The Skeletal System · Osteoclasts are also prominent in the tissue destruction commonly found in...
Transcript of The Skeletal System · Osteoclasts are also prominent in the tissue destruction commonly found in...
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: