Chapter 6: The Skeletal System - Bone Tissue

All of the following tissues are found in bone EXECPT:
a. Muscle Tissue
b. Bone
c. Dense Connective Tissue
d. Adipose Tissue
e. Nervous Tissue

Muscle Tissue

The components of the skeletal system are the...

Bones, and Cartilages associated with bones.

The skeleton does all of the following EXCEPT:
a. Supports soft tissues
b. Provides attachment points for tendons of skeletal muscles
c. Enclose and protect the brain and spinal cord
d. Stores minerals, especially calcium and phosphorous
e. Initiate movement.

Initiate movement.

What is the relationship between the skeletal system and the blood?

The bones make red blood cells, and some bones house hemopoietic tissue that makes blood.

What is found at the ends of long bones?

Articular cartilage, which is on the Epiphyses.

Which membrane lines the Medullary Cavity of a long bone?

Endosteum

Which is true about Bone Histology?
a. The primary mineral salt in bone tissue is collagen.
b. The connective tissue matrix of bone is only about 50% crystalized mineral salts.
c. The primary fiver in bone tissue is calcium phosphate
d. Calcification of the bone tissue is initiated by osteoclasts.
e. The crystalized mineral salts of bone provide its flexibility.

The connective tissue matrix of bone is only about 50% crystalized mineral salts.

Which cells would be expected to be most active in replacing bone matrix lost due to an injury?

Osteoblasts

How is Compact Bone arranged?

Arranged in units called osteeons (Haversian Systems).

All of the following are associated with compact bone EXCEPT:
a. Canaliculi
b. Osteocytes
c. Trabeculae
d. Concentric Lamellae
e. Perforating and Central Canals

Trabeculae

What structure allows communication between blood vessels and nerves in the periosteum and endosteum?

Perforating ("Volkmann's) Canals

The alignment of osteons in compact bone is (BLANK).

Is along the lines of physical stress of a long bone.

What kind of marrow does Spongy Bone contain?

Red Bone Marrow

Which is TRUE about Bone Scans?
a. Bones Scans detect uptake of a radio waves by bone tissue.
b. Hot Spots observed on bone scans show areas of decreased metabolism.
c. Cold Spots observed on bone scans show areas of increased metabolism.
d. Bone Scans are less effective that standard x-rays for detecting bone cancers.
e. Bone Scans are the standard medical imaging technique for measuring bone density.

Bone Scans are the standard medical imaging technique for measuring bone density.

What blood vessels are associated with a hole in the shaft of a long bone?

Nutrient arteries and veins.

What is the relationship of nerves and bones?

Nerves follow the blood vessels that supply the bones.

What does Bone Formation require?

Requires replacement of pre-existing connective tissue.

Place the events of Intramembranous Ossification in order:
1. Development of the Ossification Center
2. Development of the Periosteum
3. Formation of Trabeculae
4. Calcification

Order: 1, 4, 3, 2

What is formed by the Intramembranous Ossification?

Mandible (Lower Jawbone), Flat plates of the skull, and Bone that replaces soft spots on an infant skull.

When the bone matrix forms during Intramembranous Ossification, what develops?

Trabeculae develop and fuse to form Spongy Bone.

Place the events of Endochondral Ossification in ORDER:
1. Primary Ossification center development
2. Cartilage model development
3. Cartilage model growth
4. Articular Cartilage and Epiphyseal Plate formation
5. Secondary Ossification center development

Order: 2, 3, 1, 5, 4.

Compared to Intramembranous Ossification, Endochondral Ossification (BLANK).

Allows both Interstitial and Appositional Growth.

Bone increases in (BLANK).

In both length and diameter by Appositional Growth.

What does the Epiphyseal Plate consist of?

Consists of 4 zones of chondrocytes.

The zone of Hypertrophic Cartilage is (BLANK).

Is filled with large chondrocytes that are accumulating glycogen.

Place the event of Interstitial Bone Growth in ORDER:
1. Invasion of area by osteoblasts and blood vessels.
2. Death of chondrocytes.
3. Reproduction of somewhat enlarged chondrocytes occurs.
4. Calcification of cartilage matrix.
5. Maturation of chondrocytes and accumulation of glycogen.
6. Formation of new bone matrix.
7. Removal calcified matrix by osteoclasts.

Order: 3, 5, 4, 2, 1, 7, 6.

What must occur first in appositional growth of bone?

Differentiation of periosteal cells into osteoblasts.

What is required for proper bone growth?

Vitamins: A, B12, C, D, and K
Minerals: Ca and P
Hormones: IGFs, Thyroid, Growth hormones and Insulin.

Which hormone is specifically responsible for terminating growth at the epiphyseal plate in both men and women as they end adolescence?

