1. The Human skeleton

2. Learning goals
I will identify the main structures and functions of the human skeletal system.

3. Skeletal system 206 bones; about 305 at birth
begin as cartilage and ossify (become harder) as the child gets older

4. 5 Functions
Support - A stiff structure for soft tissues like muscles and organs
Protection - Helps prevent soft tissue injury
Blood Production - Bone marrow produces blood cells
Mineral Storage - Required minerals such as calcium and phosphorus are kept in bone for later use
Movement - Bones provide the leverage for muscles to produce movement

5. Bone composition Bone material includes:
Collagen is a series of rope-like fibers that provide a base network.
This gives bone its flexibility.
Apatite is a collection of minerals (mainly phosphorus and calcium) that covers the collagen.
This gives bone its strength.

6. gives bone its flexibility give bone its strength Bone composition
calcium carbonate + calcium phosphate + collagen (a protein) + water = bone
give bone
its strength
Thus, bone is the
perfect balance between
strength & flexibility
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7. Bone remodelling Bones can repair themselves.
Periosteum is a connective tissue that covers bone and contains two important cells that continuously repair and upgrade bone.
Osteoblasts are cells that lay down new bone material where damage or weakness occurs.

8. Bone remodelling
Osteoclasts are cells that break down bone material for the purposes of proper shaping or mineral needs.
These cells work together when a fracture occurs, whenever bone is weakened, or when minerals are needed.

9. Types of bone: Long
Long Bones - Bones whose length significantly exceed their diameter (ie. femur, humerus).
contain both spongy and compact bone.

10. Types of bone: short
Short Bones - Bones that are small and often square in shape (ie. carpals, tarsals).
consist mainly of spongy bone and are often "load-bearing" bones.

11. Types of bone: flat
Flat Bones - Bones that are thin, wide and often in areas protecting vital organs (ie. skull, ribcage).
also produce more blood cells than other bone types.

12. Types of bone: irregular
Irregular Bones - Bones that have odd shapes or patterns (ie. vertebrae or sacrum).

13. Types of bones: sesamoid
Sesamoid Bones - Bones that are small and wrapped in tendon material (ie. patella).

14. Anatomy of a long bone
There are a few main features of a long bone that are important to know.
See figure 5.4 on pg.127 of text for a diagram of the location of these features.

15. Anatomy of a long bone
Cartilage: referred to as articulating cartilage as it protects the points of articulation (where two bones meet).
allows for smoother movement at joints.
Periosteum: Thin layer of connective tissue that covers bone.
Contains cells for bone re-modelling and is the connecting point for tendons and ligaments.

16. Anatomy of a long bone
Medullary Cavity: Hollow part of bone shaft where bone marrow produces blood cells.
Compact Bone: Dense, rigid bone usually on bone shaft (diaphysis)

17. Anatomy of a long bone
Spongy Bone: Compressive, flexible bone usually on bone ends (epiphysis).
The trabeculae running throughout gives the bone its load-bearing capability and 'spongy' look.
Epiphyseal Plates: Site where most bone growth occurs.
Contains a higher concentration of osteoblasts.
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18. Anatomy of a long bone

20. Bone landmarks Bones often have prominent features called landmarks.
may be ridges, grooves, depressions, or other surface markers on a bone.
can be a point of attachment or allow space for other systems.

21. Skeletal system 80 belong to AXIAL skeleton (head, spine & trunk)
provides structural support for soft tissues
provides protection to vital body organs
126 belong to APPENDICULAR skeleton (shoulder, hip, arms, legs)
responsible for most of body’s movements (provide sites for muscle attachment)
contain marrow (where RBC’s & platelets are formed)
acts as a reservoir for Ca and P (released if nec.)

22. Learning goals
I will identify the main structures and functions of the human skeletal system.

23. Your turn Study your bone diagrams!!!
Read p and make brief notes on injuries and disease