1. Chapter 10
Skeletal System

2. Outline
Tissues of the Skeletal System
Bone Growth and Repair
Bone Development
Bone Repair
Bones of the Skeleton
Bone Classification
Axial and Appendicular Skeleton
Articulation
Movements Permitted by Joints

3. Tissues of the Skeletal System
Bone.
Compact bone is highly organized and composed of tubular osteons.
Osteocytes lie in lacunae, tiny chambers arranged in concentric circles around a central canal.
Spongy bone contains numerous plates (trabeculae) separated by unequal spaces.
Spaces are often filled with red bone marrow.

4. Tissues of the Skeletal System
Cartilage
Cartilage is flexible because the gel-like matrix contains collagenous and elastic fibers.
Three types differ according to type and arrangement of fibers.
Hyaline - Firm and flexible.
Fibrocartilage - Strong.
Elastic - Flexible.

5. Tissues of the Skeletal System
Fibrous Connective Tissue
Made of rows of fibroblasts separated by bundles of collagenous fibers.
Makes up ligaments (connect bone to bone) and tendons (connect muscles to bones at joints).

7. Bone Growth and Repair
Several different types of cells are involved in bone growth and repair.
Osteoprogenitor cells.
Osteoblasts.
Osteocytes.
Osteoclasts.

8. Bone Development and Growth
Ossification refers to bone formation.
Intramembranous ossification - Bones develop between sheets of fibrous tissue.
Endochondral ossification - Cartilage breaks down in the center of the diaphysis.
After birth, the ends of developing bones continue to grow, but secondary ossification centers soon appear.
Growth plate remains between primary and secondary ossification centers.

9. Endochondral Ossification

10. Remodeling of Bones
Osteoclasts derived from monocytes in red bone marrow break down bone, remove worn cells, and assist in depositing calcium in the blood.
Osteoblasts take calcium from blood and form new bone.

11. Bone Repair
Fracture repair takes place over a span of several months in a series of four steps.
Hematoma.
Fibrocartilaginous callus.
Bony callus.
Remodeling.
Naming of a fracture indicates what kind of break occurred.

12. Bone Fracture and Repair

13. Bones of the Skeleton
Skeletal Functions.
Support body.
Protect soft body parts.
Produce blood cells.
Store minerals and fat.
Permit flexible body movement.

14. Bone Classification
Bones are classified according to their shape, and whether they occur in the axial skeleton or the appendicular skeleton.
Axial - Midline.
Appendicular - Limbs and their girdles.

15. The Axial Skeleton
The axial skeleton lies in the midline of the body and consists of:
Skull.
Hyoid bone.
Vertebral column.
Rib cage.

16. The Skull
The skull is formed by the cranium and the facial bones.
The cranium contain eight bones.
Frontal bone
Two parietal bones.
Occipital bone.
Two temporal bones.
Sphenoid bone.
Ethmoid bone.

17. Bones of the Skull

18. The Facial Bones
The most prominent facial bones are the mandible, maxillae, zygomatic bones, and nasal bones.
Mandible is the movable, lower jaw.
Maxillae form upper jaw.
Zygomatic bones form cheek prominence.
Nasal bones form the bridge of the nose.

19. Bones of the Face

20. Hyoid Bone
The hyoid bone is not part of the skull, but is part of the axial skeleton.
Only bone that does not articulate with another bone.

21. The Vertebral Column
Column made of thirty-three vertebrae.
Spinal cord passes through the vertebral canal and gives off spinal nerves.
Vertebrae named according to location.
Cervical.
Thoracic.
Lumbar.
Sacrum.
Coccyx.

22. The Vertebral Column
Intervertebral disks composed of fibrocartilage are found between the vertebrae and provide padding to absorb shock caused by movements and also provide flexibility of the column.

24. The Rib Cage
The rib cage is composed of the thoracic vertebrae, ribs and associated cartilage, and the sternum.
Twelve pairs of ribs.
All connect to thoracic vertebrae in back.
Upper seven pairs (true ribs) connect to sternum by costal cartilage.
Next three pairs (false ribs) attach to sternum by common cartilage.
Last two pairs (floating ribs)do not attach to sternum.

25. Thoracic Vertebrae and Rib Cage

26. The Appendicular Skeleton
The appendicular skeleton consists of bones within the pectoral and pelvic girdles and their attached limbs.
The pectoral girdle and upper limb (arm) are specialized for flexibility.

27. Bones of Pectoral Girdle and Arm

28. The Appendicular Skeleton
The Pelvic Girdle and Lower Limb.
The pelvis is a basin composed of the pelvic girdle, sacrum, and coccyx.
Pelvis bears the weight of the body, protects organs within the pelvic cavity, and serves as attachment point for the legs.
Femur is the longest and strongest bone in the body.

29. Bones of the Lower Limb

30. Articulations
Bones are joined at joints.
Cartilaginous joints are connected by hyaline cartilage.
Synovial joints separate the bones by a cavity.
Hinge.
Ball-and-socket.

31. Knee Joint

32. Movements Permitted by Synovial Joints
Angular Movements.
Flexion - Decreases joint angle.
Extension - Increases joint angle.
Adduction - Movement towards midline.
Abduction - Movement away from midline.

33. Movements Permitted by Synovial Joints
Circular Movements.
Rotation - Movement around axis.
Supination - Rotation with palm upward.
Circumduction - Movement in wide circle.
Special Movements.
Inversion (sole inward) and eversion (sole outward).
Elevation (lifting up) and depression (moving down).

34. Joint Movements

35. Bone Homeostasis
Rib cage enables oxygen to enter bloodstream.
Red bone marrow produces red and white blood cells.
Jaw and teeth chew food, aiding digestion.
Bones protect internal organs.
Calcium storage.
Efficient locomotion.

36. Lecture Review
Be able to describe the Tissues of the Skeletal System
How do bones Grow and Repair themselves?
Be able to list the major Bones of the Skeleton and How we classify bones.
Be able to determine if the bone is part of the Axial or the Appendicular Skeleton
What is an Articulation?