Anatomy Skeletal System and Joints

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