Parts of the skeletal system
Bones (skeleton)JointsCartilagesLigaments
Two divisions of the skeletal system
Axial skeletonAppendicular skeleton
Five primary Functions of the Skeletal System
SupportStorage of Minerals (calcium) and Lipids (yellow marrow)Blood Cell Production (red marrow)ProtectionLeverage and Motion
Adult skeleton has ___ bones
206
Two basic types of bone tissue
Compact boneSpongy bone
Compact Bone
Hard
Spongy Bone
Bone tissue that consists of an open network of struts and plates that resembles latticeworkInner layer of most bones and ends of epiphysis of long bones
Bones are classified by
ShapeInternal tissue organizationBone markings (surface features
marks)
Six bone shapes
Flat bonesLong bonesIrregular bonesSutural bonesSesamoid bonesShort bones
Sutural Bones
Small
Irregular Bones
Have complex shapesEx: spinal vertebrae and pelvic bones
Short bones
Small and thickEx: ankle and wrist bones
Flat bones
Thin with parallel surfaces
Flat bones are found in ___
skull
Long bones
Long and thin
Long bones are found in ___
arms
Sesamoid bones
Small and flat
Sesamoid bones develop inside ___
tendons near joints of knees
Depressions or grooves are found along
bone surface
Elevations or projections
Where tendons and ligaments attachAt articulations with other bones
Tunnels
Where blood and nerves enter bone
Structure of a long bone
DiaphysisEpiphysisMetaphysis
Diaphysis
The shaftA heavy wall of compact bone
Epiphysis
Wide part at each endArticulation with other bonesMostly spongy (cancellous) boneCovered with compact bone (cortex)
Metaphysis
Where diaphysis and epiphysis meet
Osteon (Haversian System)
A unit of bone
Central (Haversian) canal
Run lengthwise in long bonesCarries blood vessels and nerves
Perforating (Volkman's) canal
Canal perpendicular to the central canalCarries blood vessels and nerves
Lacunae
Cavities containing bone cells (osteocytes)Arranged in concentric rings
Lamellae
Rings around the central canalSites of lacunae
Canaliculi
Allow for transportRadiate from the central canal to lacunae
Yellow Bone Marrow
has adipose tissue (fat) that stores energy
Red Bone Marrow
forms blood cells (hematopoiesis)
Bone cells make up ___% of bone mass
2
Four types of cells in bones
OsteocytesOsteoblastsOsteogenic cellsOsteoclasts
Osteocytes
bone cells
Osteoblasts
bone forming cells
Osteogenic cells
stem cells
Osteoclasts
Bone-destroying cells
In embryos
the skeleton is primarily ___ cartilage
During development
most hyaline cartilage is replaced by ___
Cartilage remains in isolated areas:
Bridge of the noseParts of ribsJoints
Human bones grow until about age ___
25
Osteogenesis
Bone formation
Ossification
The process of replacing other tissues with bone
Calcification
The process of depositing calcium saltsOccurs during bone ossification and in other tissues
Two main forms of ossification
Endochondral ossificationIntramembranous ossification
Endochondral Ossification
Ossifies bones that originate as hyaline cartilageMost bones originate as hyaline cartilageThere are seven main steps in endochondral ossification
Intramembranous (dermal) Ossification
Occurs in the dermisProduces dermal bones such as mandible (lower jaw) and clavicle (collarbone)
Types of bone fractures
Closed (simple) fractureOpen (compound) fracture
Closed (simple) fracture
Break that does not penetrate the skin
Open (compound) fracture
Broken bone penetrates through the skin
Types of Fractures
DisplacedEpiphysealCollesCompressionComminutedGreenstickTransverseSpiralPott's
Transverse
break a bone shaft along its long axis
Displaced
produce new and abnormal bone arrangements
Compression
occur in vertebrae subjected to stress
Spiral
produced by the twisting stresses along the length of the bone
Epiphyseal
tend to occur where the bone matrix is undergoing calcification
Comminuted
shatter the affected area into many fragments
Greenstick
only one side of broken
Colles
break in distal portion of the radius
Pott's
occurs at ankle
Repair of bone fractures
Fracture hematoma formation2. Callus formation3. Spongy bone formation4. Compact bone formation
Fracture hematoma formation
blood-filled swelling is formed
Callus formation
break is splinted by fibrocartilage to form a callus
Spongy bone formation
fibrocartilage callus is replaced by a bone callus
Compact bone formation
bone callus is remodeled to form a permanent patch
Osteoporosis
Severe bone lossAffects normal functionOver age 45
Axial skeleton
Forms the longitudinal part of the bodyDivided into three parts
Three parts of axial skeleton
SkullVertebral columnBony thorax
Skull
Protects the brain
Skull contains
22 bones8 cranial bones14 facial bones
Cranial bones
form the braincase
Facial bones
protect and support entrances to digestive and respiratory tracts
Sinuses
Cavities that decrease the weight of the skullLine with mucous membranesProtect the entrances of the respiratory system
Fetal skull
large compared to the infants total body lengthallows the brain to growconverts to bone within 24 months after birth
3 parts of sternum
manubrium
Fontanelles
fibrous membranes connecting the cranial bones
Vertebrae
Separated by intervertebral discs
Spinal curves
Cervical curveThoracic curveLumbar curveSacral curve
Cervical curve
a secondary curve
Thoracic curve
a primary curve
Lumbar curve
a secondary curve
it develops with the ability to stand.L1 - L5
Sacral curve
a primary curve
Coccyx
4 fused vertebrae
Bony thorax
Forms a cage to protect major organsMade up of three parts
Three parts that make up the bony thorax
SternumRibsThoracic vertebrae
Appendicular Skeleton
126 bonesAllows humans to move and manipulate objectsIncludes all bones besides axial skeleton
The supportive girdles
pectoralpelvic
Pectoral (shoulder) girdle
Clavicle (collarbone)Scapula (shoulder blade)
Clavicle and scapula allow ___
Allows the upper limb to have exceptionally free movement
The arm is formed by ___
Humerus
Forearm is formed by ___
UlnaRadius
Hand is formed by
Carpals (wrist)Metacarpals (palm)Phalanges (fingers)
Pelvic Girdle
Hip bonesThe total weight of the upper body rests on the pelvisProtects several organs
Pelvic Girdle is composed of three pair of fused bones
IliumIschiumPubic bone
Organs that the pelvic girdle protects
Reproductive organsUrinary bladderPart of the large intestine
The thigh has ___
Femur