Skeletal System Flashcards
functions of skeletal system
support of body
protection of internal organs
levers for skeletal muscles to act
production of blood cells through bone marrow
storage of minerals
bone composition
composite material
- 70% calcium phosphate crystals (inorganic)
- 30% collagen fibres (organic)
remodels under influence of forces
calcium phosphate
strong but inflexible
ability to resist compressive stress
collagen
tough + flexible
ability to resist stretching, bending, + twisting stresses
anisotropic
bone (and wood) has different strength and hardness properties depending on its orientation
→ properties are different in different planes
mesenchymal cells
stem cells
undifferentiated
osteoprogenitor cells
stem cells - unspecialized mesenchymal cells
found in outer + inner layers of bone
differentiate into more specialized bone cells → osteoblasts
important role in fracture repair
osteoblasts
bone cells derived from osteoprogenitor cells
secrete osteoid
‘bone-producing cells’
osteocytes
osteoblasts that become trapped in hard bony tissue
mature bone cells
monitor + maintain protein levels + mineral contents of bony matrix
osteoclasts
large multinucleated bone cells
derived from precursor blood cells
secrete acids that erode bony matrix for release of amino acids + minerals in body fluids (blood)
osteiod
collageous material secreted from osteoblasts
unmineralized bone → will mineralize (calcify) to become bone
compact bone
relatively dense + solid
mainly found in diaphyses of long bones
spongy (trabecular) bone
open network of struts + plates
composed of trabeculae
interior bone tissue of short, flat, + irregular bones; epiphyses in long bones
endosteum
single layer of osteoblasts + fibrous tissue
inner layer (deeper tissue) lining medullary cavity
periosteum
single layer of osteoblasts + fibrous tissue
top outer layer (transparent)
medullary cavity
yellow marrow (adipocytes - fat)
+ red marrow (mature + immature red + white blood cells)
osteon
basic functional unit of mature compact bone
made up of Haversian systems: osteocytes organized in concentric layers around a central canal containing blood vessels
lamellae
parallel alignment of collagen into sheets to form calcified extracellular matrix
- concentric: concentric rings that form osteons
- circumferential: rings that line inner + outer surfaces of compact bone
- interstitial: areas of incomplete lamellae between osteons
lacunae
cavities between lamellae that contain osteocytes
trabeculae
irregular lattice arrangement of lamellae that surround red bone marrow
cartilage
type of connective tissue
dense network of collagen or elastic fibres
chondroblasts
deposit cartilage extracellular matrix
mature into chondrocytes
chondrocytes
sit in lacunae
found in cartilage
perichondrium
connective tissue covering surface of most cartilage
bone matrix
organic osteoid + inorganic hydroxyapatite (calcium phosphate + carbonate)
intramembranous ossification
develops from fibrous membrane
forms directly in mesenchyme
flat bones of skull + clavicle
- ossification centre
- calcification of matrix
- formation of trabeculae
- development of periosteum
ossification centre
deep inside membranous tissue
between periosteum and bone; where bone growth occurs
crowding of mesenchymal cells
endochondral ossification
bone replaces cartilage
in long bones
condensation of mesenchymal cells
growth
formation of primary + secondary ossification centres
interstitial growth
increase bone length
growth from within model
chondrocytes → cell division
secretion of more extracellular matrix
appositional growth
increase bone width
development of new chondrocytes from perichondrium → secrete new matrix
diaphysis
shaft of long bone
site of primary ossification centre
epiphysis
ends of long bone
site of secondary ossification centres
metaphysis
growth plates
junction between diaphysis and epiphyses where hyaline cartilage persists
resorption
local removal of bone + remodeling of bone surface by osteoclasts
decrease of bone width from inside
bone strength
orientation of stress influences bone’s ability to resist the stress
compression
push two ends together
bone is best at resisting
200 MN/m2 required to break
tension
