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function of bone

muscle attachment,protection and support, blood cell production and support and storage of materials

epiphysis

parts of the long bone that are expanded ends of bones that form joints with adjacent bones

articular cartilage

covers the epipiphyses and made of hyaline cartilage

diaphysis

shaft of the bone

periosteum

tough layer of vascular connective tissue that covers the bone and is continuous with ligaments and tendons, functions in the formation and reparation of bone tissue, forms by cells of the membranous connective tissue that lie outside the developing bone

a bone's shape

makes possible its function

bony processes or projections

sites of attachment for ligaments and tendons

compact bone

makes up the wall of diaphysis and is made of osteocytes, osteons, that contain blood vessels and nerve fibers lots of matrix arranged around osteonic canals etc..

spongy bone

fills the epiphysis and reduces the weights of the skeleton ( more at ends of bones), more space, no osteocytes, less matrix, not arranged around osteonic canals

medullary cavity

hollow cavity in diaphysis lines with endosteum and filled with marrow (tissue)

bones are classified

by bone shape

long bones

longitudinally long, expanded ends. example = forearm, thigh

short bones

cube-like, equal width and length. example= bones of wrists and ankles

flat bones

plate-like with broad surfaces. example= ribs, scapulae, some cranial

irregular bones

various shapes, but usually connected to other bones. example= facial bones, vertebrae

sesamoid bones

round,small and nodular. example= kneecap

osteocytes

bone cells

lacunae

spaces where osteocytes are

osteonic ( central ) canals

osteocytes within lacunae lie in concentric circles around these

matrix

osteocytes pass nutrients and gases in the this through canaliculi, consists of collagen and inorganic salts

canaliculi

extends of cell membrane or osteocytes cell processes

perforating canal

osteonic canals that are interconnected by transverse _________

osteonic canals

contain blood vessels and nerve fibers and extend longitudinally through the bone

intramembranous bones

form by the formation of bone within sheetlike layers of connective tissue (unspecialized)

endochondral bones

form by replacing connective tissues ( hyaline cartilage) in the fetus

example of intramembranous bones

skull

osteoblasts

deposit bony tissue around themselves

osteocytes

once osteoblasts deposit bone and are located in the lacunae, they are called this

ossification

formation of bone

primary ossification center

formation of spongy bone where cartilage is replaced by spongy bone in the diaphysis cartilage is broken down in the diaphysis and progessively develops on the outside, cartilage tissue is invaded by blood vessels and osteoblasts that first form spongy bone at the primary ossification center (most bones) and osteoblasts beneath the periosteum lay down compact bone on the outside of spongy bone

secondary ossification center

appears later in ossification in the epiphysis, the epiphyseal plate forms between the two ossification centers, osteoclasts break down the calcified matrix and are replaced with bone-building osteoblasts that deposit bone in place of calcified cartilage. a medullary cavity forms in the region of the diaphysis due to the activity of the osteoclasts

epiphyseal plate

a band of hyaline cartilage between the two ossification centes and is a layer of cartilage cells undergoing mitosis. it is responsible for lengthening bones

increase in bone thickness due to

intramembranous ossification underneath the periosteum

osteoclasts

tear down

osteoblasts

build bone throughout the lifespan with the processes of resorption and deposition with an average of 3-5% of bone calcium exchanged annually by the good blood supply ( mass remains relatively constant)

bone function

support and protection, give shape to head, thorax, and limbs. pelvis bones give support, skull protects the brain, ears, and eyes

lever

has four components, a rigid bar, a pivot or fulcrum ( point of connection), an object that is moves against resistance, and a force( from muscle) that supplies energy

blood cell formation

begins to form through hematopoieses in the yolk sac and later in the bone marrow

red marrow

functions in the formation of red blood cells, white blood cells, and platelets, and is found inthe spongy bone of the skull, ribs, sternum, clavicles, vertebrae, and pelvis

yellow marrow

occupying the cavities of most bones, stores fat

storage of inorganic salts

the inorganic matrix of bone stores inorganic mineral salts in the form of calcium phosphate that is important in many metabolic processes

calcium in the bone functions as

a reservoir for body calcium, when blood levels are low, osteoclasts release calcium from the bone ( important in nerve impulses, muscle contractions, and blood clotting)

calcitonin

hormone secreted by the thyroid when calcium levels in the blood are too high and causes calcium to be stored in the bone

bone stores ___ outside of calcium

magnesium, sodium, potassium, and carbonate ions ( used in metabolic processes, maintianing homeostasis, and active transport in cells)

harmful elements that bone can accumulate

lead, radium, and strontium

if calcium levels in the blood are too high

cells in the thyroid gland sense the increase in the blood calcium concentration and the thyroid gland releases calcitonin, osteoblasts then deposit calcium in the bones to return to normal ( as calcium phosphate)

if calcium levels in the blood are too low

cells in the parathyroid gland sense the decrease in blood calcium, then release a parathyroid hormone causing osteoclasts to break down bone to release calcium

changes in blood calcium concentration occur by

dietary, hormonal, or genetic issues

an issue of the thyroid may be diagnosed by

off calcium concentrations

axial skeleton

consists of the skull , vertebral column and thorax

appendicular skeleton

consists of the pectoral girdle, upper limbs, pelvic girdle, lower limbs

skull

made up of 22 bones, 8 cranial an 13 facial and the mandible

cranium

encloses and protects the brain, provides attachments for muscles, and contains air-filled sinuses that reduce its weight

frontal bone

includes the supraorbital foramen and frontal sinuses

suture

union between bones

foramen

passageway for blood vessels and nerves in the skull

parietal bones

lie at the sides of the skull and join at the sagittal suture

occipital bone

include the lambdoidal suture, foramen magnum, and occipital condyles

temporal bone

includes the squamosal suture, external acoustic meatus, mandibular process, styloid process (opening in ear) and zygomatic process

