1. Chapter 7
The Skeletal System

2. Functions of Bone
SUPPORT -
PROTECTION
LEVERAGE
STORAGE
HEMATOPOIESIS

3. Funny Bone Facts
Bone is the 2nd hardest substance in the body, after ___________
Capable of ________-__________ if aligned and kept still!
________________________ = mineralization or hardening of bone
Osteoblasts become trapped in their _______________ due to the bone that they have made
Remember, when they are done making bone, their name changes
Osteocytes communicate with each other via channels called ____________________

4. Bone Structure Two main types of bone:
_________________________- Light and spongy inner layer of bone.
Consists of tiny spicules with bone marrow between them.
Helps reduce the weight of bone; spicules are arranged to withstand the forces that bone is subjected to
_________________________- Heavy and dense outer layer of all bones
Composed of Haversian Systems

5. Haversian Systems
Concentric layers of bone arranged around a central ___________________ _________________.
___________________ _____________- tiny channels in the bone matrix that vessels pass through. They are horizontal, whereas Haversion canals are vertical. 5

6. Bone Structure 3 types of bone cells:
________________________- cells that secrete the matrix of bone
________________________- inactive cells that have become trapped in the matrix they have created
________________________- cells that remodel bone by eating it away from places it is not needed. They allow the body to utilize the calcium that was stored in bone.

7. _________________________- fibrous membrane that covers the outside of bone (except at the joint)
_________________________- fibrous membrane that lines the hollow interior surface of bones.
____________________ - the shaft of long bones
____________________ - the ends of long bones
Bone Structure

8. Bone Formation Bone is formed in 2 ways:
__________________________ (cartilage bone formation)
Grows into and replaces cartilage
How most bones develop
__________________________ (membrane bone formation)
Develops from fibrous tissue membranes
Bone formation and growth is stimulated by GROWTH HORMONE from the _________________ gland in the brain.

9. Endochondral Bone Formation
Cartilage to bone formation
cartilage template is replaced by bone
Starts in the __________________ growth center
Cartilage rods in the ___________________ (shaft) of long bones are gradually replaced by bone.
__________________ growth centers develop in ________________ (ends) of bones
Endochondral Bone Formation

10. Growth plates (epiphyseal plates)
At the time of birth, cartilage remains at each end of long bones between __________________ and __________________.
Sites of creation of new bone that allows bone to lengthen as animal grows.
______________________ is created on epiphyseal side while _______________ is created on diaphyseal side.
Growth plates (epiphyseal plates)

11. Growth plates (epiphyseal plates)
When bone reaches full length, all cartilage is replaced by bone and plates “close”.
Remodeling may take place but bone will not get any longer.
Young animals may have epiphyseal ______________ because this area is weaker than rest of bone.

12. Intramembranous Bone Formation
Occurs only in _______ _________ bones
Bone forms in the fibrous tissue that covers the brain of the ______________.
There is no cartilage intermediary.

13. Bone Shapes
Long Bones
Short Bones
Flat Bones
Irregular Bones

14. Long Bones Longer than they are wide.
There is a proximal epiphysis and distal epiphysis with the diaphysis in between.
EXAMPLES: __________________________________________________________

15. Short Bones Shaped like cubes.
Have a core of cancellous bone covered by compact bone.
EXAMPLES: _____________________________

16. Flat Bones Thin and flat bones
Consists of two layers of compact bone separated by cancellous bone.
EXAMPLES: __________________________________________

17. Irregular Bones
Miscellaneous bones that do not fit into another category.
May have characteristics of more than one category.
EXAMPLES:
___________________________
_____________ - is largest sesamoid bone in body.

18. Bone Marrow
Fills the spaces within center of long bones & within cancellous bone
_______________ bone marrow
________________________- the process of forming new blood cells.
Majority of bone marrow in young animals
__________________ bone marrow
Consists primarily of __________________ connective tissue.
Majority of bone marrow in adult animals
Does not produce blood cells but can revert to red marrow if needed.