Study Guide
1. Define the following terms:
a. Osteoblast – A bone cell which produces bone matrix
b. Osteocye – a mature bone cell which is surrounded by bone matrix
c. Osteoclast – a large, multi-nucleated cell which breaks down the bone matrix and osteoblasts so that new bone tissue may be formed
d. A localized mass of blood that is confined to an organ or some definable space
e. A mass of tissue that connects the ends of bones
f. The position acquired when one stands erect with the feet facing forward, the upper limbs hanging at the sides, and the palms facing forward with the thumbs to the outside
2. Collagen proteins and the mineral compound hydroxapatite. The protein fibers provide the bone with tensile strength and flexibility, while hydroxapatite gives the bone compressional strength.
3. It is an osteocyte.
4. It is an osteoclast.
5. It is cancellous bone tissue.
6. Cancellous bone tissue contains trabeculae, the beams of the bone, which blood vessels and red bone marrow run through.
7. Concentric lamellae form osteons, while interstitial lamellae are between osteons.
8. Narrow channels in the bone matrix that are filled with the extensions of bone cells. These extensions allow the bone cells to come into direct contact with each other and communicate with one another.
9. Firstly, all new bone is cancellous bone tissue, therefore while you are growing, it is important for compact bone to form in places where it is necessary. Another reason is that the bones need to bear a different amount of weight throughout the lifespan of a human being, depending on various factors such as their activity level and age. Also, collagen fibers in the bone will wear and need to be replaced with fresh fibers. The hydroxapatite will deteriorate as well as the collagen, and also needs to be replaced. When a bone breaks, bone remodeling is a part of bone repair. It is also important because bone remodeling determines the amounts of certain minerals which are in the bloodstream.
10. Because the cartilage is simultaneously ossified.
11. The diaphysis.
12. Yes…the bone can expand and grow thicker.
13. It is bone growth in which the bone does not lengthen but thickens.
14. B, d, c, a.
15. The callus holds the broken bone together. The internal callus eventually forms the new bone, while the external callus is there only for stability and will be eaten away once the bone is reformed.
16. The thyroid secretes calcitonin, and the parathyroid secretes PTH.
17. Calcitonin checks the activity of osteoclasts, while PTH stimulates the activity of osteoclasts.
18. Their calcium level is most likely far too high.
19. The anterior pituitary gland secretes HGH, which stimulates the growth of bones by increasing osteoblast activity.
20. When they burst onto the scene, they stimulate a flurry of bone growth by increasing osteoblast activity, but after a while, they bring bone growth to a close because they cause the bones to mature by causing the epiphiseal plates to ossify.
21. Fibrous joints, cartilaginous joints, and synovial joints. The synovial joints are responsible for movement.
22.
a. bursa
b. fibrous capsule
c. synovial membrane
d. synovial fluid
e. articular cartilage
f. inner periosteum
g. outer periosteum
23. To keep the bones within the joint from grinding against one another.
24. To lubricate the joint.
25. The synovial membranes.
26. Ball and socket joint, ellipsoid joint, saddle joint, hinge joint, pivot joint, plane joint.
27.
a. plantar flexion
b. extension
c. circumduction
d. pronation
e. abduction
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