What is the skeletal system composed of?

-Bones

-Cartilage

-Ligaments

What are the functions of bone?

-Support

-Protection

-Movement

-Hemopoiesis

-Storage of minerals

-Storage of energy reserves

What are long bones? (Be able to describe them and give an example)

-Longer than they are wide

-Most common

-Elongated, cylindrical shaft

Examples: Arms, legs, fingers...

What are short/irregular bones? (Be able to describe them and give an example)

-They are as long as they are wide

Examples: Carpals, tarsals, and sesamoid

What are flat bones? (Be sure to describe then and give an example)

-Flat, thin surfaces that may be slightly curved

-They provide surface are for muscle

Diaphysis

Elongated cylindrical shaft

Epiphysis

-End of the bone

-Proximal and distal

-Covered with articular cartilage (hyaline)

Medullary Cavity

The hollow cylindrical space within the diaphysis

Periosteum

A tough sheath that covers the outer surface of a bone

Outer layer is thick and tough

Inner layer is softer

Endosteum

Incomplete layers of cells that covers all internal surfaces of the bone (within the medullary cavity)

Blood supply

-Highly vascularized

-1 artery and 1 vein enter into the bone through the nutrient foramen

What are the two types of bone tissue?

Compact and Spongy

What is compact bone?

-Dense tissue

-Appears white, smooth, and solid

-Its structural unit is osteon

What are the parts of an osteon?

-Central canal

-Lamellae

-Lacuna

-Osteocyte

-Canaliculi

-Perforating Channels

What is the central canal (Haversian canal)?

-This is the central of the osteon that contains blood vessels and nerves

What is the Lamellae?

Concentric rings of bone matrix surrounding central canl

Circumferential lamellae

These are the rings immediately internal to the periosteum

Interstitial lamellae

These are between osteons that have been partially resorbed

What is lacuna?

Small space between lamellae where osteocytes live

What are osteocytes?

-Mature bone cells

-They help maintain the bone matrix and live in the lacuna

What are canaliculi?

These are small channels that connect the lacuna

What are perforating channels?

-Small channels that run through the lamella

-They contain blood vessels and nerves

What is spongy bone?

Location: Internal to the compact bone

Appearance: Porous

Erythrocytes are produced here

Trabeculae

-Open lattice of narrow rods and plates of bone

-space filled with marrow

Osteogenesis

The process of bone formation

This begins during weeks 8-12 of fetal development and starts off as mesenchyme tissue

Intermembranous ossification

this is the formation or developmental process of flat bones

(steps are in your power points)

Endochondral Ossification

This is the formation or development of long bones

(steps are in your power points)

Types of cells

-osteoprogenitor

-osteoblast

-osteocyte

-osteoclast

osteoprogenitor

stem cells

osteoblasts

immature bone cells

osteocyte

mature bone cells

osteoclast

specialized bone cells

Epiphyseal pate

-Zone 1: zone of resting cartilage

-Zone 2: zone of proliferating cartilage

-Zone 3: zone of hypertrophic cartilage

-Zone 4: zone of calcified cartilage

-Zone 5: zone of ossification

(go to power point for more information)

What are the two ways a facture can occur?

1.) An unusual stress on normal bone

2.) Normal stress on abnormal bone

How are fractures classified?

-Stress

-Pathologic

-Simple

-Compound

Stress

Thin break caused by increased, repetitive physical activity

Pathologic

bone that has been weakened by disease

Simple

does not pierce skin

Compound

pierces the skin

Hormones that increase bone tissue

-Growth hormones

-Thyroid hormones

-Calcitonin

-Sex hormones

Hormones that decrease bone tissue

-Parathyroid hormone

-Serotonin

-Sex hormones

-Glucocorticoids

Growth hormone

-stimulates liver to produce IGF (insulin-like growth factor)

-cause cartilage proliferation at epiphyseal plate

Thyroid hormone

stimulates the metabolic rate of osteoblasts

Calcitonin

promotes calcium deposition and inhibits osteoclasts

Sex Hormones (IBT and DBT)

stimulate osteoblast: promotes epiphyseal plate growth and closure

Parathyroid hormone

-increases blood calcium levels

-increases osteoclast activity

Serotonin

high levels of this hormone inhibits osteoprogenitor cells from differentiating into osteoblasts

Glucocorticoids

high levels increase bone loss