Abnormal bone formation and reabsorption.

A) Osteomalacia
B) Paget's disease
C) Osteoporosis

B) Paget's disease

An incomplete fracture or cracking of the bone without actual separation of the parts. Common in children.

A) Comminuted
B) Spiral
C) Greenstick

C) Greenstick

Bone fragments into many pieces.

A) Comminuted
B) Spiral
C) Greenstick

A) Comminuted

Common sports fracture resulting from a twisting force.

A) Comminuted
B) Spiral
C) Greenstick

B) Spiral

The lining of the marrow cavity.

A) Endosteum
B) Canaliculi
C) Osteoblasts
D) Osteoclasts
E) Lamellae

A) Endosteum

Cells that can dissolve the bony matrix.

A) Endosteum
B) Canaliculi
C) Osteoblasts
D) Osteoclasts
E) Lamellae

D) Osteoclasts

Layers of bone matrix.

A) Endosteum
B) Canaliculi
C) Osteoblasts
D) Osteoclasts
E) Lamellae

E) Lamellae

Small channels that radiate through the matrix of bone.

A) Endosteum
B) Canaliculi
C) Osteoblasts
D) Osteoclasts
E) Lamellae

B) Canaliculi

Cells that can build bony matrix.

A) Endosteum
B) Canaliculi
C) Osteoblasts
D) Osteoclasts
E) Lamellae

C) Osteoblasts

The cells responsible for the early stages of endochondral ossification.

A) Chondrocytes
B) Appositional growth
C) Epiphyseal line
D) Diaphysis
E) Epiphyseal plate

A) Chondrocytes

The growth pattern of bone in which matrix is laid down on the surface.

A) Chondrocytes
B) Appositional growth
C) Epiphyseal line
D) Diaphysis
E) Epiphyseal plate

B) Appositional growth

The area of long bones where cartilage cells are replaced by bone cells.

A) Chondrocytes
B) Appositional growth
C) Epiphyseal line
D) Diaphysis
E) Epiphyseal plate

D) Diaphysis

The appearance of this structure signals the end of bone growth.

A) Chondrocytes
B) Appositional growth
C) Epiphyseal line
D) Diaphysis
E) Epiphyseal plate

C) Epiphyseal line

Area where bone longitudinal growth takes place.

A) Chondrocytes
B) Appositional growth
C) Epiphyseal line
D) Diaphysis
E) Epiphyseal plate

E) Epiphyseal plate

Radius.

A) Short bone
B) Long bone
C) Irregular bone
D) Flat bone
E) Sesamoid bone

B) Long bone

Carpals.

A) Short bone
B) Long bone
C) Irregular bone
D) Flat bone
E) Sesamoid bone

A) Short bone

Patella.

A) Short bone
B) Long bone
C) Irregular bone
D) Flat bone
E) Sesamoid bone

E) Sesamoid bone

Scapula.

A) Short bone
B) Long bone
C) Irregular bone
D) Flat bone
E) Sesamoid bone

D) Flat bone

Hip bones.

A) Short bone
B) Long bone
C) Irregular bone
D) Flat bone
E) Sesamoid bone

C) Irregular bone

True/False?

1) Hematopoiesis refers to the formation of blood cells within the red marrow cavities of certain
bones.

TRUE

True/False?

Compact bone is replaced more often than spongy bone.

FALSE

True/False?

Bones are classified by whether they are weight bearing or protective in function.

FALSE

True/False?

The periosteum is a tissue that serves only to protect the bone because it is not supplied with
nerves or blood vessels.

FALSE

True/False?

Short, irregular, and flat bones have large marrow cavities in order to keep the weight of the
bones light.

FALSE

True/False?

In newborn infants, the medullary cavity and all areas of spongy bone contain yellow bone
marrow.

FALSE

True/False?

The structural unit of compact bone (osteon) resembles the growth rings of a tree trunk.

TRUE

True/False?

The term osteoid refers to the organic part of the matrix of compact bones.

TRUE

True/False?

Sixty-five percent of the mass of bone is a compound called hydroxyapatite.

TRUE

True/False?

All bones formed by intramembranous ossification are irregular bones.

FALSE

True/False?

