Bones

Anatomy + Physiology

Osteoblast

Produce ECM/Deposit bone

Osteoclast

Dissolve + Break down damaged bone cells

Osteocyte

once osteoblasts, surrounded by lacunae —> osteocyte

Bone Deposition

Process new bone tissue is formed

Bone Reabsorption

Process osteoclasts remove bone, it is reabsorbed by the body

Lacunae

the small cavity containing an osteocyte in bone, or a chondrocyte in cartilage

Canaliculi

ultra small canals radiating from the lacunae

Ligament

short band of tough, flexible fibrous connective tissue which connects two bones or cartilages or holds together a joint.

Tendon

a fibrous connective tissue that attaches muscle to bone

Spongy/Cancellous Bone

lighter and less dense than compact bone - inside of compact bone

Compact/Cortical Bone

The hard, dense outer layer of bones

What is this?

An Osteon

What is the structures highlighted in red?

Osteoblasts (deposit bone)

What is the structures highlighted in orange?

Osteoclasts (break down damaged bone cells)

What is the structures highlighted in yellow?

Lacuna (contain the green)

What is the structure highlighted in green?

Osteocyte (monitor changes in pressure)

What is the structures highlighted in blue?

Lamellae (thin layer, membrane, or plate of tissue - circles central cannal)

What is the structures highlighted in purple?

Canaliculus (Small ducts)

The extracellular matrix of bone is 1/3 ___ and 2/3 ___

Organic, Anorganic

Some of the organic components of bone are…

collagen + glycoproteins + proteoglycans + glycosaminoglycans

Some of the Anorganic components of bone are…

85% Hydroxyapatite and 10% Calcium Carbonate

Axial

Trunk + Skull of skeleton

Appendicular

Arms + Legs + Hips + Clavicle + Scapula

Articulation

Location where two bones meet/join

Long Bone: What is letter A?

Red marrow inside of spongy bone - produces blood cells (hematopoiesis)

Long Bone: What is letter B?

Yellow marrow - stores fat

Long Bone: What is letter C?

Articular Cartilage - lines boney surfaces of joints

Long Bone: What is letter D?

Periosteum - dense layer of connective tissue covering bones (joints not included)

Long Bone: What is letter E?

Endosteum - A membrane lining the inner surface of the bony wall

Long Bone: What is letter F?

Epiphysis - Rounded ends of a long bone

Long Bone: What is letter G?

Diaphysis - The shaft of the bone

Long Bone: What is letter H?

Epiphyseal Plate/Line - Area of cartilage between the end and shaft of bone - allows bone to grow in length

What is this process of bone development?

Endochondral Ossification

What is happening in stage 1? What is the dark orange?

The hyaline cartilage model is surrounded by perichondrium

What is happening in stage 2? What is the red? What is the blue?

Formation of the bone collar around the diaphysis, chondrocytes die, and a cavity is formed for the primary ossification center

What is happening in stage 3? What is the green? What is the red now?

Osteoclasts create primary marrow cavity (red bone marrow), osteoblasts create spongy bone, secondary ossification center forms at epiphysis

What does the purple arrow signify? What is happening in stage 4? What is the pink/magenta?

The arrow signifies the owner of the bones being born. The secondary marrow cavity forms, the secondary ossification center is now at the second epihysis

What is happening in stage 5? What is the orange?

Epiphysis fill with spongy bone, articular cartilage/growth plate forms: allows lengthening of bone

What is happening in stage 6? What is the yellow?

The plate fuses, leaves an epiphyseal line left behind, no more growth

Endochondral Ossification applies to:

all bones below base of skull except calvicles

What is Intramembranous ossification and where does it apply to?

Intramembranous ossification directly converts the mesenchymal tissue to bone, applies to clavicle + most cranial bones

What is happening in stage 1? What time period is this in the healing process?

Hematoma - Inflammation stage - 6-8 hours after the break

What is happening in stage 2? What is the yellow? What time period is this in the healing process?

Soft Callus repair, the yellow is fibrocartilage, 4-6 weeks after break

What is happening in stage 3? What is the green? What time period is this in the healing process?

Hard callus repair, the green is now bone, 6-8 weeks after break

What is happening in stage 4? What time period is this in the healing process?

Remodeling, ~6 months after break