skeletal system real not fake #realnotfake

bone is one of the ______________ in the human body

hardest matierals

Bone is relatively ________ and has the ability to __________

light weight; resist tension

Bone acts as a strong _______ while retaining its ________

support system; mobility

The _____________ deposited in its matrix give bone its hardness and ability to resist _______________

calcium salts; compression

the ________ parts of the bone provide flexibility and great ______________-

organic; tensile strength

parts of the skeletal system:

- bones (skeleton)

- joints

- cartilages

- ligaments

two subdivisions of skeleton

axial and appendicular

axial skeleton

skull, vertebral column, thorasic cage

appendicular skeleton

shoulder girlde, upper limbs, pelvic girdle, and lower limbs

skull and vertebrae protect the

brain and spinal cord

muscles use the bones as ______ to move the body and its parts

levers

_____ and ______ are stored in the bone matrix

calcium and phosphorus

calcium ions must be present in the blood stream to allow

nerve impulses to travel and muscles to contract

_____ is stored in the internal marrow cavity of the bone

fat

hematopoiesis occurs in the

marrow of certain bones

the adult skeleton has ____ bones

206

bones are classified in two ways:

spongy and compact

compact bone:

dense, looks smooth, and homogeneous

spongy bone:

composed of small needlelike piece of bone with many open spaces (bone marrow may fill some of those spaces)

bone shapes:

long, short, flat, irregular

long bones are

typicallly longer than they are wide

composed of a shaft w rounded heads at both ends

mostly compact bone

all of the bones of the limbs (exc wrist ankle and knee caps)

short bones are

generally cube shaped

mostly spongy bone

bones of wrists and ankles

sesamoid bones

type of short bone which forms within tendons

flat bones

thin, flattened, usually curved

two thin layers of compact bone surrounded by a layer of spongy bone

irregular bones

irregular shaped bones

does not fit into either category

ex : sphenoid

diaphysis/shaft

makes up most of the bones length

periosteum

covers the diaphysis/shaft in a fibrous connective tissue membrane

perforating or sharpey's fibers

secure the periosteum to the underlying bone

epiphysis

ends of the long bone

composed mostly of spongy bone enclosed by a thin layer of compact bone

articular cartilage

covers external surface of epiphyses

made of hyaline cartilage

provides a smooth, slippery surface which decreases friction at joint surfaces

epiphyseal plate

flat plate of hyaline cartilage seen in young, growing bones

allows lengthwise growth of the long bones up until puberty, then completely converted to long bone

epiphyseal line

seen in adult bones

a thin smooth line of bony tissue spanning the epiphysis that is the remnant of the epiphyseal plate

medullary cavity

cavity inside the shaft

in adults, it contains yellow marrow

in kids, it contains red marrow

in adults, red marrow is situated in cavities of spongy bone

endosteum

a thin layer of connective tissue that lines the surface of the bony tissue that forms the medullary cavity of long bones

arteries

supplies bone cells w nutrients

bone markings are the results of:

attachment sites for muscles, tendons, and ligaments

passageway for nerves and blood vessels

projections or processes

grow out of the bone surface; often terms start with T

depressions or cavities

indentations of the bones; terms often begin with F

osteon

a unit of bone containing central canal and matrix rings

central canal

opening in the center of an osteon

carries blood vessels and nerves

perforating (volkmann's) canal

canal perpendicular to the central canal that runs in between the osteum

carries blood vessels and nerves

lacunae

Cavities containing bone cells (osteocytes)

Arranged in concentric rings

lamellae

rings around central matrix

has lucunae

canaliculi

tiny canals

radiate horizontal from the central canal to lacunae

form a transport connecting all bone cells to a nutrient supply

free bee

yay

in embryos, the skeleton is primarily ____________

hyaline cartilage

during development, hyaline cartilage is often replaced with

bone tissue

after childhood, cartilage only remains in

the bridge of the nose, ribs to sternum, and joints & articular cartilage

flat bones from within

fibrous membranes

three types of bone cells

osteocytes

osteoblasts

osetoclasts

osteocytes

mature bone cells

osteoblasts

bone forming cells

osteoclasts

giant bone destroying cells

the bone matrix can be broken down in order to release ____ in response to the _________

calcium, parathyroid horomone

ossification

bone growth

ossification involves two major phases

first: the hyaline cartilage is completely covered with bone matrix by bone forming cells called osteoblasts

second: the enclosed cartilage is digested away, opening up a medullary cavity within the newly formed bone allowing blood vessels to enter the bone

most hyaline cartilage is converted to bone tissue except

articular cartilage (covers the ends of the bones)

epiphyseal plates (allow for lengthwise growth of long bones during childhood)

where is new cartilage constantly being formed

external surface on the articular cartilage and epiphyseal plate surface that faces the bone end

old cartilage is broken down and replaced by

bony matrix

how do bones grow during childhood

the osteoblasts in the periosteum add bone tissue to the diaphysis as osteoclasts in the endosteum remove bone from the diaphysis

both creating new bone tissue and destroying old bone tissue during puberty happens ______

at the same time

the process of long bone growth is controlled by

growth horomones and sex horomones

bone continues to lengthen until

puberty ends

true or false: bone is a dynamic and active tissue

true

when calcium levels are low in the blood, the _______ are stimulated to release ____ into the blood stream which signals the osteoclasts to break down bone matrix relasing ____ into the blood

parathyroid glands, PTH, CA ions

as the body increases in size,

areas of bone become thicker and form projections to increase their strength

closed (simple) fracture

a break that does not penetrate the skin

open (compound) fracture

a broken bone that penetrates through the skin

comminuted

break into many fragments, typically 2 or more pieces

compression

bone is crushed