An osteon contains osteocytes, lamellae, and a central canal, and is found in compact bone
only.

TRUE

True/False?

The trabeculae of spongy bone are oriented toward lines of stress.

TRUE

True/False?

Bone tissue in the skeleton of a human fetus is completely formed at six months' gestation.

FALSE

True/False?

Each consecutive bone lamella has collagen fibers that wrap in alternating directions.

TRUE

True/False?

Cartilage has a flexible matrix that can accommodate mitosis of chondrocytes.

TRUE

True/False?

Closure of the epiphyseal plate stops all bone growth.

FALSE

The structure of bone tissue suits the function. Which of the following bone tissues is adapted to support weight and withstand tension stress?

A) spongy bone
B) irregular bone
C) compact bone
D) trabecular bone

C) compact bone

Yellow bone marrow contains a large percentage of ________.

A) fat
B) blood-forming cells
C) elastic tissue
D) Sharpey's fibers

A) fat

The cell responsible for secreting the matrix of bone is the ________.

A) osteocyte
B) osteoblast
C) osteoclast
D) chondrocyte

B) osteoblast

What kind of tissue is the forerunner of long bones in the embryo?

A) elastic connective tissue
B) dense fibrous connective tissue
C) fibrocartilage
D) hyaline cartilage

D) hyaline cartilage

What can a deficiency of growth hormone during bone formation cause?

A) inadequate calcification of bone
B) decreased osteoclast activity
C) decreased proliferation of the epiphyseal plate cartilage
D) increased osteoclast activity

C) decreased proliferation of the epiphyseal plate cartilage

A fracture in the shaft of a bone would be a break in the ________.

A) epiphysis
B) metaphysis
C) diaphysis
D) articular cartilage

C) diaphysis

The term diploë refers to the ________.

A) double-layered nature of the connective tissue covering the bone
B) fact that most bones are formed of two types of bone tissue
C) internal layer of spongy bone in flat bones
D) two types of marrow found within most bones

C) internal layer of spongy bone in flat bones

Which of the following is a bone marking name that indicates a projection that helps to form
joints?

A) meatus
B) ramus
C) foramen
D) fossa
E) epicondyle

B) ramus

Factors in preventing (or delaying) osteoporosis include ________.

A) drinking fluoridated water
B) decreasing weight-bearing exercise
C) increasing dietary vitamin C
D) decreasing exposure to the sun

A) drinking fluoridated water

Ossification of the ends of long bones ________.

A) is a characteristic of intramembranous bone formation
B) involves medullary cavity formation
C) is produced by secondary ossification centers
D) takes twice as long as diaphysis

C) is produced by secondary ossification centers

Which structure allows the diaphysis of the bone to increase in length until early childhood,
as well as shaping the articular surfaces?

A) lacunae
B) Haversian system
C) epiphyseal plate
D) epiphyseal line

C) epiphyseal plate

The most abundant skeletal cartilage type is ________.

A) hyaline
B) elastic
C) fibrocartilage
D) epiphyseal

A) hyaline

Which of the following is not a function of the skeletal system?

A) support
B) storage of minerals
C) production of blood cells (hematopoiesis)
D) communication

D) communication

What is the structural unit of compact bone?

A) osseous matrix
B) spongy bone
C) lamellar bone
D) the osteon

D) the osteon

Bones are covered and lined by a protective tissue called periosteum. The inner (osteogenic)
layer consists primarily of ________.

A) cartilage and compact bone
B) marrow and osteons
C) osteoblasts and osteoclasts
D) chondrocytes and osteocytes

C) osteoblasts and osteoclasts

The periosteum is secured to the underlying bone by dense connective tissue called
________.

A) Volkmann's canals
B) a bony matrix with hyaline cartilage
C) perforating (Sharpey's) fibers
D) the struts of bone known as spicules

C) perforating (Sharpey's) fibers

The canal that runs through the core of each osteon (the Haversian canal) is the site of
________.

A) cartilage and interstitial lamellae
B) osteoclasts and osteoblasts
C) yellow marrow and spicules
D) blood vessels and nerve fibers

D) blood vessels and nerve fibers

What are the small spaces in bone tissue that are holes in which osteocytes live called?