sphenoid bone

includes the sphenoidal sinuses

ethmoid bone

includes the ethmoidal sinuses

facial skeleton

includes 13 immovable bones and the mandible to form the basic face and provide attachments for muscles of mastication and expression

maxillae

forms the upper jaw, hard palate, floor of the orbits, sides of the nasal cavity, house the upper teeth, and contain large maxillary sinuses

palatine bones

L-shaped and found behind the maxillae that form the floor of the nasal cavity and hard palate

zygomatic bones

make up the cheekbones and join with the temporal bones to form the zygomatic arches

lacrimal bones

form part of the medial walls of the orbits

nasal bones

form the bridge of the nose

vomer bone

makes up the portion of the nasal septum

inferior nasal conchae

fragile, scroll-shaped bones that support mucous membranes within the nasal cavity

mandible

lower jawbone, supports the lower teeth and includes the mandibular condyle, coronoid process, and alveolar arch

cervical vertebrae

the seven bones are the smallest of the vertebrae that comprise the neck and the support of the head, have a bifid spinous process and transverse foramina

atlas

first vertebra and looks like a bony ring to support the head, side side and up down movement

axis

second vertebra with tooth-like dents that pivot within the atlas

thoracic vertebrae

twelve vertebrae that articulate with the ribs, larger and stronger that cervical

lumbar vertebrae

five massive vertebrae that support the weight of the body ( main)

sacrum

triangular strucutre at the base of the vertebral column made up of five vertebrae fused into one bone ( spinous processes are fused to form a ridge of tubercules that have a dorsal sacral foramina along their sides, 4 on each side)

coccyx

lowermost portion of the vertebral column and is composed of four fused vertebrae

thoracic cage

includes the ribs, thoracic vertebrae, sternum, and costal cartilages, support the pectoral girdle and upper limbs, functions in breathing and protects the thoracic and upper abdominal organs

ribs

normally there are 12 pairs of ribs that attach to thoracic vertebrae, the first seven pairs are vertebrosternal and the remaining five pairs are false ribs, the first three of theses are vertebrocondral, the last two of these are floating ribs

typical rib

includes a shaft, costal groove, anterior end ( sternal), head, neck, and tubercle ( head articulates with the vertebrae, tubercle with the transverse process of the vert)

sternum

located along the anterior midline of the thoracic cage, includes upper manubrium, middle body, and lower xiphoid process

pectoral girdle

makes and incomplete ring that supports the upper limbs, includes a two scapulae and two clavicles

clavicles

elongated s-shaped bones located at the base of the neck that function to brace the scapulae

scapulae

flat, triangular bones on either side of the upper back, spine divides it into unequal portions

upper limb

bones of the upper limb form the framework for the arm, forearm, and hand

humerus

makes up the upper arm, extending from the scapula to the elbow and articulates with the scapulae at its head with the radius at the capitulum and the ulna at the trochlea

radius

located on the thumb side of the forearm, extending from the elbow to the wrist, pivots with the humerus

ulna

longer of the two bones making up the forearm and had a trochlear notch that articulates with the humerus

wrist

made up of 8 carpal bones bound into a carpus

hand

made up of 5 metacarpal bones

fingers

made up of groups of three phalanges in each finger, except the thumb which lacks a middle phalanx

fissure

narrow slit-like opening between adjacent parts of bones through which blood vessels and nerves may pass

canal

tube-like passageway

meatus

canal-like

sinus

air-filled cavity within a bone that connects to the nasal cavity

process

prominent projection of a bone that may be articulating or non

condyle

articulating, large, knuckle-like projection

articulate

in contact or coordination between bones

head

rounded articulates

tubercle

small, knob-like and non

epicondyle

smaller projection above condyle non

facet

smooth , flat surface, arti

trochanter

blunt projection non

hip bone

made up of three bones, the ilium, ischium, and pubis that are fused in the region of the acetabulum

acetabulum

cup-like depression that articulates with the head of the femur

ilium

largest and most superior portion of the hip bone and joins the sacrum at the sacroiliac joint

ischium

forms the L-shaped portion that supports weight during sitting

pubis

comprises the anterior portion of the coxal bones and articulates at the symphysis pubis

obturator foramen

lies within each pubis

greater pelvis

above the pelvic brim ( lesser pelvis is below it)

lower limb

bones here provide the framework for the thigh, lower leg, and the foot

femur

thighbone that extends from hip to the knee and is the longest bone in the body

patella

kneecap that is located in the tendon that passes over the knee

tibia

shinbone that supports the weight of the body and articulates with the femur and with the tarsal bones

fibula

slender bone lying lateral to the tibia and it does not bear body weight

ankle

composed of seven tarsal bones to form the tarsus

talus

articulates with the tibia and fibula and is found in the ankle

calcaneus heel

found in ankle and supports the body weight

instep of foot

consists of five metatarsal bones and provides an arch

toes

made up of phalanges

joints classified by

degree of movement possible, slightly movable, or freely movable or by the type of tissue that binds them together

fibrous joints

are held together by dense connective tissue and are immovable or only slightly movable

example of fibrous joint

suture of skull, between tibia and fibula

cartilaginous joints

made up of hyaline cartilage or disks of fibrocartilage

example of cartilaginous joint

symphysis pubis and first rib of sternum or intervertebral disks

synovial joints

most complex joint made up of hyaline cartilage, joint capsule of an outer layer of dense connective tissue that joins the periosteum and inner synovial membrane which includes synovial fluid, some contain menisci ( shock absorbing pads), or bursae ( fluid-filled sacs)

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