SKELETAL SYSTEMAnimal Physiology :

• Support- framework that supports body

and cradles its soft organs

• Protection- for delicate organs, heart,

lungs, brain

• Movement- bones act as levers for muscles

• Mineral storage- calcium & phosphate

• Blood cell formation- hematopoiesis

• Long Bones- metacarples, metatarsals, phelangies, humerus, ulna, radius, tibia, fibula

• Short Bones- carpals, tarsals

• Flat Bones- rib, scapula, skull, sternum

• Irregular Bones- vertebrae, some facial bones

• Sesamoid- patella

Quick Facts• Do we have more bones when we are a baby or when we are all grown up?

Baby has 305 bones and an adult has 206 bones. This is because as we grown some

of our bones join together to form one bone.

• The longest bone in our bodies is the femur (thigh bone).

• The smallest bone is the stirrup bone inside the ear.

• Each hand has 26 bones in it.

• our nose and ears are not made of bone; they are made of cartilage, a flexible

substance that is not as hard as bone.

Differences between males and females: Males and females have slightly different

skeletons, including a different elbow angle. Males have slightly thicker and longer legs

and arms; females have a wider pelvis and a larger space within the pelvis, through

which babies travel when they are born.

Distal

epiphysis

Proximal

epiphysis

diaphysis

yellow marrow

epiphyseal line

periosteum

compact bone

spongy bone

Endosteum

hyaline cartilage

Sharpey’s fibers

Axial and Apendicular Skeleton

Posterior View

• Warm and moisten air

• Lighten the skull

• Enhance voice resonance

Frontal Sinus

Ethmoid Sinus

Sphenoid Sinus

Maxillary Sinus

Cervical Vertebrae(7)

Thoracic Vertebrae(12)

Lumbar Vertberae (5)SacrumCoccyx

The Vertebral Column

Cervical Vertebrae

Sternum

True Ribs (7)

False Ribs (3)

Floating Ribs (2)

The Thoracic Cage

Sacrum & Coccyx

Bones of the Pectoral Girdle (Gelang Bahu)

Humerus

Ulna

Radius

8 Carpals

14 Phalanges

5 Metacarpals

Pelvis

Ischium

Ilium

Acetabulum

Pubis

Ischium

Obturator

foramen

Pelvis (lateral view)

Male Pelvic Girdle Female Pelvic Girdle

Patella

The Lower Limb (Legs)

Femur

Tibia

Fibula

5 Metatarsals

14 Phalanges

7 Tarsals

metatarsals

phelangies

tarsals

metatarsals

phelangies

tarsals

Immovable Joints

(synarthrosis)

suture

pubis symphisis

Slightly Movable Joint

(amphiarthrosis)

femur

ligaments

pelvis

(diarthrosis)- freely moveable

femur

pelvis

hyaline cartilage synovial

cavity

joint capsule

Abduction

Extension

RotationFlexion

Adduction

Synovial Joint Movement

275 bones12 weeks (6-9 inches

long)

cartilagecalcified

cartilage

bone

epiphyseal

plate

epiphyseal

line

Endochondral Ossification

2o ossification

center

Fetus: 1st

2 months

AdultChildhood

Just before

birth

Osteoblast

Osteocyte

Osteoclast Eats bone (Bone resorption)

Builds new bone

Mature bone cell

Bone resorption is the process by which osteoclasts break down bone[1] and

release the minerals, resulting in a transfer of calcium from bone fluid to the

blood.

The osteoclasts are multi-nucleated cells that contain numerous mitochondria

and lysosomes. These are the cells responsible for the resorption of bone.

Osteoclasts are generally present on the outer layer of bone, just beneath the

periosteum. Attachment of the osteoclast to the osteon begins the process. The

osteoclast then induces an infolding of its cell membrane and secretes

collagenase and other enzymes important in the resorption process. High levels

of calcium, magnesium, phosphate and products of collagen will be released into

the extracellular fluid as the osteoclasts tunnel into the mineralized bone.

Osteoclasts are also prominent in the tissue destruction commonly found in

psoriatic arthritis and other rheumatology related disorders.

Bone resorption can also be the result of disuse and the lack of stimulus for

bone maintenance. Astronauts, for instance will undergo a certain amount of

bone resorption due to the lack of gravity, providing the proper stimulus for bone

maintenance.

During childhood, bone formation exceeds resorption, but as the aging process

occurs, resorption exceeds formation.

Bone Repair:1. Electrical stimulation of the fracture site:

• Increases speed and completeness of healing

• The e- stimulation inhibits PTH and slow osteoclasts

down from reabsorbing bone

2. Ultrasound treatment:

• Daily treatments reduce healing time of broken bones

by 25-35%

3. Free vascular fibular graft technique:

• Transplant fibula in arm

• Gives good blood supply not available in other

treatments

4. Bone substitutes:

• Crushed bone from cadaver- but risk of HIV and

hepatitis

• Sea bone- coral

• Artificial bone- ceramic

hematomacallus bony callus

bone

remodeling

Diseases of the Skeletal System:

Osteoporosis- bone reabsorption

outpaces bone deposit; bones

become lighter and fracture easier

Factors:

• age, gender (more in women)

• estrogen and testosterone decrease

• insufficient exercise (or too much)

• diet poor in Ca++ and protein

• abnormal vitamin D receptors

• smoking

Osteoporosis

29 40 84 92

Rickets- vitamin D deficiency

Osteomalacia- soft bones, inadequate

mineralization in bones, lack of vitamin D

Pagets Disease- spotty weakening in the

bones, excessive and abnormal bone

remodeling

Rheumatoid arthritis- autoimmune

reaction

Diseases of the Skeletal System: