bones skeletal system. what happened to all the bones?? as a newborn you are born with over 300...
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WHAT HAPPENED TO ALL THE BONES??
As a newborn you are born with over 300 bones. As an adult you have only 206! What happened to all the other bones?
Newborn baby
CAN YOU BELIEVE WE HAVE 206 BONES?
Skull and upper jaw—21 bones
Ear—3 tiny bones
Lower jaw (mandible)
Front neck bone (hyoid)
Backbone/spine—26 separate bones (vertebrae)
Ribs—12 pairs
Breast bone
Upper limbs—32 bones (2-shoulder, 3 arm, 8 wrist, 19 hand)
Lower limbs—31 bones (1 hip, 4 leg, 7 ankle, 19 foot)
FUNCTIONS OF THE SKELETON
1. Support
2. Protection
3. Movement
4. Storage of minerals
5. Production of blood cells
AXIAL SKELETON
• Consists of the following bones:
• Skull• Vertebral column• Rib Cage
Protects Vital Organs
APPENDICULAR SKELETON
• Arms and leg bones, pelvis, and shoulder areas
• Movement• Production of blood
cells• Storage of minerals
Appendicular
Axial
PARTS OF A BONEA. Periosteum—living membrane
covering bone, except joint
B. Spongy bone—tissue with many spaces, located at end of long bones & in the middle of flat bones
C. Compact bone—very dense, located in shafts of long bones
D. Epiphyseal plate—growth plate
E. Marrow
A. Red—produces RBCs
B. Yellow—mostly fat cells
PARTS OF A BONE
F. Haversian Canals—spaces through which nerves and blood vessels pass
G. Osteoblasts—bone builder cells
H. Osteoclasts—bone destroyer cells
JOINTS
• Joints are the places where bones meet and touch
• There are three classification of joints
• Immovable• Slightly Movable• Freely Movable
TYPES OF FREE MOVING JOINTS
BALL & SOCKET JOINT
HINGE JOINT
A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders.
A hinge joint allows extension and retraction of an appendage.
TYPES OF FREE MOVING JOINTS
PIVOT JOINT
GLIDING JOINT
SADDLE JOINT
saddle joint allows movement back and forth and up and down, bot does not allow for rotation like a ball and socket joint.
gliding or plane joint bones slide past each other. Midcarpal and midtarsal joints are gliding joints
Pivot joints allow rotation around an axis. The neck and forearms have pivot joints. Neck--occipital bone spins over the top of the axis. Forearms--radius and ulna twist around each other.
CARTILAGE1. Some always present
2. Ossification—replacement of cartilage with bone
3. Bursae—fluid-filled sacs that lubricate some freely moving joints
TYPES OF BONES• Long—have a tubular shaft & articular surface at
each end
• Short or Irregular—are variable in size and shape and are generally compact in nature (hand and foot)
• Flat—are thin and have broad surfaces (ribs, sternum, hips, scapula)
DISEASES AND DISORDERS
• Bursitis—is an inflammation of the bursa, causing pain in the body’s joints
• Osteoarthritis--(also called degenerative joint disease) occurs when a joint wears out
DISEASES AND DISORDERS
• Osteoporosis—disease resulting in the loss of bone tissue.
• Scoliosis—a side to side curve of the spine