1. Introduction to the Skeletal System

2. Objectives
Be able to list the general functions of the skeletal system
Identify the parts of the skeletal system
Discuss the active tissues found in bone
Classify bones according to shape

3. Human Skeleton Facts Makes up 1/5 of a healthy body’s weight
Adults have 206 bones on average
We are born with 270 bones, but many of fuse together as we grow
Longest bone in the body is the femur
Smallest bone in the body is the stapes bone in the middle ear

4. Divisions of the Human Skeleton
Axial Skeleton: includes the bones of the skull, ribs, spine, and sternum
Appendicular Skeleton: includes the bones of the arms, legs, scapula, clavicle, and pelvis

5. Axial vs. Appendicular

6. Functions of the skeletal System
Support: gives shape & structure to the body
Movement: provides a rigid framework against which muscles can pull
Protection: protects delicate internal organs such as the rib cage protecting the heart & lungs

7. Functions of the skeletal System
Blood Cell Production: site of hematopoiesis, which is the process that produces red blood cells, platelets and some white blood cells from the bone marrow
Storage: stores minerals such as calcium & phosphorus
Endocrine Regulation: bone cells release the hormone osteocalcin which controls the regulation of blood sugar and fat deposition

8. Tissues of the Skeletal System
Bone
Cartilage
Dense connective tissue
Blood
nervous

9. 4 Classifications of Bones
Long bones: have long longitudinal axes and expanded ends
Examples: radius, ulna, femur
Short bones: are cube-like, with roughly equal lengths and widths
Examples: carpals and tarsals
Sesamoid (round) bone: is a special type of short bone that is small and nodular and embedded in a tendon adjacent to a joint
Example: patella (knee cap)

10. 4 Classifications of Bones
Flat bones: are plate-like structures with broad surfaces
Examples: ribs, scapula, and parts of the skull
Irregular bones: have a variety of shapes and most are connected to several other bones
Examples: vertebrae and many facial bones

13. Parts of the Skull

14. Parts of the Skull

15. Differences b/w Males & Females
Males have slightly thicker and longer legs and arms
Males have longer and thicker phalanges
Females have a wider pelvis and a larger space within the pelvis
Females have narrower rib cages, smaller teeth, less angular mandibles, less pronounced cranial features, and carrying angle of the forearm is more pronounced