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30 Cards in this Set
- Front
- Back
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Osteoblast |
A bone-forming cell
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Osteocyte
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A mature bone cell surrounded by bone matrix
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Osteoclast
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A large, multinucleated cell that breaks down bone
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Hematoma
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A mass of blood that is confined to an organ in some limited space
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Callus
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A mass of connective tissues that connects the ends of a broken bone
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Anatomical Position |
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 |
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What are the two principal agents in bone matrix, and how do they each affect the properties of bone tissue? |
There is collagen and hydroxyapatite--collagen gives tensile strength and some flexibility, while hydroxyapatite gives hardness and compressive strength. |
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A bone cell is completely surrounded by bone matrix. What kind of bone cell is it? |
An osteocyte. |
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A bone cell has more than one nucleus. What kind of bone cell is it? |
An osteoclast. |
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Looking at bone under a microscope, you see no osteons. Is this compact or cancellous bone tissue? |
Cancellous. |
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What kind of bone tissue contains trabeculae? What do you often find in the spaces between trabeculae? |
This must be cancellous bone, and the spaces in between trabeculae often contain red bone marrow and blood vessels. |
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What is the term for the layers of bone tissue that form an osteon? What is the term for the layers of bone between osteons? |
Concentric lamellae and interstitial lamellae. |
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What are canaliculi? |
Microscopic passageways in bone through which the extensions of osteocytes run. |
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There are at least six reasons bone must be continually remodeled. Can you list at least five of them? |
1. All new bone tissue is cancellous bone. Some new bone tissue must be compact bone, so cancellous bone often needs to be remodeled into compact bone.
2. Bones increase and decrease in mass based on the stress they experience.
3. Bones are remodeled in order to re-shape the bone as needed.
4. Bone is remodeled to repair broken bones.
5. Bone is remodeled to replace worn collagen or hydroxyapatite.
6. Bone is remodeled to regulate the calcium levels in your body. |
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Bone growth occurs when new cartilage is added to the bone's epiphyseal plate. Why doesn't the epiphyseal plate get thicker as the bone grows? |
Cartilage is ossified at the same rate at which it is added. |
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If a long bone has no epiphyseal plates because they have become epiphyseal lines, is there any way the bone can grow? |
The epiphyseal plate ossifies on the diaphysis end. |
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What is appositional bone growth? |
When osteoblasts lay new bone tissue on the surface of old bone tissue. |
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The following are the processes that occur when bone is repaired. Order them according to the sequence in which they occur.
a. The external callus is removed by osteoclasts, and cancellous bone is remodeled as needed. b. A hematoma forms. c. The callus is ossified. d. The callus forms. |
b. A hematoma forms. d. The callus is formed. c. The callus is ossified. a. The external callus is removed by osteoclasts, and cancellous bone is remodeled as needed. |
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What is the purpose of the external callus? What is the purpose of the internal callus? |
The external callus helps hold the broken pieces of bone together. The internal callus ossifies to become the new bone tissue. |
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Which gland secretes calcitonin? Which glands secrete PTH? |
The thyroid gland secretes calcitonin while the parathyroid glands secrete PTH. |
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What is the effect of calcitonin on bone cells? What is the effect of PTH on bone cells? |
Calcitonin decreases the activity of osteoclasts, while PTH increases the activity of osteoclasts. |
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A person's medical tests show a large increase in the calcitonin levels of the body. What does that tell you about the calcium level in the person's blood? |
The calcium level in the person's blood must have been too high. |
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Which gland secretes growth hormone, and what effect does this hormone have on bone tissue? |
The anterior pituitary gland secretes growth hormone, and it stimulates bone growth by increasing osteoblast activity. |
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What effect do the sex hormones have on bone growth? |
The sex hormones increase osteoblast activity, which first stimulates bone growth. However, at the same time, they stimulate ossification of the epiphyseal plates, which eventually halts bone growth, at least in terms of the length of long bones. |
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What are the three major types of joints in the body, and which type is associated with most of the movement in the skeleton? |
There are fibrous, cartilaginous, and synovial joints. Synovial joints are associated with most of the movement in the skeleton. |
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Label the parts of the following synovial joint illustration. |
a. bursa b. fibrous capsule c. synovial membrane d. synovial fluid in joint cavity e. articular cartilage |
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What is the purpose of the articular cartilage in a synovial joint? |
Articular cartilage helps the bones move smoothly inside the joint--cushions the ends of the bones with a "hard plastic" finish. |
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What is the purpose of the synovial fluid in a synovial joint? |
Synovial fluid lubricates the joint, reducing friction between the articular cartilage of the two bones. It also supports the chondrocytes in the articular cartilage and acts as a shock absorber. |
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What produces synovial fluid? |
The synovial membrane. |
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Name the kind of motion exhibited in the following actions:
a. A ballet dancer stands on tiptoe. b. A person is doing push-ups. His elbows are bent so that his body is close to the ground. He then lifts his body up by straightening his arms at the elbow. c. A gymnast who is already standing on one leg begins the lower limb that is in the air in circles. d. A person is holding his palms up and then turns his hands so that the palms point down. e. A person holds his arms down at his sides and then lifts them both up so that they are horizontal to the ground, pointing out to each side. |
a. plantar flexion b. extension c. circumduction d. pronation e. abduction |
