Chapter 5

Structure

Protection

Red blood cell formation

Movement

Storage: fat in yellow marrow, calcium

(hard matrix), phosphorus

Axial system: skull,

vertebrae, sternum,

sacrum, ribs (p125)

Appendicular

system: all the other

bones and joints

Compact bone:

mostly dense, smooth

bones.

Spongy bone: not

dense, spongy-

looking bone, BUT it

is still hard!

Long bone: • longer than wide,

mostly compact

bone: arm and leg

bones

Short bone: • cube-shaped, mostly

spongy: carpals and

tarsals and patella

Flat bones: • thin, flat, curved, 50/50

comp/spongy: ribs,

skull, sternum and

scapula

Irregular bones: • what’s left over!

Vertebrae, pelvic and

sphenoid bones

P. 118 Diaphysis: shaft of long bone Epiphysis: ends of diaphysis

(proximal/distal) Articular cartilage: hyaline cartilage lining

the joints of the epiphysis. Epiphyseal line: what’s left of the growth

plate (AKA: epiphyseal plate) Periosteum: bone “skin”, lines the outside Endosteum: lines the medullary cavity

Small to Big

Osteocyte: (“osteo”- bone, “cyte”- cell)

mature bone cell.

Lacunae: hollow area in hard bone matrix

that houses the osteocyte

Lamellae: rings of lacunae

Osteon (Haversian System): system of

lamellae that make up the majority of

compact bone

Blood Canals

Vertical canals = Haversian canal

Horizontal canals = Volkmann’s canal

Capillary canals (surround osteocytes) =

canaliculi

Ossification: bone formation (during fetal

development)

*Remember, fetal skeletons start as

cartilage.

1. hyaline cartilage is covered with bone

formed from cells called osteoblasts.

2. the center of the hyaline cartilage is

“eaten” away forming the medullary

cavity

Length: epiphyseal plate & articular

cartilage grow new cartilage away from

the medullary cavity and new bone

towards the cavity via osteoblasts.

Width: osteoblasts in periosteum add

new bone and osteoclasts (bone eating

cells) in endosteum digest cells near the

marrow

Control: Growth pre-puberty is controlled by

growth and sex hormones. Bone constantly changes via osteoblasts

and osteoclasts • Calcium levels in blood (blood steals from bones

if it has to!)

• Pull of gravity on bones

• Pull of muscles on bones (remember Walle?)

• Stress areas or breaks

Types of fractures (p. 123)

1. simple fracture: the bone does not

protrude from the skin

2. compound fracture: the bone does

protrude from the skin

Treatments:

Closed reduction: put back together

without surgery.

Open reduction: put back together via

surgery, pins, wires, screws, bolts, ect…

The major events of bone repair:

1. hematoma: blood-filled swelling

2. fibrocartilage callus: massive repair

tissue site (cartilage, bone, collagen)

3. bony callus: osteoblasts and

osteoclasts migrate here and replace

fibrocartilage.

4. bony callus remodeling

Articulations: points of connections

between bones (no joint for the hyoid

bone in neck)

Classifications: 1. by function (amount of

motion) & 2. by structure

Functional classes: • Synarthosis: immovable

• Amphiarthrosis: slightly movable

• Diarthrosis: movable

Structural classes (page 148) 1. Fibrous joints: mainly immovable

(synarthrosis) joints connected tightly by fibrous tissue • Examples: sutures of the skull & syndesmoses of the

distal fibula and tibia

2. Cartilaginous joints: mainly semi-movable (amphiarthrosis) joints connected by cartilaginous tissue. • Examples: pubic symphysis, intervertebral joints,

epiphyseal plate & rib/sternum joints

Structural classes (page 148) 3. Synovial joints: mainly moveable

(diarthrosis) joints, separated by synovial fluid.

Four distinguishing features: A. articular cartilage on articulating bones B. fibrous articular capsule lined by synovial

membranes C. joint cavity containing synovial fluid D. reinforcing ligaments that surround and

support the capsule Examples: shoulder and hip joints, bursae and tendon

sheaths

Types of synovial joints 1. Plane joint: flat articulations, carpals 2. Hinge joint: cylinder/trough articulations,

elbow 3. Pivot joint: round/ring articulations,

proximal radioulnar joint 4. Condyloid joint: oval articulations, knucks 5. Saddle joint: concave/convex articulations,

proximal thumb joint 6. Ball & socket joint: well…, shoulder & hip

Inflammatory Disorders of Joints 1. Bursitis, sprains 2. Acute arthritis: usually a bacterial infection

like lyme disease 3. Chronic arthritis:

a. Osteoarthritis: most common form especially in elderly; caused from years of wear and tear

b. Rheumatoid arthritis: autoimmune disease, white blood cells produce a joint eating tissue that ossifies and fuses diarthotic joints

c. Gouty arthritis: accumulation of spiky uric acid crystals in joints (often the large toe)