A) lacunae
B) Volkmann's canals
C) Haversian canals
D) trabeculae

A) lacunae

For intramembranous ossification to take place, which of the following is necessary?

A) A bone collar forms around the cartilage model.
B) An ossification center forms in the fibrous connective tissue.
C) The cartilage matrix begins to deteriorate.
D) A medullary cavity forms.

B) An ossification center forms in the fibrous connective tissue.

The process of bones increasing in width is known as ________.

A) closing of the epiphyseal plate
B) long bones reaching adult length and width
C) appositional growth
D) concentric growth

C) appositional growth

Bones are constantly undergoing resorption for various reasons. Which of the following cells
accomplishes this process?

A) osteoclast
B) osteocyte
C) osteoblast
D) stem cell

A) osteoclast

Which hormone increases osteoclast activity to release more calcium ions into the bloodstream?

A) calcitonin
B) thyroxine
C) parathyroid hormone
D) estrogen

C) parathyroid hormone

The universal loss of mass seen in the skeleton, which begins about the age of 40, ________.

A) is slower in females than in males
B) is absolutely uniform throughout the skeleton
C) reflects incomplete osteon formation and mineralization
D) is greater in African Americans than in Northern Europeans

C) reflects incomplete osteon formation and mineralization

Wolff's law is concerned with ________.

A) vertical growth of bones being dependent on age
B) the thickness and shape of a bone being dependent on stresses placed upon it
C) the function of bone being dependent on shape
D) the diameter of the bone being dependent on the ratio of osteoblasts to osteoclasts

B) the thickness and shape of a bone being dependent on stresses placed upon it

Cranial bones develop ________.

A) from cartilage models
B) within fibrous membranes
C) from a tendon
D) within osseous membranes

B) within fibrous membranes

Which of the following glands or organs produces hormones that tend to decrease blood
calcium levels?

A) pineal gland
B) thyroid
C) parathyroid
D) spleen

B) thyroid

Osteomyelitis is ________.

A) partially due to insufficient dietary calcium
B) literally known as "soft bones"
C) due to pus-forming bacteria
D) caused by altered vitamin D metabolism

C) due to pus-forming bacteria

Cartilage grows in two ways, appositional and interstitial. What is appositional growth?

A) growth at the epiphyseal plate
B) the secretion of new matrix against the external face of existing cartilage
C) along the edges only
D) the lengthening of hyaline cartilage

B) the secretion of new matrix against the external face of existing cartilage

Which of the following statements best describes interstitial growth?

A) Growth occurs in the lining of the long bones.
B) Fibroblasts give rise to chondrocytes that differentiate and form cartilage.
C) Unspecialized cells from mesenchyme develop into chondrocytes, which divide and form
cartilage.
D) Chondrocytes in the lacunae divide and secrete matrix, allowing the cartilage to grow from
within.

D) Chondrocytes in the lacunae divide and secrete matrix, allowing the cartilage to grow from
within.

In the epiphyseal plate, cartilage grows ________.

A) by pulling the diaphysis toward the epiphysis
B) by pushing the epiphysis away from the diaphysis
C) from the edges inward
D) in a circular fashion

B) by pushing the epiphysis away from the diaphysis

Spongy bones are made up of a framework called ________.

A) osteons
B) lamellar bone
C) trabeculae
D) osseous lamellae

C) trabeculae

Osteogenesis is the process of ________.

A) making a cartilage model of the fetal bone
B) bone destruction to liberate calcium
C) bone formation
D) making collagen fibers for calcified cartilage

C) bone formation

Lengthwise, long bone growth during infancy and youth is exclusively through ________.

A) interstitial growth of the epiphyseal plates
B) the secretion of bone matrix into the medullary cavity
C) differentiation of osteoclasts
D) calcification of the matrix

A) interstitial growth of the epiphyseal plates

Growth of bones is controlled by a symphony of hormones. Which hormone is important for bone growth during infancy and childhood?

A) thyroid hormone
B) somatomedins
C) growth hormone
D) prolactin

C) growth hormone

In some cases the epiphyseal plate of the long bones of children closes too early. What might
be the cause?

