bones

Cartilage

A strong, flexible connective tissue that provides support and cushions joints.

articular cartilages

Ends of most bones at movable joints

costal cartilage

Ribs to sternum

Where is cartilage found?

• External ear

• Nose

• Larynx — including epiglottis

• Respiratory tubes

• Between vertebrae — intervertebral discs

• Pubic symphysis

• Certain movable joints — articular discs/menisci

perichondrium

Cartilage is surrounded by a layer of dense irregular connective tissue

Hyaline cartilage 

Looks like frosted glass

It makes up the articular cartilage that covers the ends of adjoining bones in movable joints.

It also forms the cartilaginous attachments of the ribs to the sternum, accounts for most of the cartilage found in the respiratory structures, and forms the embryonic skeleton

Elastic cartilage

similar to hyaline cartilage, but its matrix contains many elastic fibers along with the delicate collagen fibrils

good at bending

Fibrocartilage

an unusual tissue that resists both strong compression and strong tension (pulling) forces

Occurs in certain ligaments and certain cartilages that experience both of these forces.

Locations of Fibrocartilage

 anulus fibrosus portion of the discs between the vertebrae and in the articular discs of some joints, for example the menisci of the knee.

Locations of elastic cartilage

epiglottis and the outer ear are both made from elastic cartilage

Location of hyaline cartilage

Articular surfaces, nose, trachea, larynx, costal cartilage

Function of hyaline cartilage

Support, cushioning, reduces friction

Function of elastic cartilage

Flexible support; maintains shape

Function of Fibrocartilage

Resists compression and absorbs shock

Location of Fibrocartilage

Intervertebral discs, pubic symphysis, menisci of knee

appositional growth

growth from outside,” cartilage-forming cells (chondroblasts) in the surrounding perichondrium produce the new cartilage tissue by actively secreting matrix

interstitial Growth

growth from within,” the chondrocytes within the cartilage divide and secrete new matrix.

Why are bones organs

because they contain several different tissues

Support

Provides the body with structure and shape.

Movement

Bones act as levers that muscles use to move the body.

Protection

Protects vital organs, such as the brain, spinal cord, and heart/lungs.

Mineral storage

Stores calcium and phosphate.

Blood cell formation & energy storage

Red marrow produces blood cells; yellow marrow stores fat.

Energy metabolism

Bone cells release hormones that help regulate blood sugar and energy metabolism.

What are the six major functions of the bony skeleton?

1. Support

2. Movement

3. Protection

4. Mineral storage

5. Blood cell formation & energy storage

6. Energy metabolism

Osteogenic cells 

are stem cells that differentiate into bone-forming osteoblasts.

Osteoblasts

are cells that actively produce and secrete the organic components of the bone matrix

Osteocytes

function to keep the bone matrix healthy.

Osteoclasts

break down bone by secreting hydrochloric acid and lysosomal enzymes.

How do bones withstand tension and compression

Collagen fibers resist tension, while calcium mineral salts resist compression.

Foramen

Opening for nerves and blood vessels

Fissure

Narrow slit for nerves and blood vessels

Meatus

Canal-like passageway

Sinus

Air filled space within a bone

Fossa

Depression that provides space for another structure

Sulcus (groove)

Groove for a nerve, blood vessel, or tendon

Condyle

Rounded surface that forms a joint

Facet

Flat surface that forms a joint

Head

Expanded end that forms a joint

Process

Projection for muscle/ligament attachment

Tubercle

Small projection for muscle/ligament attachment

Tuberosity

Large, rough projection for muscle attachment

Crest

Narrow ridge for muscle/ligament attachment

Spine

Sharp, slender projection for muscle/ligament attachment

Trochanter

Very large projection for muscle attachment

compact bone

dense outer layer that looks smooth and solid to the naked eye

 spongy bone

a honeycomb of small needle-like or flat pieces called trabeculae

Organic compounds of a bone

Collagen fibers → flexibility and tensile strength

Inorganic compounds of a bone

Calcium phosphate/mineral salts → hardness and resistance to compression

Intramembranous ossification:

Bone develops directly from connective tissue; forms most flat bones.

Endochondral ossification

Bone develops by replacing a cartilage model; forms most long bones.

 reduction

 the realignment of the broken bone ends to repair a fracture.

closed reduction

The bone ends are coaxed back into position by the physician’s hands

Comminuted

Bone breaks into 3 or more pieces.

Compression

Bone is crushed, often in vertebrae.

Spherical

Bone breaks into a round/spherical shape.

Epiphyseal

Fracture occurs through the epiphyseal plate.

Depressed

Bone is pushed inward, common in skull fractures.

Greenstick

Bone bends and partially breaks; common in children

List symptoms of osteoporosis.

• Often no symptoms until a fracture occurs

• Bone fractures easily, especially hip, spine, and wrist

• Back pain

• Loss of height

• Stooped/hunched posture

• Bones become weak and fragile

Name two ways aged bone differs from young bone.

• Aged bone: Less dense and more brittle; more likely to fracture.

• Young bone: More dense, strong, and flexible.