Skeletal System

• protects interal organs
• serves as anchor for muscle attachments
• aids in movement
• stores minerals
• produces blood cells

• cartilage
• ligaments
• tendons
• bones

• long: (arm and leg)
• short: (hands and feet)
• flat: (skull)
• round: (kneecap)
• irregular: other

• mineral salts, calcium, phosphate
• living cells, nerves, and blood vessels

in the interior of bones

• outer hard shell of bone
• composed of osteons

bone cells are found in the lacune

• concentric circles around a central canal
• house osteocytes
• connect to each other by canaliculi

• porous (spongy) found on the inner surface and ends of long bones.
• less dense but still strong becuase of trabeculae

strengthen spongy bone

found in spaces beteween trabeculae

found at the ends of long bone

shaft of the long bone

• inside diaphysis
• filled with yellow bone marrow (fat)

• fibrous connective tissue
• covers bone except at joint surfaces

in utero at 6 weeks old as hyaline cartilage

bone replacing cartilage

• chondroblast die and matrix dissolves making room for blood vessels
• periosteum forms and produces osteoblasts
• osteoblasts + collagen + enzyme that produces hydroxyapatite

cartilage producing cell

bone forming cell

• released by an enzyme that promotes crystalization of calcium phosphate
• traps osteoblast and forms the lacunae

• resting
• proliferating
• degenerating
• ossification

attache epiphyseal plate to bony tissue of epiphysis

produces new chrodroblasts

cartilage cells die

bone formation

in women at age 18 and men around 30

chrondoblasts and osteoblasts for a growth spurt. osteoblasts grow faster to overtake cartilage.

• males
• women have longer torso allowing for better balance

cells that break down bone and minerals are released into the blood

• blood clotting, muscle contraction and nerve function
• when low, osteoclasts break down bone to supply the needed calcium

• releases calcium from bone
• signals kidneys to decrease calcium excretion

• produced by thyroid
• decreases calcium concentration in the blood

• maintain calcium levels
• when high: osteoblasts remove ca from blood and make bone
• when low: osteoclasts break down bone and release ca into blood

stops osteoclast activity

• older women- decline in estrogen- allows osteoclast activity to increase - bone breakdown
• increases bone breakage

a mass of clotted blood cells

206 bones

• trunk of body
• skull
• spine
• ribs
• sternum

• hip
• shoulder
• limbs

protect brain and form face

• form the upper portion of the skull
• protects sight smell hearing and tast sense organs

forehead

extends across floor of cranium and attaches to all other skull bones

near ears

skull back base

form side of cranium

helps form the eye orbit and nasal septum- separates nasal cavity

• two bones that form much of face.
• upper jaw and allows for nasals

lower jaw

cheek bone

air pocket within bones of face

• located at the root of the tounge
• attaches muscles and ligaments is NOT a joint
• anchors tounge and swallowing muscles

• 33 vertebrae
• houses and protects spinal cord

fibrocartilaginous pads that cushion the vertebrae

neck region

upper back

small of the back

bottom of spine

thoracic vertebrae, 12 ribs, and sternum

floating ribs only attached n back

• consists of three fused bones
• ilium
• ischium
• pubis
• contribute to acetabulum

cup shaped socket for the head of the femur to form hip joint

seven bones form the ankle and heel

five bones form the arches

toe bones

• scapula (shoulder blade)
• clavicle (collarbone)

long bone of the arm

long bones of forearm

eight bones to form palm and fingers

opposable which permits the grasping of many items with great percision

• immovable
• found between cranial bones

wide range of motion

knee and elbow

neck

hips and shoulders

decreases joint angle

increaswes joint angle

move toward the midline

movement away from midline

movement of a body part around its own axis

movement of a body part in a wide circle