Chapter 6 Questions
Place the following events in the correct order.
1. Chondroblasts produce a cartilage model that is surrounded by a perichondrium. 2. The perichondrium of the diaphysis becomes the periosteum, and a bony collar is produced. 3. Chondrocytes hypertrophy, die, and calcified cartilage forms. 4. A primary ossification center forms as blood vessels and osteoblasts invade. 5. Osteoblasts lay down bone matrix, forming spongy bone in the primary ossification center. 6. Secondary ossification centers form in the epiphyses of long bones. 7. The cartilage model is almost completely ossified; the remaining cartilage becomes the epiphyseal plate and articular cartilage. 8. The epiphyseal plate becomes the epiphyseal line, and all cartilage (except articular) has become bone.
Place the labels in the numbered boxes so as to accurately reflect the sequence of events of intramembranous ossification.
1. mesenchymal cells become osteochondral progenitor cells
Place the labels in the numbered boxes so as to accurately reflect the sequence of events of intramembranous ossification.
2. osteochondral progenitor cells become osteoblasts
Place the labels in the numbered boxes so as to accurately reflect the sequence of events of intramembranous ossification.
3. osteoblasts lay down bone matrix around existing collagen fibers
Place the labels in the numbered boxes so as to accurately reflect the sequence of events of intramembranous ossification.
4. osteoblasts become osteocytes as they become surrounded by bone matrix
Place the labels in the numbered boxes so as to accurately reflect the sequence of events of intramembranous ossification.
5. trabeculae of woven bone and periosteum form
Place the labels in the numbered boxes so as to accurately reflect the sequence of events of intramembranous ossification.
6. woven bone if converted to lamallar bone
Each of these factors are important for bone growth: Parathyroid hormone
False
Which of the following is associated with osteoclast reabsorption of bone?
Hydrogen ions form an acid environment in bone matrix.
A sedentary patient is low in vitamin D, and her calcium levels begin to drop. How will the body respond to bring calcium levels back to normal?
Increase parathyroid hormone secretion
Decreases blood calcium
Osteoblast activity, decreased outdoor time, calcitonin
Each of these factors are important for bone growth: Estrogen
True
Each of these factors are important for bone growth: Growth hormone
True
Each of these factors are important for bone growth: Testosterone
True
Each of these factors are important for bone growth: Thyroid hormone
True
Each of these factors are important for bone growth: Vitamin C
True
Each of these factors are important for bone growth: Vitamin D
True
Which of the following statements regarding calcium homeostasis is true?
When blood calcium levels are too low, osteoclast activity increases.
intramembranous ossification
diaphyses of the clavicles, begins with mesenchyme
Hypersecretion of parathyroid hormone may result in ____________.
elevated blood calcium levels
Each item listed here would be seen when blood calcium levels are too low: Increase in calcitonin
false
Each item listed here would be seen when blood calcium levels are too low: Increase in osteoprotegerin
false
Each item listed here would be seen when blood calcium levels are too low: Increased release of calcium from the urine
false
Each of these factors are important for bone growth: Vitamin A
false
Each of these factors are important for bone growth: Vitamin E
false
In endochondral ossification, chondroblasts produce a _________ cartilage model that has the approximate shape of the bone to be formed.
hyaline
Lack of sunlight will directly affect the formation of vitamin D. This implies that the specific cell type required for vitamin D synthesis using sunlight energy is the ___________.
keratinocyte
Osteoclast
multinucleate, bone reabsorption, releases minerals by bone breakdown
Bone cells called ___________ have processes that lie in canaliculi.
osteocytes
Sam was a 60-year-old man. As a result of picking up a heavy object, he fractured the radius and ulna of his right arm. X-rays indicated that he had severe osteoporosis. His blood calcium levels were above normal and the pathologist found cancer cells that produced a hormone-like substance. That substance was most likely
parathyroid hormone.
osteoblasts
secretes matrix, gives rise to osteocytes
Osteochondral Progenitor Cell
stem cell, gives rise to osteoblasts
Each item listed here would be seen when blood calcium levels are too low: Increase in parathyroid hormone
true
Each item listed here would be seen when blood calcium levels are too low: Increased calcium uptake in the intestine
true
Each item listed here would be seen when blood calcium levels are too low: Increased osteoclast activity
true
Each item listed here would be seen when blood calcium levels are too low: RANK activates osteoclasts.
true
Each item listed here would be seen when blood calcium levels are too low: RANKL is expressed on the surface of osteoblasts.
true