pulling two ends apart
~135 MN/m2 required to break
shear
twisting to ends in opposite directions
easiest to break bone
~70 MN/m2 required to break
bone repair
- fracture hematoma formation
- fibrocartilaginous callus formation
- bony callus formation
- bone remodelling
bone remodeling
similar to appositional growth
balance between resorption + deposition of osteoclasts and osteoblasts
bone aging
hormonal changes affects balance between osteoblasts + osteoclasts
leads to osteoporosis
↓ ability of strain to resist stress = easier to break
osteoporosis
bone loss = low bone density
changes ability of bone to resist stress
long bone
ex. humerus
flat bone
ex. skull bones
two thin plates of compact bone separated by spongy bone
pneumatized bone
ex. ethmoid
air chambers within bone
irregular bone
ex. vertebrae
short bone
ex. carpal bones
bony features
elevations + projections
openings
processes for attachment
processes for articulation
depressions
crest
narrow prominent ridge
spine
sharp, pointed, narrow process
line
slightly raised, elongated, low ridge
trochanter
large rough projection
two massive bony processes on femur
tubercle
small rounded projection
tuberosity
rough projection for attachment of muscles
head
expanded articular end of an epiphysis
neck
narrower connection between head and shaft of long bone
facet
small flat articular surface
smooth, slightly concave or convex
condyle
smooth, rounded articular process
epicondyle
bony process superior to condyle
trochlea
condyle on humerus
shaped like pulley
sulcus
narrow groove
fossa
shallow, broad, or elongated depression
process
pointed, bony projection
ramus
extension of bone that forms angle with rest of structure
sinus
cavity in bone
canal
tubular passage through bone
meatus
opening of a canal
fissure
deep furrow, cleft, or slit
foramen
rounded passage through bone
fibrous joints
connected by dense connective tissue
allow very little movement
suture joint
synarthrotic fibrous joint = no movement
joined by sutural ligament
syndesmosis
amphiarthrotic fibrous joint = small degree of movement
joined by interosseous membrane
cartilaginous joints
two bones connected by hyaline cartilage
synchondrosis
primary cartilaginous joint
temporary cartilaginous union between bones
ossifies with age
symphysis
secondary cartilaginous joint
permanent cartilaginous union between bones
synovial joints
bones are joined by synovial cavity
contains synovial fluid to decrease friction
allows wide range of motion
ball and socket joint
motion in all planes
hinge joint
motion through one plane
condylar joint
motion through two planes
number of bones
skeletal system = 206
axial skeleton = 80
- skull = 29
- thoracic cage = 25
- vertebral column = 26
appendicular skeleton = 126
axial skeleton functions
support + protective framework for internal organs
skull houses special sensory organs
vertebral column + ribs provide extensive attachment for muscles moving head, neck, trunk + limbs
thoracic cage performs movements during respiration
neurocranium
skull
cranial bones: (1) frontal, (2) parietal, (2) temporal, (1) occipital, sphenoid, ethmoid
viscerocranium
skull
facial bones: (2) zygomatic, (2) lacrimal, (2) nasal, (2) palatine, (1) vomer, (2) maxilla, (1) mandible
skull suture joints
coronal = frontal + parietal
lambdoid = parietal + occipital
squamous = temporal + parietal
sagittal = left + right parietal
orbit
frontal + zygomatic + maxilla
sphenoid = back wall
- superior orbital fissure
- optic canal
ethmoid + lacrimal = medial wall
zygomatic arch
zygomatic + temporal
occipital bone
occipital condyles
foramen magnum
temporal bone
inferior
- carotid canal
- jugular foramen (between t + o bones)
lateral
- mastoid process
- mandibular fossa
- external acoustic meatus
sphenoid bone
pituitary gland
butterfly shaped
pneumatized bone
mandible
body
ramus
coronid process
mandibular condyle
temporomandibular joint
synovial
allows opening of jaw
mandibular fossa (t) + mandibular condyle (m)
cavities
cranial = brain
orbit = eyeball
nasal = drainage for air sinuses
oral = tongue
fontanelle
in infant skull = soft spot
membranous tissue between neocranium bones
will ossify to create sutures
vertebral column
7 cervical
12 thoracic
5 lumbar
