1. Define the following terms:
a. Osteoblast - A bone forming cell.
b. Osteocyte - A mature bone cell surrounded by bone matrix.
c. Osteoclast - A large, multi-nucleated cell that breaks down bone.
d. Hematoma - A localized mass of blood that is confined to an organ.
e. Callus - A mass of tissue that connects the ends of a broken bone.
f. Anatomical position - The position acquired wen 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. The two principal agents in bone matrix are collagen and hydroxyapatite. Collagen provides tensile strength and flexibility. Hydroxyapatite, a mix of calcium and phosphorous, gives the bone its hardness and compressive strength.
3. the bone cell is an osteocyte.
4. This bone cell is an osteoclast.
5. This is compact bone tissue.
6. Cancellous bone tissue contains trabeculae. The spaces in between the trabeculae contain red bone marrow and blood vessels.
7. The layers of tissue that construct an osteon are called concentric lamellae. The layers of tissue between the osteons is called interstitial lamellae.
8. Canaliculi are the extensions on osteocytes that allow them to communicate with one another.
9. Six reasons bone must be remodelled :
a. Some cancellous bone ossifies into compact bone.
b. Due to stress, bone mass can increase or decrease.
c. If the bone needs to be re-shaped, it will remodel.
d. Bone will remodel if any worn out collagen or hydroxyapatite needs to be replaced.
e. Bone will remodel to repair broken bones.
f. Bones will remodel to regulate calcium levels.
10. As calcium salts accumulate in the cartilage, the chondrocytes start to die, leaving behind holes. Blood vessels fill these holes, bringing in osteoblasts and osteoclasts. The osteoblasts start laying bone matrix on top of the cartilage, forming new cancellous bone.
11. The tissue ossifies near the diaphysis.
12. The bone cannot grow in length, but it get thicker.
13. Appositional growth is the process by which osteoblasts lay new tissue on top of old tissue.
14. b, d, c, a.
15. The external callus stabilizes the bone while it is being healed. The internal callus forms the new bone tissue.
16. The thyroid gland secretes calcitonin. Parathyroid glands secrete PTH.
17. Calcitonin decreases the activity of osteoclasts. PTH increases the activity of osteoclasts.
18. The calcium level in the patient's blood is too high.
19. The anterior pituitary gland secretes the human growth hormone, which stimulates tissue growth.
20. Sex hormones increase the activity of osteoblasts, stimulating bone growth. They also cause the epiphyseal plates in long bones to ossify, which eventually causes bone to stop growing.
21. The 3 major types of joints are fibrous joints, cartilaginous joints, and synovial joints. Synovial joints are associated with most movement in the body.
22. Label the following structures:
a. bursa
b. fibrous capsule
c. synovial membrane
d. synovial fluid
e. articular cartilage
f. inner layer of the periosteum
g. outer layer of the periosteum
23. In a synovial joint, articular cartilage covers the ends the bone to prevent damage.
24. Synovial fluid lubricates the joint, reducing friction.
25. The synovial membrane produces synovial fluid.
26. The six major types of synovial joints in order of decreasing range of motion:
Ball and socket, ellipsoid, saddle, hinge, pivot, and plane.
27. a. plantar flexion
b. extension
c. circumduction
d. pronation
e. abduction
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