Chapter 7 Skeletal System

_____________ are bone-forming cells.

B. Osteoblasts

____________ affects more people than any other bone disease.

B. Osteoporosis

If a thyroid tumor secreted an excessive amount of calcitonin, we would expect

B. an elevated level of osteoblast activity.

_______________ are common in compact bone but rarely seen in spongy bone.

D. Central canals

Calcium plays an essential role in all of the following except

D. DNA synthesis.

____________ does not put women at risk of hypocalcemia.

D. Removal of the thyroid gland

_____________ is the process of dissolving bone and returning its minerals to the bloodstream.

D. Resorption

Mature bones are remodeled throughout life by employing

D. appositional growth.

This image shows the anatomy of a long bone. What does "4" represent?

D. epiphyseal line

Which of these is an inorganic component of the bone matrix?

D. hydroxyapatite

A pathologic fracture

D. is a break in a bone weakened by some other disease.

Bone protrudes through skin in a fracture called

D. open.

A bone is covered externally with a sheath called ______________, whereas the internal surface is lined with _____________.

D. periosteum; endosteum

What would you find in the marrow cavity of the diaphysis of an adult humerus (arm bone)?

D. yellow bone marrow

____________ is synthesized by the combined action of the skin, kidneys, and liver, and is important to the deposition of bone.

E. Calcitriol

Phosphate is necessary for all of the following except

E. amino acids.

This image shows the anatomy of a long bone. What does "5" represent?

E. articular cartilage

A growing long bone in a child has only two areas of cartilage at the epiphysis. These two areas are

E. articular cartilage and epiphyseal plate.

Achondroplastic dwarfism is a hereditary condition in which the long bones of the limbs fail to elongate normally because of reduced hyperplasia and hypertrophy of cartilage in the

E. epiphyseal plate.

Patches of fibrocartilage formed in the healing of a fracture are called ________, whereas the bony collar formed around the fracture is called _________.

E. soft callus; hard callus

Hypocalcemia can cause

E. spasms

Spicules and trabeculae are found in

E. spongy bone.

A soft callus forms during

E. the healing of a fracture.

These are all tissues that are a part of a long bone except

E. transitional epithelium.

A radiograph (X-ray) of a child's hand will show epiphyseal lines.

FALSE

Bones grow in diameter by interstitial growth.

FALSE

Closed reduction is the realignment of the parts of a broken bone involving surgery.

FALSE

Concentric lamellae within an osteon are connected with each other by lacunae.

FALSE

Intramembranous ossification is common in children, whereas endochondral ossification is typical in young adults.

FALSE

Osteogenic cells are bone stem cells that differentiate into osteoblasts and osteoclasts.

FALSE

Osteomalacia results in bone brittleness.

FALSE

____________ provide(s) hardness to bones, whereas ____________ provide(s) some degree of flexibility.

A. Hydroxyapatite and other minerals; proteins

___________ have a ruffled border with many deep infoldings of the plasma membrane, whereas ____________ have long, thin, fingerlike cytoplasmic processes.

A. Osteoclasts; osteocytes

Which of the following exemplifies a positive feedback process happening in bone mineral deposition?

A. The first few crystals to form attract more calcium and phosphate

The expanded head at each end of a long bone is called

A. an epiphysis.

Which of these is not an effect of calcitriol?

A. cartilage growth in the epiphyseal plate

Bone elongation is a result of

A. cartilage growth.

Osseous tissue is a(an) ____________ tissue.

A. connective

This image shows the anatomy of a long bone. What does "1" represent?

A. marrow cavity

The _____________ is a marginal zone of the epiphyseal plate where, in children and adolescents, bone can be seen replacing the hyaline cartilage.

A. metaphysis

Intramembranous ossification produces the

B. flat bones of the skull.

Wolff's law of bone explains the effect of

B. mechanical stress on bone remodeling.

Which one of the following bone cells would have the greatest number of lysosomes?

B. osteoclasts

The result of calcium and phosphate levels in blood too low for normal deposition is a softness of the bones called ___________ in children and ___________ in adults.

B. rickets; osteomalacia

The skeleton does not

B. store red blood cells.

Red bone marrow does not contain

B. yellow bone marrow.

Chondrocytes multiply in this zone of the metaphysis.

B. zone of cell proliferation

Arteriosclerosis is one example of ectopic ossification, which means

C. abnormal calcification of a tissue.

A fracture in which the bone is broken into three or more pieces is called a __________ fracture.

C. comminuted

Osteoporosis is most common in elderly women because of the lack of ___________, which would otherwise inhibit ____________.

C. estrogen; osteoclast activity

Which of the following is the correct sequence of events in the healing of a bone fracture?

C. hematoma formation >soft callus formation > hard callus formation > bone remodeling

In endochondral ossification, the precursor connective tissue is _____________, which is replaced by bone.

C. hyaline cartilage

This image shows the histology of osseous tissue. Label "2" represents ____________, which is(are) ____________.

C. lacunae; sites of residence of osteocytes

Parathyroid hormone (PTH) does not

C. lower blood calcium.

When ____________ become enclosed in lacunae, they become cells called _____________.

C. osteoblasts; osteocytes

Blood Ca2+ deficiency stimulates __________ secretion, which leads to _____________.

C. parathyroid hormone; increased osteoclast activity

A vertebra is considered to be an irregular bone.

TRUE

Hypercalcemia causes depression of the nervous system.

TRUE

Hypercalcemia is rare but hypocalcemia can result from a wide variety of causes.

TRUE

Most blood cells are produced in the red marrow of bones.

TRUE

Osteoid tissue is similar to bone except for a lack of minerals.

TRUE

Parathyroid hormone (PTH) binds to receptors on osteoblasts.

TRUE

The hemopoietic tissue in a bone is otherwise known as myeloid tissue.

TRUE