A) overproduction of thyroid hormone
B) elevated levels of sex hormones
C) too much vitamin D in the diet
D) osteoblast activity exceeds osteoclast activity

B) elevated levels of sex hormones

Normal bone formation and growth are dependent on the adequate intake of ________.

A) calcium, phosphate, and vitamin D
B) potassium, phosphate, and vitamin D
C) sodium, calcium, and vitamin E
D) vitamin D, phosphate, and chloride

A) calcium, phosphate, and vitamin D

Ostealgia is ________.

A) a defect called clubfoot
B) a disease of the bone
C) pain in a bone
D) fractured bone

C) pain in a bone

Blood cell formation is called ________.

hematopoiesis

A bone embedded in a tendon is called a(n) ________ bone.

sesamoid

A central (Haversian) canal may contain arteries, veins, capillaries, lymph vessels, and
________ fibers.

nerve

A long bone forms by a process known as ________ ossification.

endochondral

________ growth is growth in the diameter of long bones.

Appositional

________ are multinucleated cells that destroy bone.

Osteoclasts

________ is a disease of the bone in which bone reabsorption outpaces bone deposit, leaving the person with thin and often very fragile bones.

Osteoporosis

A round or oval hole through a bone that contains blood vessels and/or nerves is called a(n)
________.

foramen

List the steps in the repair process of a simple fracture.

Hematoma formation, fibrocartilaginous callus formation, bony callus formation, and
remodeling.

What is found in a Haversian canal?

Blood vessels and nerve fibers.

Several hormones control the remodeling of bones. Which two respond to changing blood calcium levels?

To keep bones in proper dimensions, PTH and calcitonin are the major determinants of whether and when remodeling will occur in response to changing blood calcium.

Why are the bones of young children much more flexible than those of the elderly?

Bones of children are not completely calcified, with a higher ratio of more flexible organic fibers. Bones in the elderly are more completely calcified, which gives the characteristic of rigidity.

Inflammation of bony tissue is called ________.

osteitis

Bones appear to be lifeless structures. Does bone material renew itself?

Bone only appears lifeless in gross anatomy. Microscopically, bone is full of cells and blood vessels that maintain and renew bone tissue. Approximately 5% to 7% of our bone mass is recycled each week. Up to 0.5 g of calcium may enter or leave the bones each day, depending on the negative feedback hormonal mechanism and gravitational forces.

Compare the function of the organic materials in the bone matrix with the function of the
inorganic materials in the matrix.

The organic matrix contributes to the bone structure and its tensile strength, while the
inorganic matrix contributes to hardness and resistance to compression.

What are the differences between the diaphysis and the epiphyses of long bones?

The diaphysis bone is composed almost entirely of compact bone (except in irregular and short bones), while the epiphyses are composed almost entirely of spongy bone. The epiphyses are on the ends of the bone; the diaphysis is the "shank" of the bone. The diaphysis in long bones has a large medullary cavity, whereas the epiphyses do not.

Describe how oxygen is carried from outside a bone to an individual osteocyte.

Blood vessels enter through the periosteum into a perforating canal. The vessel may follow along the axis of the bone through a central canal. Osteocytes have long, almost dendritic-like extensions or arms that reach out through tiny holes called canaliculi. The canaliculi connect one cell to another and to the central canal. Oxygen would leave the blood vessel in the central canal and travel through the canaliculi from cell to cell until it reaches the
cell in question.

How is the beginning of intramembraneous ossification different from endochondral
ossification?

Intramembraneous ossification starts in connective tissue from mesenchymal cells that become osteoblasts. These osteoblasts cluster together into an ossification center. Endochondral
ossification starts with a hyaline cartilage "template." Mesenchymal cells become osteoblasts
and begin forming bone around the cartilage.

If your doctor notices a marked decrease in calcium ion levels in your blood, what gland
might he suspect is not functioning properly and why?
Answer: T

The parathyroid gland normally responds to low calcium ion levels in the blood and releases PTH, which mobilizes osteoclasts to step up bone destruction, releasing more calcium into the bloodstream. If the parathyroid is not functioning properly it may release too much PTH or not respond at all, which seems to be the case here.

Clinical Questions
While on vacation last spring, June fell on the pavement and broke her wrist. At the emergency room, a resident placed a cast on her wrist after manipulating the bones. It seemed to heal within a few months. However, recently she has noticed lumps in the area where the break happened and she has been complaining of pain. What could be causing the lumps and the pain?

