SKELETAL SYSTEM

- support and protection
- body movement - muscles "pull" on bones
- blood cell formation- hemopoiesis - occurs in red bone marrow
- storage of inorganic salts - calcium, magnesium, sodium, potassium...

Organization

- normally 206 bones with 2 Main Divisions: ____________ & _____________

1. AXIAL: head, neck, trunk
2. APPENDICULAR: limbs and bones connecting the limbs to the:
     bone anatomy - pectoral girdle (scapula & clavicle), upper limbs (arms)
      - pelvic girdle (coxal bones), lower limbs (legs)

Bone Structure:

1. EPIPHYSIS - ends of bone, articulates (forms a joint) with another bone.
2. DIAPHYSIS - shaft of the bone
3. ARTICULAR CARTILAGE - hyaline cartilage covering the ends of bones
4. PERIOSTEUM - tough membrane-like covering over entire bone.
5. MEDULLARY CAVITY - hollow chamber within the diaphysis, contains bone marrow
     ENDOSTEUM - lining of the medullary cavity

      - Red Marrow - mainly in spongy bone in adults, produces blood cells
      - Yellow Marrow - fat storage

Two Types of Bone Tissue

1. COMPACT (cortical) bone- wall of the diaphysis, solid, strong
2. SPONGY (cancellous) bone - epiphysis.

Microscopic Structure

- MATRIX composed of collagen and inorganic salts
- OSTEOCYTES (mature bone cells) are enclosed in tiny chambers called LACUNAE which form concentric rings called LAMELLA
- CANALICULI (canaliculus) connect the osteocytes
- HAVERSION CANALS & VOLKMANN'S CANALS provide passageways for blood vessels.

Bone Development and Growth:

1. Intramembranous bones = broad, flat bones of the skull

2. Endochondral bones = all other bones.

Bones first form as hyaline cartilage. The cartilage then gradually changes into bone tissue - a process called ____________________________,

primary ossification center - diaphysis, increase diameter
secondary ossification center - epiphysis, increase length
epiphyseal disk ( growth plate) between the diaphysis and the epiphysis.

_____________________- produce bone cells called OSTEOCYTES
_____________________ - dissolve bone tissue - a process called RESORPTION. .

3 Basic Types of Joints (articulations):

1. SYNARTHROTIC - immoveable joint, these junctions are called sutures.
2. AMPHIARTHROTIC - slightly moveable joint, vertebrae
3. DIARTHROTIC - freely moveable joint, have a lubricating fluid called synovial fluid.

                        Ball & Socket       |     Hinge      |      Pivot      |           Saddle

Examples:

skullBones of the Skull

1. Frontal - anterior portion above eyes
2. Parietal - one on each side of the skull,  just behind frontal bone
3. Occipital - forms the back of the skull and base of the cranium
4. Temporal - forms parts of the sides and base of cranium
5. Sphenoid - within the cranium, partly visible in eye socket
6. Maxilla - forms upper jaws
7. Mandible - lower jaws, only moveable bone of the skull

Sutures - connection points between skull bones

1. ___________________________ between frontal and parietal bones
2. ___________________________ between occipital and parietal bones
3. ___________________________ between temporal and parietal bones
4. ___________________________between parietal bones

Fontanels - "soft spots" of an infant's skull, these form sutures as you age, top spot is the anterior fontanel

fontanel

Foramen Magnum - Large opening through the underside of the skull, where the spinal cord enters skull

The Rest of the Bones

Vertebrae - Cervical | Thoracic | Lumbar

Ribs - Thoracic Cage, 12 pairs

_______________ - first seven pairs, attach directly to sternum
_______________ - last five pairs
________________ - last two pairs

Pectoral Girdle: Shoulder. Two clavicles (collar bones) and two scapula (shoulder blade)

Upper arm - humerus.
Lower arm - _______________________ and ____________________
Wrist - 8 small bones called ____________________________
Hand: Metacarpals
Fingers: _______________________

Pelvic Girdle: Hips. Two large bones called _____________________________

Upper leg - ______________________________
Lower leg - _________________ and __________________ (watch your spelling!)
Ankle and Upper foot - 7 bones called _____________________________
Largest is the heel bone called the _________________________________
Foot: _______________________________

Toes: Phalanges

Carpals and Tarsals

carpalstarsal

Broken Bones

Closed | Open (compound) | Multiple | Comminuted | Greenstick | Spiral