Osteology

Osteology

Study of bones

Functions of the skeletal system

1. Foundations & skeletal support

2. Mobility

3. Organ protection

4. store calcium ions

Tissues of skeletal system

1. Bone CT

2. Adipose CT

3. Hyaline cartilage CT

4. Fibrocartilage CT

5. Dense Regular CT

Bone CT in the skeletal system…

is majority of tissue making up all bones

Adipose CT in the skeletal system

forms cushions in high impact joints & found in the center of hollow long bones in adults

Hyaline Cartilage CT in the skeletal system..

forms smooth, low friction surface at the ends of bones

Fibrocartilage CT in the skeletal system…

absorbs shock

Dense Regular CT in the skeletal system..

Forms tendons & ligaments

Bone cells are surrounded by a rigid ground substance made up of

1. Calcium phosphate

2. Collagen protein fibers

Bone Tissue

1. Compact

2. Spongy

Compact Bone Tissue

Function - External bone covering of all bones

Location - long bones

Spongy Bone Tissue

Function - absorbs pressure from diff directions & stores bone marrow

Location - Epiphyses of long bones & center of flat, irregular, & short bones

Bone shapes

1. Long bones

2. Short bones

3. Flat bones

4. Irregular bones

Epiphysis

rounded proximal and distal ends of a long bone

Function - attachment point for ligaments & tendons

Diaphysis

long, cylindrical shaft

Function - resist bending & twisting

Epiphyseal line

Remnant of growth plate

Function - indicates bone has stopped growing

Articular cartilage

CT that covers ends of bones

Function - smooth joint movement & shock absorption

Medullary cavity

hollow space in diaphysis

Function - holds red & yellow bone marrow

Red bone marrow

Function - produces blood cells

Yellow bone marrow

fat cells store energy

Function - stores fat for E

Periosteum

tough fibrous membrane made up of fibrous layer & osteogenic layer

Function - attachment for muscles & tendons

Fibrous layer

Outer layer of fibroblasts & cambium layer

Function - structure integrity & bone growth/healing

Osteogenic layer

Inner cellular layer

Function - bone growth, repair, remodeling

Endosteum

Thin cellular membrane lining inner cavities/spaces of long bones

Function - bone growth, repair, remodeling

Types of bone cells

1. osteocytes

2. osteoprogenitor cells

3. osteoblasts

4. osteoclasts

Osteocytes

Typical bone cell that monitor & maintain bone matrix

Function - Regular bone remodeling, calcium phosphate metabolism, & response to mechanical stress

Osteoprogenitor cells

Stem cells that develop into bone (osteoblasts & osteocytes)

Function - bone formation, remodeling, differentiation

Osteoblasts

Bone makers

Function - secrete collagen & calcium phosphate to form new bone

Osteoclasts

Bone breakers for resorption & remodeling

Function - Dissolve & break down old/damaged bone cells to create new bone tissue

Bones are highly

innervated

Osteons

Single column of compact bone

Concentric lamellae

Sheets of bone tissue rolled up & stacked inside each other

Osteocytes

Typical bone cell

Function - Maintain bone matrix

Canaliculi

“Little canal”

Narrow grooves in bone tissue that connect adjacent lacunae

Central Canal

Narrow space running down center of each osteon

Function - allow passage of arteries, veins, nerves

Perforating canals

connect adjacent osteons

Circumferential lamellae

large sheets of lamelle that cover edge of bone tissue

(attached to periosteum)

Interstitial lamellae

sections of bone tissue between osteons

endochondral growth

process of long bones forming from cartilage through ossification

Appositional growth

Process of bone growth from baby bones to adult bones with the use of osteoblasts and osteoclasts

Bone fraction heals by

1. forming hematoma to reduce blood loss

2. forms fibrocartilaginous callus

3. replace cartilage with spongy bone

4. Convert spongy bone to compact one with osteoblasts & osteoclasts

Effects of exercise on bone tissue

impact pressure on bone increases osteoblast activity

osteoporosis

• loss of bone tissue

• decreased osteoblast activity

Osteomyelitis

• infection in bone tissue

• loss of bone tissue due to pathogen

rickets (osteomalacia)

bones are weaker due to less calcium phosphate matrix

Dwarfism

reduction in bone growth (disproportionate & proportionate)