June probably has "bony spurs," which are abnormal projections from a bone due to bone overgrowth.

Clinical Questions
Alice and James adopted a 3-year-old child from a developing country. They noticed that her legs were bowed and there were some deformities in her cranial and pelvic bones. They brought her to a physician for a diagnosis. What was the diagnosis, and what was the treatment for the
disorder?

The child most likely has rickets, a condition caused by poor diet, especially one deficient in vitamin D. The parents were told to increase her intake of calcium and vitamin D and to make sure that she gets some sunshine every day.

Clinical Questions
Emily, a 64-year-old obese woman, was brought to the hospital suffering pain in her legs, and an X ray revealed that she had a simple fracture in her right femur and a crack in her left tibia. Other tests revealed that her bones were brittle and porous. What might have happened to Emily, and what advice would she have been given by the physician?

Emily has osteoporosis, a debilitating bone disease that strikes more women than men after age 45-50. The bones become weak and brittle due to leaching of calcium from the bone. Emily has been told that she needs to lose weight because her bones may not have the strength to support her body mass.

Clinical Questions
A 75-year-old woman and her 9-year-old granddaughter were victims of a train crash. In both cases, trauma to the chest was sustained. X rays of the grandmother revealed several fractured
ribs, but her granddaughter had none. Explain these different findings.

The child had more organic material in her bones, which allows them to bend, while her grandmother's bones are extensively calcified, with little organic material, and are probably thin due to osteoporosis.

Clinical Questions
Johnny fractured the lower third of his right tibia in a skiing accident. The soft tissues in the
area were severely damaged and their surgical removal was necessary. After prolonged
immobilization, it was found that Johnny was healing very poorly. The explanation offered by
the orthopedic surgeon was that vascularization of the fracture site was still inadequate and good
healing was absolutely dependent upon an adequate blood supply. Describe how a long bone receives its blood supply and trace the path of nutrient delivery to the osteocytes.

Long bones are nourished by nutrient arteries that frequently enter the shaft. Removal of the soft tissues probably reduced the flow of blood to the affected area. The pathway would include diffusion of nutrients from blood vessels to periosteum to Volkmann's canals to Haversian canals to canaliculi to lacunae.

Clinical Questions
People who live in the north should take supplemental calcium with vitamin D. Explain why.

Vitamin D is manufactured by sunlight and is needed for absorption of dietary calcium. People who live in the north where the winter months are severe may need supplemental vitamin D because of the decreased amount of sunlight exposure.

Clinical Questions
When does prevention of osteoporosis start?

The prevention of osteoporosis should begin with children. Parents need to provide children with the opportunity to develop as much bone as they have inherited the ability to develop. If people increase their peak bone mass as young adults, they will have additional protection from osteoporotic fractures in the future.

Clinical Questions
If your elderly patient's blood calcium level is normal, does that mean the patient does not
have osteoporosis? Explain.

No. The level of calcium in the blood is expected to be normal, even in advanced cases of osteoporosis. The calcium in the bones will be low, but that is not indicated by the blood nourishment.

Clinical Questions
Mrs. Brown was outside on her patio cleaning windows when she fell off her step ladder and
fractured her right hip. She had emergency surgery for an open reduction and internal fixation of
the right hip. Three days postoperative, she asks you if she will have trouble going through
airport security. What has prompted her concern?

Open reduction is the correction of the bone alignment through a surgical incision. It may include internal fixation of the fracture with the use of rods, wire, screws, pins, or nails, metal items that may trigger security alarms.

Clinical Questions
How can a tooth be moved in a bony socket during orthodontic treatment?

Because bone deposition and reabsorption can occur, and because bone responds to mechanical stress (Wolff's law), a tooth can be moved. By applying slight pressure to a tooth, the bone on the forward side will reabsorb, while the bone on the reverse side will be reformed.

Clinical Questions
Explain why swimming is not generally recommended as an exercise to prevent osteoporosis.

Mechanical stress and gravity help to promote skeletal remodeling. Swimming is not considered a weight-bearing exercise. The water, not bones, supports the body's weight while swimming.