1. The Skeletal System - HBS

2. Functions _________________ Bones are the body’s supporting framework.
Your bones give you shape and structure
Your bones have to support the tissue that you have on your body.

3. Protection
Bones protect our delicate _____________ including the brain, heart, and lungs.

4. Movement Bones need muscles for ________ ___ _____________.
Muscles contract and relax to cause movement of the body.

5. Storage Bones store ____________________
Calcium is needed for nerve impulses to cause muscle movement.

6. The last function….. Hematopoiesis
The process of ____________________ within the bone.

7. Number of Bones
We have 350 bones at birth
Why?
Adults have 206

8. Types of Bones ________
We have four different types of bones found throughout the body
________

9. Long
Short
Flat
Irregular

10. Divisions of the Skeletal System
Axial Skeleton Vs Appendicular – color your picture

12. Bone Is a Living Tissue
Bones need a blood supply, nutrients, and __________
There are also nerves that run through bones as well.

13. Microscopic Structures of Bone
Bone can be divided into how it is constructed
________________________
Both types are found throughout the body and have very specific functions

14. Spongy Bone
Compact Bone

15. Spongy Bone Contains many spaces that may be filled with bone marrow.
The areas of spongy bone can be found at the ________________.
These areas are where hematopoiesis occurs.

16. Compact (dense) Bone Does not contain a network of open spaces.
It is used for ________, structure and support
Yet it is still light so that we can move our bodies without extra weight

17. Structures of Long Bones
Long bones include
Humerus
Ulna
Radius
Femur
Tibia
Fibula

18. Diaphysis The ______________ of the bones.
It is _____________ but made of hard, compact bone.
It is strong in structure
Gives bone their “strength”

19. Epiphyses The _________________ of the bones
Composed of spongy bone and red bone marrow.

20. Medullary Cavity The ________ ________within the bone
Contains yellow bone marrow
Soft and fatty form of bone marrow.

21. Articular Cartilage A thin layer of cartilage covering each epiphysis.
Functions as a _________________________________.

22. Periosteum and Endosteum
__________________- a fibrous membrane covering the long bone except at the joint surfaces.
_________________- a thin membrane that lines the medullary cavity.

23. Compact (dense) Bone Does not contain a network of open spaces.
Bone tissue is composed of repeating, circular units called ___________________.
These circular systems are called _______ as well.
Within each Haversian system, there is a central canal where blood vessels and nerves can be found.

24. The osteon or Haversian systems is composed of layers of a calcified matrix of circles called __________.

25. The darkly-stained spots are spaces called ___________.
The lacunae contain _____________ which are bone cells.

26. ____________________ connect multiple lacunae for nutrients to pass.

27. Nutrients pass from blood vessel in ________________ canal through the canaliculi to the osteocytes.

28. Osteoblasts Bone ____________ cells.
Synthesize and secrete collagen fibers and other organic components of bone matrix.
Initiate the process of calcification.
Found in both the periosteum and the endosteum

29. The blue arrows indicate the osteoblasts
The blue arrows indicate the osteoblasts. The yellow arrows indicate the bone matrix they’ve just secreted.

30. Osteoclasts
Cells that _________________________– this process is called bone resorption and is part of normal bone growth, development, maintenance, and repair.
Concentrated in the endosteum.
The osteoclast secretes digestive enzymes to digest the bone matrix.
It also pumps out hydrogen ions to create an acid environment that eats away at the matrix.
Why do we want a cell that eats away at bone? (Hint: bone is a very dynamic tissue.)

31. Osteocytes Mature Bone Cells.
Osteoblasts that have become trapped by the secretion of matrix.
No longer secrete matrix.
Responsible for _________________ ________________.
Yellow arrows indicate osteocytes – notice how they are surrounded by the pinkish bone matrix.
Blue arrow shows an osteoblast in the process of becoming an osteocyte.
On the right, notice how the osteocyte is “trapped” within the pink matrix

32. Here, we see a cartoon showing all 3 cell types
Here, we see a cartoon showing all 3 cell types. Osteoblasts and osteoclasts are indicated.
Note the size of the osteoclast (compare it to the osteoblast).
What is the name of the third cell type shown here?
What do you think the tan material represents?