Estrogen

Courtney is 10 years old and 183 cm til. Her parents are 173 cm and 152 tall. Adult members of the extended family have heights similar to Courtney's parents. What may account for Courtney's unusual height?

Elevated growth hormone level, and estrogen level.

Intrinsic factor, which is made by the stomach, must be present for the body to absorb vitamin B12. How might the absence of intrinsic facto affect the bones of a patient?

The resulting change in collagen synthesis might make the bones easier to fracture.

Which of the following is TRUE of Bone Remodeling?
a. It occurs only in utero (before birth).
b. It requires the activity of both osteoblasts and osteoclasts.
c. It reconstructs 50% of bone per year.
d. It occurs at the same rate in all parts of the body.
e. It causes bones to become thinner and weaker.

It requires the activity of both osteoblasts and osteoclasts.

What is the breakdown of bone matrix called?

Bone Resorption

If the rate of Bone Deposition were to exceed the rate of Bone Resorption, which of the following would probably occur?

Both bone density and bone mass would increase.

The pediatrician tells the parents that their child has a greenstick fracture. In laymen's terms, what is a greenstick fracture?

A partial break that results in one side of the broken bone bending.

Place the events of Fracture Repair in ORDER:
1. Bone Remodeling
2. Fracture Hematoma forms
3. Bony Callus forms
4. Fibrocartilaginous Callus forms

Order: 2, 4, 3, 1

Which of the following is TRUE of the Bony Callus Formation?
a. Blood clots form around the site of the fracture.
b. Fibroblasts form the periosteum form a pro callus.
c. Fibrocartilage is converted to spongy bone by osteoblasts.
d. Phagocytes secrete a collagen matrix.
e. Dead portions of bone fragment are resorbed by osteoblasts.

Fibrocartilage is converted to spongy bone by osteoblasts.

What is the goal of treating fractures?

Realignment of bone fragments, stabilization of realignment by immobilizing bones, and restoration of function.

Bone stores about ____% of the body's calcium; blood calcium levels are maintained at ____mg/100mL.

99%; 9-11mg/100mL

Why is the regulation of Ca2+ so critical to homeostasis?

Ca2+ is important for proper neuron function, and skeletal and cardiac muscle contraction.

What hormone is most important in regulating the movement of Ca2+ between the blood and the bones?

Parathyroid Hormone (PTH).

How does PTH elevate blood Ca2+ levels?

By increasing the number and activity of osteoclasts.

When calcitonin levels rise, what happens?

Osteoclast activity is inhibited.

All of the following are TRUE of Exercise and Bone EXCEPT:
a. Exercise causes increased collagen synthesis and mineral deposition in bone.
b. Adolescents should avoid weight-bearing exercises to prevent bone loos in their later years.
c. Exercise elevates calcitonin levels, thus limiting bone resorption.
d. Individuals who do not exercise tend to lose bone mass.
e. Elderly people can strengthen their bones through exercise.

Adolescents should avoid weight-bearing exercises to prevent bone loos in their later years.

Although there are certainly exceptions, the average man has more muscle mass than the average woman. How might theses differences be reflected in the skeletons of a man and a woman who are the same height, have the same nutritious diet and run the same number of miles per week?

The man's bigger muscles may create greater mechanical stress on his bones, thus stimulating his osteoblasts and making his bones denser than woman's.

All of the following are TRUE of Aging and Bone Tissue EXCEPT:
a. More bone is produced that lost during the time from birth through adolescence.
b. The rates of bone loss and gain are roughly equivalent in young adults.
c. As people age, bone production cannot keep pace with bone loss.
d. Increased calcitonin levels are largely responsible for loss of bone density with age.
e. Women may lose as much as 30% of their bone mass by the tine they reach age 70.

Increased calcitonin levels are largely responsible for loss of bone density with age.

What are the effects of aging on bone?

The loss of Ca2+ and other minerals results in demineralization and loss of bone density.
Decreased protein synthesis slows collagen production resulting in increased bone brittleness.
Loss of bone matrix may cause deformity or disability.

Does Osteoporosis afflict more with Men or Women?

Afflicts more with Women than Men.

Which of the following individuals is most likely to have Osteoporosis?
a. A 20 year-old male who smokes, binge drinks, lifts weights and runs 5 miles a week.
b. A 65 year-old man who exercises regularly, does not smoke or drink.
c. A petite, chain-smoking, sedentary 70 year-old woman of Asian-American heritage.
d. A 50 year-old woman body builder who has been competing for the last 30 years.
e. A large, physically active, non-smoking 70 year-old woman who rarely drinks alcohol.

A petite, chain-smoking, sedentary 70 year-old woman of Asian-American heritage is more likely to get Osteoporosis.

Which of the following is not common to rickets and osteomalacia?

Afflicts primarily children.