Skeletal System

206 Total Bones

Mr. VazquezMater Lakes Academy2011 – 2012Biology

Functions of the Skeletal System• Support and protection

• Blood cell formation

• Mineral Storage

• Site for muscle attachmentbody movement

Types Of JointsPivot Hinge

Ball & Socket Gliding

Top of the neck

Shoulder/Hip

Elbow/Knee

Intercarpal joints

Cranium

Mandible

Sternum

Rib

Vertebral ColumnPelvisSacrum

Coccyx

Clavicle

Scapula

Humerus

Ulna

Radius

Carpals

Metacarpals

PhalangesFemur

Patella

Tibia

Fibula

TarsalsMetatarsals

Phalanges

Types of Bones

• Long Bone • Short Bone

• Flat Bone • Irregular Bone

Head – Body - Head As wide as they are long

Provides Protectionbones which do not fall into any other

category

Connective Tissues• Cartilage – • Allows joints to move easily, cushions

bones, and supports soft tissue

• Ligament – • Hold bones in place at the joints

• Tendon – • Joins muscle to muscle or muscle to bone

Skeletal System Information

Appendicular

System

126 bones

Axial System

80 bones

Bone enclosed in periosteum, which is continuous with tendons and ligaments blood vessels in periosteum

Epiphysis- endsspongy bone contains red marrowcompact bone, articular cartilage

Diaphysis- middle compact bonemedullary cavity- contains yellow

marrow (fat)lined with endosteum (squamous

epithelium)

Compact bone osteocytes within lacunae are arranged in concentric circles called lamellae

This surround a central canal; complex is called the Haversian system

Canaliculi connect osteocytes to the central canal and to each other

Axial skeletonskull (cranium and facial bones)hyoid bone (anchors tongue and muscles associated with

swallowing)vertebral column (vertebrae and disks)thoracic cage (ribs and sternum)

Appendicular skeletonpectoral girdle (clavicles and scapulae)upper limbs (arms)pelvic girdle (coxal bones, sacrum, coccyx)lower limbs (legs)

22 bones in skull6 in middle ears1 hyoid bone26 in vertebral column25 in thoracic cage

4 in pectoral girdle60 in upper limbs60 in lower limbs2 in pelvic girdle

206 bones in all

The skull

8 sutured bones in craniumFacial bones: 13 sutured bones, 1 mandible

Craniumencases brainattachments for

muscles and sinuses

Vertebral column

7 cervial vertebrae12 thoracic5 lumbar1 sacrum (5 fused 1 coccyx (4 fused)

Vertebrae vary in size and morphology

Thoracic cageribsthoracic vertebraesternumcostal cartilages

True ribs are directly attached to the sternum(first seven pairs)Three false ribs are joined to the 7th ribTwo pairs of floating ribs

Clavicles and scapulae

Help brace shouldersAttachment sites for muscles

Bones of upper limb

Humerus (upper arm)Radius; ulnaCarpals, metacarpals, phalanges

Bones of lower limb

FemurPatellaTibia, fibulaTarsals, metatarslas, phalanges

Joints

Immovable (synarthoses) bones sutured together by connective tissue: skull

Slightly movable (amphiarthoses) connected by

fibrocartilage or hyaline cartilage: vertebrae, rib/sternum joint, pubic ymphysis

Freely movable (diarthroses)- separated ligaments- hold bones togethertendons- muscle to bone

lined by synovial membrane

Types of freely movable joints

Saddle: carpal and metacarpal bones of thumb

Ball and socket: shoulder and hip joints

Pivot- rotation only: proximal end of radius and ulna

Hinge- up and own movement in one plane:knee and elbow

Gliding- sliding and twisting: wrist and ankle

Condyloid- movement in different planes but notrotations: btw metacarpals and phalanges

Types of movement and examples (with muscles)flexion- move lower leg toward upperextension- straightening the leg

abduction- moving leg away from bodyadduction- movong leg toward the body

rotation- around its axissupination- rotation of arm to palm-up positionpronation- palm down

circumduction- swinging arms in circles

inversion- turning foot so sole is inwardeversion- sole is out

Elevation and depression- raising body part upor down

Aging and bonesboth bone and cartilage tend to deterioratecartilage: chondrocytes die, cartilage becomes calcified

osteoporosis; bone is broken down faster than it can be builtbones get weak and brittle; tend to fracture

easily

Growth hormone regulates skeletal growthstimulates cell division in epiphyseal disksin long bones

Growth stops when epiphyseal disks are converted to bone

When excess growth hormone is produced inchildhoodgigantism

In adulthood- acromegaly. Bones can’t growbut soft tissue can

Open Fracture

a fracture that protrudes to the exterior of the body.

Closed Fracture

A Fracture that does not break the skin

Greenstick Fracture

Only one side of the bone is broken, mostly seen in children

Transverse Fracture

Break at a right angle and caused by direct traumatic injury

Spiral Fracture

Bone broke because of a twisting type motion.

Oblique Fracture

Rarest form of fractures, the break is at an angle.