood cell production
strong bands of fibrous connective tissue, holds bones together
ligaments
provides flexibility buts resists pulling or compression
collagen
calcium phosphate crystal
hydroxyapatite
imperfect bone formation ; rare disorders caused by any one of a number of faulty genes that results in either too little collagen formation or poor quality collagen
brittle bone disease
bone building cells ; extensive endoplasmic reticulum and numerous ribosomes
osteoblasts
the formation of new bone by osteoblasts called
ossification
can occur multiple times during life; fetus and any time when a fracture is repaired
ossification or osteogenesis
osteoblasts become _ once osteoblasts have secreted sufficient bone matrix
osteocytes
osteocyte cell bodies are housed within the bone matrix in spaces called
lacunae
osteocyte cell extensions are housed in narrow, long spaces called
canaliculi
bone destroying cells ; break down bone ; develop in the red bone marrow
osteoclasts
breakdown of bone is called _ ; important for mobilizing calcium and phosphate ions used for metabolic processes
bone reabsorption
osteoclasts develop ; specialized reabsorption specific area of the membrane
ruffled border
mature bone
lamellar bone
lamellar bone is organized into thin, concentric sheets or layers
lamellae
functional unit of compact bone ; composed of concentric rings of matrix, which surround a central tunnel and contain osteocytes
osteon
eye of the osteon ; lined with endosteum and contain blood vessels, nerves, and loose connective tissue
central canal
solid, outer layer surrounding each bone ; has more matrix and is denser with fewer pores
compact or cortical bone
spongy bone consists of interconnecting rods or plates of bone called
trabeculae
appears porous, has less bone matrix and more space
spongy bone
the center portion of a long bone
diaphysis
composed primarily of compact bone tissue surrounding a hollow center called
medullary cavity
end of a long bone are called ; mostly spongy bone with an outer layer of compact bone
epiphyses
end of long bone is covered with hyaline cartilage
articular cartilage
located between epiphysis and diaphysis
epiphyseal plate or growth plate
when bone stops growing in length, the plate become ossified
epiphyseal line
site of blood cell formation
red marrow
mostly adipose tissue
yellow marrow
a connective tissue membrane covering the outer surface of a bone
periosteum
blood vessels and nerves
outer layer
bone cells; osteoblasts and osteoclasts
inner layer
single layer of connective tissue that lines the internal surfaces of all cavities within bones such as the medullary cavity of the diaphysis and smaller cavities in spongy and compact bone
endosteum
two processes of bone formation
intramembranous ossification and endochondral ossification
locations in the membrane where intramembranous ossification begins
centers of ossification
soft spots ; membrane covered spaces between developing skull bones that have not yet been ossified ; close by 2 years old
fontanels
skull bones, part of the mandible, and diaphyses of clavicles (collarbones) develop by
intramembranous ossification
based of the skull, part of mandible, epiphyses of clavicle, and remaining skeletal system develop through
endochondral ossification
this type of bone grow by creating new cartilage in the epiphyseal plate
long bone
bone that becomes old is replaced with new bone in a process called
bone remodeling
living tissue that can repair itself if it is damaged
bone
occurs when an open wound extends to the site of the fracture or protrudes through the skin
open fracture
if skin is not perforated the fracture is called
closed fracture
does not extend completely across the bone
incomplete fracture
bone is broken into two fragments
complete fracture
complete fracture in which the bone breaks into more than two pieces usually two major fragments and a smaller fragment
comminuted fracture
one fragment is driven into the spongy portion of the other fragment
impacted fracture
run parallel to the length of the bone
linear fracture
right angles to the length of the bone
transverse fracture
helical course around the bone
spiral fractures
run obliquely in relation to the length of the bone
oblique fractures
rough, toothed, broken ends
dentate fractures
have breakage lines radiating from a central point
stellate fractures
calcium homeostasis is regulated by three hormones
parathyroid hormone
calcitriol
calcitonin
secreted by cells in the parathyroid gland ; essential for the maintenance of blood calcium levels within homeostatic levels
parathyroid hormones
increases blood calcium levels ; steroid hormone derived from vitamin D
calcitriol
secreted from C cells in the thyroid gland when blood calcium levels are too high
calcitonin
average adult has how many bones
206 bones
bones are segregated into two
axial skeleton
appendicular skeleton
how many bones does the skull have
22 bones
how many bones does the appendicular skeleton have
126
how many bones does the vertebral column have
26
how many bone does the thoracic cage have
25 bones
upper limbs, lower limbs, and two girdles
appendicular skeleton
two girdles
pectoral and pelvic
4 categories of bones based on their shape
long, short, flat, and irregular
longer than they are wide
long bones
wide as they are long ; help transfer force between long bones
short bones
relatively thin, flattened shape
flat bones
have shaped that do not fit readily into the three other categories ; specialized functions
irregular bones
hole in a bone
foramen
elongated hole ; tunnel like passage through a bone
canal or meatus
depression in a bone
fossa
rounded projection
tubercle or tuberosity
sharp projection from a bone ; most are sites of muscle attachment
process
smooth, rounded end of the bone, where it forms a joint with another bone is called
condyle
bending movement that decreases the angle of the joint to bring the articulating bones closer together
flexion
straightening movement that increases the angle of the joint
extension
usually defined as the extension beyond 180 degrees
hyperextension
movement of foot toward the plantar surface
plantar flexion
movement of foot toward the shin
dorsiflexion
movement away from the median or midsaggital plane
abduction
movement toward the median plane
adduction
palm is down
pronation
palm faces up
supination
turning the foot so plantar faces laterally
eversion
turning foot so that plantar faces medially
inversion
turning of a structure around its long axis
rotation
occurs at freely movable joints such as the shoulder
circumduction
glides anteriorly
protraction
glides posteriorly
retraction
