Bones Lab True bone is living tissue Composed of living cells – osteocytes Within a mineralized matrix osteocytes

Osteocytes are fed by blood capillaries Bone matrix (with osteocytes) Bone marrow Bone capillaries

Functions of bones 1) Support Large animals need internal structure Without, body cavity would collapse

Land animals needed rigid limbs To hold body up against gravity

2) Lever system for muscle attachment Vertebrates have antagonistic muscle pairs Muscles have pulling strength only No pushing strength Takes a pair of muscles to move body parts E.g., Biceps and triceps move lower arm

E.g. ribs protect lungs and heart 3) Protect vital organs E.g. ribs protect lungs and heart Vertebrae protect spinal cord vertebral foramen

4) Create red and white blood cells Occurs in red bone marrow Porous areas of arm, leg, & rib bones “spongy” bone red morrow yellow marrow (fat storage)

Skeletal anatomy Axial skeleton Skull, vertebrae & ribs Regions: Skull Cervical Thoracic Lumbar Sacral Caudal Appendicular skeleton Limb girdles: Pelvic girdle Pectoral girdle Hind limb Forelimb

Bone terminology Process: outgrowth or projection Foramen: opening or passageway Facet: smooth articulating surface Trochlea: V-shaped articulating surface Fossa: pit or cavity

Thoracic processes

Disarticulated vs. articulated disarticulated human skeleton

Ball and socket joints Shoulder joint Hip joint

Fusing Sacrum

Enjoy! pectoral girdle Os Coxa sacrum Talus