A&P 7

Compact bone:

is composed of tubular units called osteons.

The break of a bone that has been weakened by disease is a ________fracture; when a broken end of the bone pierces the skin, the fracture is ________.

pathologic, compound.

To trigger bone growth, growth hormone stimulates the:

liver to produce somatomedin.

The bones of the fingers and toes (phalanges) are categorized as _____ bones.

long

Which type of cartilage is found in the intervertebral discs?

Fibrocartilage

During appositional growth of cartilage, the cells that produce the matrix are the:

chondroblasts.

The epiphyseal plates in the _________ are the last ones in the body to ossify.

clavicle

Osteoid is the:

organic part of the bone matrix that gives it tensile strength.

As the bone matrix calcifies and the secreting cells become walled in:

osteoblasts become osteocytes.

Spongy bone:

forms diploe in the cranial bones.

This figure illustrates the cell types found in bone. Which number indicates an osteocyte?

4

Severe anemia may trigger an adaptive conversion of:

yellow marrow to red marrow.

Which is characteristic of cartilage connective tissue?

Gel-like ground substance Matrix of protein fibers Cells called chondrocytes Avascular

Which affects osteoblast and osteoclast activity?

Gravity Mechanical stress Calcitonin and parathyroid hormone levels Blood calcium level

Which is not a function of bone?

Hormone synthesis

What explains the dramatic acceleration in lengthwise bone growth at puberty?

Increased secretion of sex hormones promotes epiphyseal plate growth.

What gives bone its compressional strength?

Inorganic salts

Which is a change in bone architecture or mass related to aging?

Insufficient calcification incorrect Demineralization Reduction in the organic content of the matrix Loss of flexibility and increase in brittleness

Which is not true about periosteum?

It is composed of dense regular connective tissue.

Which is not correct about spongy bone?

It is composed of tubular units called osteons.

Which is not true about bone remodeling?

It occurs only at articular surfaces.

Consider the classifications of bone, and examples of each. Which classification comprises bones used primarily for movement rather than protection?

Long bones

Which region of a growing bone contains the epiphyseal plate?

Metaphysis

Which is not involved in the process of bone repair following a fracture?

No exceptions; all of the choices are involved in the process of bone repair.

During the process of endochondral ossification, chondrocytes in the cartilage model die. Why does this occur?

Nutrients cannot diffuse to the chondrocytes through the calcified matrix.

Which is the definition for a greenstick fracture?

Only one side of the bone is broken; the other side is bent.

If a clinician were looking to harvest bone marrow that made blood cells, which bone of a donor would be sampled?

Os coxa

Which type of cell produces new bone tissue by secreting matrix?

Osteoblasts

Which is a sesamoid bone?

Patella

Where does hemopoiesis occur?

Red bone marrow

If a bone is immersed in a weak acid such as vinegar for several days, its inorganic components will dissolve. What will be the result of such an experiment?

The bone will become soft and bendable.

What would be the effect on bone growth of insufficient dietary calcium?

The matrix would be softer.

Hyaline cartilage contains a ______ percentage of water; cartilage cells reside in small spaces called ________.

high, lacunae

Bone is ________ and contains mainly ________ nerves.

highly vascularized, sensory

Endochondral ossification begins with a(n) _________ model.

hyaline cartilage

In the kidneys, parathyroid hormone acts to ________ production of calcitriol and to ________ excretion of calcium in urine.

increase, decrease

Bone cells called __________ break down bone by secreting hydrochloric acid and enzymes that dissolve the matrix.

osteoclasts

The periosteum is anchored to the bone by collagen fibers called _____ fibers.

perforating

What are the matrix rings of compact bone that surround the central canal of each osteon?

Concentric lamellae

When during human development does the process of ossification begin?

12th-13th week of embryonic development

This figure illustrates epiphyseal plate morphology. Which is the zone of proliferating cartilage?

2

This figure illustrates the cell types found in bone. Which type of cell secretes osteoid?

2

This figure illustrates the components of compact bone. Which number indicates an osteon?

2

This figure shows the anatomy of compact bone. Which number indicates an osteon?

2

During bone repair, how long does the stage of the bony callus last?

3-4 months

This figure illustrates epiphyseal plate morphology. In which zone are minerals deposited in the matrix?

4

This figure illustrates epiphyseal plate morphology. Which zones are considered to be bone tissue?

5

This figure shows the gross anatomy of a long bone. Which number is referring to a perforating (or Volkmann's) canal?

5

What gives bone its flexibility?

