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Organs of the skeletal system composed of many tissues
bones
bones provide a point of attachment for
muscles
bones vary in
shape and size
bones are similar in
structure, development, and function
mature bones cells are called
osteocytes
osteocytes occupy chambers called
lacunae
osteocytes exchange nutrients and waste through a passage called
canaliculli
compact bones consists of units called
osteons
spongy bones consist of branching plates called
trabeculae
skeletal system beginas to develop
within first few weeks
bones form when tissue places existing connective tissue in (two ways)
as intramembranous bones
as endochondral bones
flat skull bones that form between sheets of primitive connective tissue
intramembranous ossification
long bones and most of skeleton are forming from hyaline cartilage models
endochondral ossification
intramembranous ossification is the process of
replacing connective tissue to form intramembranous bone
bone forming cells that deposit bone matrix around themselves
osteoblasts
osteoblasts become surrounded by matrix and become
osteocytes in lacunae
most bones of the skeleton are
endochondral bones
the process of replacing hyaline cartilage to form an endochondral bone is
endochondral ossification
during endochondral ossification matrix
breaks down and chondrocytes die
osteoblasts form ________ and then _______ bone
spongy, compact
once encased by matrix, osteoblasts are now ________
osteocytes
diaphysis is separated by epiphysis by
epiphyseal
layer closest to epiphysis
zone of resting cartilage
what zone brings growth
hypertrophic
osteoblasts invade and replace cartilage with
bone tissue
what allows a bone to grow in length
epiphyseal plate
do babies have more osteoblasts or osteocytes?
osteoblasts
removal of bone, action of osteoclasts is
bone resorption
formation of bone, action of osteoblasts (making more bone) is
bone deposition
how much of the skeleton is replaced each year?
10% - 20%
what are characteristics that affect bone development
nutrients, sunlight, exposure, hormone levels, and physical exercise
what simulates cartilage cell division?
growth hormones
what simulates bone growth?
physical stress
a fracture protected by uninjured skin
simple (closed) fracture
fracture in which the bone is exposed to the outside through opening in skin
compound (open) fracture
list the steps in order of fracture repair:
remodeling
cartillaginous
hemotoma
bony
hemotoma
cartillaginous
bony
remodeling
the bone provides ______, _______, and ______ to the body
shape, support, and protection
skull bones protect (3)
brain, ears, eyes
bones of rib cage protect (2)
heart and lungs
what provides movement?
bones and muscles
red bone marrow is replaced by ______ bone marrow, which stores ____ but does not produce blood cells
yellow, fat
what is the most abundant salt?
hydroxyapatite
osteoporosis results from
loss of bone mineralization
what is the term for bone loss
osteopenia
what is the condition for bone loss that leaves spaces and canals and weakens them?
osteoporosis
each adult has ______ bones
206
any time 2 bones come together
joint
what is another word for joint?
articulations
how moveable is synarthrotic?
immovable
how moveable is amphiarthrotic?
slightly movable
how moveable is diachronic?
freely movable
between the tibia and fibula, flexible, bones bound by tissue or a bundle of dense connective tissue
syndesmosis
between flat bones of skull and thin layer of connective tissue, immovable
suture
in jawbone, immovable
gomphosis
cartilage joints are connected by
hyaline cartilage or fibrocartilage
most joints are ______ joints
synovial
synovial joints are all _______ joints
diarthrotic joints
outer fibrous layer is composed of
ligaments
inner fibrous layer secretes
synovial fluid
ball-and-socket joint movements are
rotation
condylar joints movements are
back and forth/side to side
plane joint movements are
back and forth/twisting
what is the result of skeletal muscle actions
movements at synovial joints
what is used to replace joints damaged by arthritis or injury
synthetic materials
why do older people decrease in height?
water loss from the intervertebral discsw
what keeps joints functional for longer?
activity and exercise
synovial joints loose function as __________ ______ diminishes
capillary supply
what does Atlas C1 do?
supports head
what does axis C2 do?
pivots around
What bones do the axial skeleton contain? and how many bones?
skull, middle ear bone, hyoid bone, vertebral column, and thoracic cage; 80 bones
what bones does the appendicular contain? how many bones?
pectoral girdle, upper limbs, pelvic girdle, lower limbs; 120 bones