5 sacral = sacrum
2-4 coccygeal = coccyx
curvatures
primary: thoracic + sacral
secondary: cervical + lumbar
vertebrae
vertebral body
pedicle (2)
transverse process (2)
spinous process
articular process (2 pairs =4)
vertebral foramen → together = canal (spinal cord + meninges)
intervertebral joint
intervertebral disc attached between two adjacent vertebrae
secondary cartilaginous joint
annulus fibrosus: outer cartilagenous ring
nucleus pulposus: gelatinous core
zygapophyseal joint
synovial joint between two adjacent articular processes
cervical vertebrae
transverse foramen - allows passage of vertebral artery
atlas
C1
arch
axis
C2
dens
atlanto-occipital joint
synovial joint between occipital condyles and C1
allows flexion of head up and down
atlanto axial joint
synovial joint between C1 and C2
allows head to turn side to side
thoracic cage
12 pairs of vertebrae→ ribs attach
sternum
costal cartilage - attach ribs to sternum
costovertebral joint
two synovial joints between thoracic vertebra and associated rib
lumbar vertebrae
large body
increase in size from 1 → 5
appendicular skeleton functions
daily tasks
adjustment of body posture
mobility of body
homologous between upper and lower limbs
pectoral/pelvic girdle
arm/thigh
forearm/leg
hand/foot
upper limb
pectoral girdle: scapula + clavicle
arm: humerus
forearm: ulna + radius
hand: carpal bones, metacarpals, phalanges
scapula
3 borders: vertebral (medial), axillary (lateral), superior
anterior: subscapular fossa
posterior: scapular spine, supraspinous fossa, infraspinous fossa
acromion
coracoid process
glenoid fossa
clavicle
s-shaped
sternal end forms sternoclavicular joint
acromial end forms acromioclavicular joint
both joints are synovial
humerus
head
greater + lesser tubercles
intertubercular sulcus
deltoid tuberosity
medial + lateral epicondyles
trochlea (medial condyle)
capitulum (lateral condyle)
olecranon fossa
ulna
trochlear notch
coronid process
olecranon
ulnar styloid process
radius
radial head
radial tuberosity
radial styloid process
carpal bones
scaphoid
lunate
triquetrum
pisiform
trapezium
trapezoid
capitate
hamate
5 metacarpals
14 phalanx
scapulothoracic joint
scapula is only attached to thoracic wall by muscle (not actual joint)
clavicle links acromion and sternum
movements:
- elevation/depression (shrug shoulders)
- retraction/protraction
glenohumeral joint
ball + socket
weak joint capsule → reinforced by rotator cuff (4 shoulder muscles)
elbow joint
2 joints
- humeroulnar joint: hinge between trochlea and trochlear notch → allows flexion/extension
- humeroradial joint: condylar between capitulum + radial head → allows pronation/supination
forearm interosseous membrane
fibrous joint between ulna and radius
prevents separation
muscle attachment
wrist joint
more than one
main: condylar joint between radius and scaphoid
allows flexion/extension + abduction/adduction of hand
thumb joint
saddle-shaped
between trapezium + 1st metacarpal
allows for opposition of thumb
lower limb
pelvic girdle: L+R ossa coxae + sacrum
thigh: femur
leg: tibia + fibula
foot: tarsal bones, metatarsals, phalanges
os coxae
ilium
- iliac crest
- anterior superior iliac spine
- iliac fossa
- greater sciatic notch
- auricular surface
ischium
- ischial spine
- ischial tuberosity
pubis
- pubic symphysis
acetabulum
femur
head
neck
greater + lesser trochanter
intertrochanteric line
gluteal tuberosity
linea aspera
medial + lateral condyles
patellar surface
tibia
medial + lateral condyles
tibial tuberosity
medial malleolus
fibula
fibular head
lateral malleolus
tarsal bones
calcaneous
talus
navicular
cuboid
cuneiforms (3)
5 metatarsals
14 phalanx
hip joint
ball + socket
reinforced anteriorly by iliofemoral ligament
knee joint
largest synovial
hinge
allows flexion + extension of leg
quadriceps tendon (patella + quadriceps femoris)
patellar ligament (patella + tibia)
meniscus
knee ligaments
lateral + medial collateral ligaments
anterior + posterior cruciate ligaments
lateral + medial menisci
leg interosseous membrane
fibrous joint between tibia + fibula
prevents separation
ankle joint
hinge between tibia + talus
allows plantarflexion + dorsiflexion of foot
foot joint
condylar
between talus + navicular
allows inversion/eversion of foot
