1. Unit 4 Notes:
Skeletal Function,
Joints & Bone Types

2. (1) Skeletal Parts
Bones
Joints
Cartilage
Marrow

3. (2) Skeletal Function Support Protection Movement
Framework for posture
Limbs act as pillars
Rib cage supports thoracic wall
Protection
Ribs protect lungs and heart
Skull protects brain
Vertebrae protect spinal cord
Movement
Attachment sites for muscles and tendons
Muscles use bones as levers
Joints between allow for range of motion

4. …Function Cont’d… 4. Mineral & Growth Factor Storage
Reservoir for calcium and phosphate
Releases minerals into blood
Growth factors (insulin, transforming factor, morphogenic proteins) in bone
5. Blood Cell Formation
Marrow within cavities of bones (primarily long)
Marrow initiates hematopoeisis (blood cell formation)

5. Diagram Time!

13. (3) How are bones hinged together?
Joints: Connection between two bones.
Filled with cartilage (padding)
Allow for wider range of movement.
Circular
Angular
Reduce rigidity of bone structure.
*Cartilage within joints (in between bones) provides shock absorption, and decreases friction.

14. (4) Injuring Joints Sprains: Dislocations:
Ligaments reinforcing a joint are stretched or torn
If torn badly, can be replaced with muscle
Usually result from inflexibility or irregular movement
Dislocations:
Bones are forced out of alignment
Usually result from serious falls and contact sports
Results in stretching of joint ligaments, leading to future dislocations

15. (5) What are the Bone Regions?
Axial
Down the center of body
Skull, vertebral column, rib cage, center pelvis
Appendicular
Off the sides of body
Upper and lower limbs, shoulder and hip bones

17. (6) What are the types of Bones?
Long
Short
Flat
Irregular

19. (7) Long Bones Longer than they are wide Has a shaft and 2 ends
Weight bearing bones (like steel beams)
Provide the greatest structure and support
Examples:
All limb bones
Except…. Kneecap, Wrist and Ankle bones

21. (8) Short Bones Cube Shaped Allow for wider range of movement
Examples:
Wrist
Ankle

23. (9) Flat Bones Thin, flat and curved
Protect soft tissue (like plates of armor)
Examples:
Sternum
Shoulder blades
Ribs
Skull bones

25. (10) Irregular Bones Complicated, unusual shapes
Muscles, tendons, ligaments usually attach to these
Examples:
Vertebrae
Hip bones

27. (11) Bone Structure Unique based on location + bone type.
Compact Bone (Outer Layer):
Dense
Smooth and Solid to naked eye
Spongy Bone (Inner Layer):
Hole-y (like a honeycomb)
Made of small needle-like, flat pieces called “trabeculae”
Open spaces between trabeculae are filled with red or yellow bone marrow

30. (12) Structure of a Long Bone
Diaphysis:
Center, main shaft
Long part of bone
Made of very thick compact bone surrounding a central marrow cavity
Epiphysis:
Ends of bone
Wider than diaphysis
Made of compact bone which surrounds spongy bone.
Joint surface of each epiphysis is covered with hyaline cartilage

31. Epiphyseal Line: Membranes: Remnant of Epiphyseal Plate
Found in adult bones
Shows amount of cartilage growth during adolescence
Membranes:
Periosteum = Around the outside
Richly supplied with nerve fibers, lymphatic vessels and blood vessels
Provides anchoring points for tendons and ligaments
Endosteum = Around the inside
Surrounds the spongy bone

33. (13) Chemical Composition of Bone
Contains organic & inorganic components
Organic:
Cells (osteoblasts, osteocytes, osteoclasts)
Osteoid
Made of glycoproteins and collagen fibers
Secreted by osteoblasts
“filler matrix” around cells
Contribute to flexibility and tensile strength
Inorganic:
Mineral Salts (calcium phosphates)
Contribute to hardness of bone (allowing for compression resistance)