Anatomy Module #4 Study Guide
If a long bone has no epiphyseal plates because they have become epiphyseal lines, is there any way that a bone can grow?
Yes, it can grow wider.
There are at least six reasons bone must be continually remodeled. Can you list at least five of them?
1. Bones change mass based on stress. 2. Bone shape is changed as needed. 3. New bone tissue is always cancellous, so when compact bone tissue is needed, the cancellous has to be remodeled. 4. Bone has to be remodeled after breaking. 5. Bones are broken down to increase calcium levels in the body.
What is appositional bone growth?
Appositional bone growth is where osteoblasts lay new bone tissue on the surface of old bone tissue.
List the six major types of synovial joints in order of decreasing range of motion. Assume that pivot joints offer slightly more motion than hinge joints.
Ball-and-socket, saddle, ellipsoid, pivot, hinge, and gliding.
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?
Because the cartilage is ossified at the same rate it is made.
What is the effect of calcitonin on bone cells? What is the effect of PTH on bone cells?
Calcitonin decreases osteoclast activity, while PTH increase osteoclast activity.
Which gland secretes calcitonin? Which glands secrete PTH?
Calcitonin is secreted by the thyroid gland, and PTH is secreted by the parathyroid glands.
What are canaliculi?
Canaliculi are microscopic passageways in bone through which the extension of osteocytes run. This allows the cells in bone tissue to communicate with one another.
What kind of bone tissue contains trabeculae? What do you often find in the spaces between trabeculae?
Cancellous bone tissue is made of trabeculae. You often find red bone marrow in the spaces between trabeculae.
Looking at bone tissue under a microscope, you see no osteons. Is this compact or cancellous bone tissue?
Compact bone tissue is made of osteons. So, this is cancellous bone tissue.
A bone cell is completely surrounded by bone matrix, and how do they each affect the properties of bone tissue?
If the cell is completely surrounded by bone matrix, it is a mature bone cell. Therefore, it is an osteocyte.
What is the purpose of the synovial fluid in a synovial joint?
It lubricates the articular cartilage.
A bone cell has more than one nucleus. What kind of bone cell is it?
Only an osteoclast has more than one nucleus.
What is the term for the layers of bone tissue that form an osteon? what is the term for layers of bone between osteons?
Osteons are made of layers of tissue that form cylinders. These are called concentric lamellae. Between osteons, you find interstitial lamellae.
The epiphyseal plate separates the diaphysis from the epiphysis. On which side of the plate does the tissue ossify?
The diaphysis.
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.
Which gland secrets growth hormone, and what effect does this hormone have on bone tissue?
The anterior pituitary glands secrets GH, which stimulates bone growth by increasing osteoblast activity.
What is the purpose of the articular cartilage in a synovial joint?
To cushion the ends of the bones.
What produces synovial fluid?
The synovial membrane
What are the two principal agents in bone matrix, and how do they each affect the properties of bone tissue?
The two substances are a calcium/phosphorus mineral called hydroxyapatite and collagen. The hydroxyapatite gives the bones their hardness and compressive strength, and the collagen gives the bones some flexibility and tensile strength.
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?
Their blood calcium levels are too high.
What effect do the sex hormones have on bone growth?
They increase osteoblast activity and therefore bone growth. They also increase ossification of the epiphyseal plates.
What are the three major types of joints in the body, and which type is associated with most of the movement in the skeleton?
They three major joints are the fibrous, cartilaginous, and synovial joints. Of these the synovial joints is responsible for the majority of movement.
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 just one leg begins to twirl the lower limb that is the 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 teach side.
a. Plantar flexion b. Extension c. Circumduction d. Pronation e. Abduction
Define the following terms: a. Osteoblast b. Osteocyte c. Osteoclast d. Hematoma e. Callus f. Anatomical position
a. bone-forming cell b. A mature bone cell surrounded by bone matrix c. A large, multinucleated cell that breaks down bone d. A mass of blood that is confined to some limited space e. A mass of tissue that connects the ends of a broken bone f. The position acquired when on 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.
Label the parts of the following synovial joint illustration (pp.139).
a. bursa b. fibrous capsule c. synovial membrane d. synovial fluid in joint cavity e. articular cartilage
The following are process 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, d, c, a