Chapter 6: Bones and Skeletal

Function of the skeletal system

1. support

2. movement

3. protection of underlying organs

4. mineral storage

5. blood-cell formation

6. energy metabolism

Function and structure of cartiliage

1. Resis compression and tension

2. Cartilage, firm but flexible and cells separated by abundant extracellular matrix (holds 80% water) - no blood vessls or nerves

What cells are found in cartilage?

Chondrocytes

What do chondrocytes do?

maintain cartilage tissue (mature version)

What is the Lacunae?

a cavity where the chondrocyte sits in

What are chondroblasts?

they are immature cartilage cells that are responsible for forming new cartilage. once it finishes building, it becomes a chondrocyte

What is Perichondrium?

irregular C.T. that surrounds cartilage which prevents the bone to overgrow

What are the three types of cartilage?

1. Hyaline cartilage

2. Elastic cartilage

3. Fibrocartilage

What is Hyaline cartilage?

most abundant cartilage; provides support through flexibility

What is Elastic cartilage?

contains many elastic fibers; able to tolerate repeated bending

What is Fibrocartilage?

resists strong compression and strong tension

Where is Hyaline cartilage found?

1. End of long bones

2. ribs

3. nose

4. trachea and larynx

5. growth plates

Where is elastic cartilage found?

1. Ear

2. Epiglottis

Where is fibrocartilage found?

1. intervertebral discs

2. pubic symphysis

3. menisci

What are the four classifications of bones?

1. Long bones

2. short bones

3. flat bones

4. irregular bones

What classification of bone is this?

Long bone

What classification of bone is this?

Flat bone

What classification of bone is this?

Irregular bone

What classification of bone is this?

short bone

What are the four types of cells found in bones?

1. Osteocytes

2. Osteoblasts

3. Osteoclasts

4. Osteoprogenitor

What are Osteocytes?

mature bone cells that maintains the bone

What are Osteoblasts?

synthesize new bone matrix and then when done, becomes osteocytes

What are Osteoclasts?

dissolve bones matrix

What are osteoprogenitor?

stem cell differentiates into osteoblasts

What is Compact bone

a dense outer layer of bone; lots of calcium

What is spongy bone?

internal network of bone

What is Diploe

the spongy bone of a flat bone

What is the chemical composition of bone?

1. 35% organic components

2. 65% inorganic mineral salts

What do organic components consist of?

1. Composed of cells, fibers, and organic substances

2. collagen (abundant)

What do inorganic components consist of?

1. Primarily calcium phosphate

2. resists compression

What are the regulations of bone growth?

1. Growth hormone

2. thyroid hormone

3. sex hormone

Growth hormone

produced by the primary pituitary gland (stimulates epiphyseal plates)

Thyroid hormone

ensures that the skeleton retains proper proportions

sex hormones

Promate bone growth and later induces closure of epiphyseal plates

Where does bone deposit and remove occur

occurs at periosteal and endosteal surfaces

What is bone deposition

accomplished by osteoblasts; working to make new bone tissues and works when the body is active

What is bone reabsorption

accomplished by osteoclasts; gets rid of old bone tissue

What is bone remodeling?

helps maintain constant concentration of Ca2+ and PO43-

What is simple bone fracture?

bone breaks but does not penetrate skin

What is compound bone fracture?

bone breaks and protrudes into the skin

What is closed reduction

no surgery required

what is open reduction

surgery required

What is osteoporosis

• characterized by low bone mass

• Bone reabsorption outpaces bone deposition

• occurs most in women after menopause

What is osteomalacia

• occurs in adults

• bones are inadequately mineralized

What is Rickets

• a type of osteomalacia but occurs in children

• analogues to osteomalacia

• caused by inadequate amount of vitamin D or calcium phosphate in diet

What is Paget’s disease?

characterized by excessive rate of bone deposition and bone absorption

what is osteosarcoma

a form of bone cancer from connective tissue or muscle cell