Collagen fibers

Which is an alternate term for compact bone?

Cortical bone

What is the thin layer of connective tissue that lines the medullary cavity of a long bone?

Endosteum

Before beginning orthodontic treatment, a patient may have her wrist and hand x-rayed to determine her stage of growth. What long bone feature will the orthodontist use to assess this?

Epiphyseal plate

Which is an accurate description of appositional bone growth?

Osteoblasts build bone at the circumferential lamellae while osteoclasts widen the medullary cavity.

This figure illustrates the cell types found in bone. What type of cell does number 3 indicate?

Osteoclast

This figure shows the gross anatomy of a long bone. What bone feature does number 4 indicate?

Osteocyte in lacuna

Which hormone inhibits rather than stimulates bone growth?

Parathyroid hormone

Which hormone normally has a more significant effect on blood calcium levels in adults?

Parathyroid hormone

This figure illustrates the components of compact bone. Number 5 indicates passageways called

Perforating canals

Within which zone of the epiphyseal plate do cartilage cells undergo mitosis?

The second closest zone to the epiphysis

Which vitamin is required for the normal synthesis of collagen?

Vitamin C

Rickets, a disease characterized by overproduction and deficient calcification of osteoid tissue, is caused by a lack of sufficient:

Vitamin D.

Which sex tends to lose more bone mass with aging?

Women

Which bone forms by intramembranous ossification?

Zygomatic

The process of bone repair includes these steps: a: Fracture hematoma forms b: Bone is remodeled c: Fibrocartilaginous callus forms d: Bony callus forms The correct chronological order for these steps is

a - c - d - b

Bone growth in which the bone increases in diameter is called:

appositional growth.

Which choice places the steps of intramembranous ossification in correct chronological order? a: Formation of lamellar bone b: Osteoid undergoes calcification c: Ossification centers form d: Formation of woven bone and its periosteum

c - b - d - a

Place the following steps in the process of appositional growth of cartilage in correct order. a: New matrix is produced and secreted. b: Chondrocytes differentiate, each in its own lacuna. c: Stem cells undergo mitosis. d: Committed cells differentiate into chondroblasts

c. - d. - a. - b.

Bone is considered an important storage reservoir for:

calcium, phosphate, and lipids.

In compact bone, ___________ connect adjacent lacunae, thereby providing pathways for nutrients and other materials to pass between osteocytes.

canaliculi

The zones found in an epiphyseal plate are a: Calcified cartilage b: Hypertrophic cartilage c: Ossification d: Resting cartilage e: Proliferating cartilage The correct order for these zones, beginning with the edge closest to the epiphysis and proceeding toward the diaphysis, is:

d - e - b - a - c

The knobby region of a long bone at the end that is farthest from the trunk is the:

distal epiphysis.

The formation of bone from a cartilaginous model is termed:

endochondral ossification.

The steps in the process of endochondral ossification are a: Ossification center forms in the diaphysis. b: Cartilage calcifies and a bone collar forms. c: Ossification centers form in the epiphyses. d: Bone replaces cartilage. e: Epiphyseal plates ossify. f: Cartilage model develops. The correct chronological order for these steps is

f. - b. - a. - c. - d. - e.

High blood calcium and exercise cause calcitonin release to:

increase.

Calcitonin _________ osteoclast activity and _______ excretion of calcium from the kidney.

inhibits, increases

Calcidiol circulates in the blood and is converted to calcitriol in the:

kidney.

Interstitial growth of cartilage increases its ______ and occurs in the _______ region of the cartilage.

length, internal

A fracture parallel to the long axis of the bone is a(n) _________ fracture.

linear

Glucocorticoids increase bone ________; high levels of serotonin lead to _____ bone density.

loss, low

Parathyroid hormone release is triggered by _______ levels of calcium in the blood.

low

When bone forms by intramembranous ossification, the ossification centers are within:

mesenchyme

Mechanical stress of bones, such as that caused by weight lifting, is detected by:

osteocytes, which then communicate to osteoblasts to increase synthesis of osteoid.

Flat bones:

protect underlying soft tissue and may be slightly curved.

The bones of the wrist are classified as _____ bones.

short

What is the function of cartilage located in the epiphyseal plates?

site of bone elongation and growth

The type of bone tissue that is replaced more frequently is ________ bone; the part of the femur that is replaced more frequently is the __________.

spongy, distal epiphysis

An example of a flat bone would be the:

sternum (breast bone).

Parathyroid hormone and calcitriol:

stimulate osteoclasts to resorb bone and release calcium into the blood.