Chapter 5 Skeletal System

Bones are attached to the __________. a. cardiovascular system b. lymphatic system c. muscular system d. All of the listed responses are correct.

d. All of the listed responses are correct.

Which of the following is a function of the skeletal system? a. Protection b. Leverage c. Support d. All of the listed responses are correct.

d. All of the listed responses are correct.

Which of the following is the correct description of the congenital disorder of the skeleton called achondroplasia? a. It is caused by inadequate production of growth hormone before puberty, resulting in a person having normal proportions, but very short stature. b. It is caused by hypersecretion of growth hormone before puberty, resulting in a person having excessive growth. c. An abnormal gene causes excessive cartilage formation at the epiphyseal cartilages; this results in the person having extremely long and slender limbs. Another characteristic of this disorder is arterial wall weakness. d. Due to unusually slow growth of the epiphyseal cartilages in a child, affected adults have short, stocky limbs and abnormal proportions. Most cases result from spontaneous mutation.

d. Due to unusually slow growth of the epiphyseal cartilages in a child, affected adults have short, stocky limbs and abnormal proportions. Most cases result from spontaneous mutation.

Which function of the skeletal system changes the magnitude and direction of the forces generated by skeletal muscles? a. Hinges b. Support c. Protection d. Leverage

d. Leverage

Which type of fracture retains the normal alignment of the bones or fragments? a. Epiphyseal fractures b. Transverse fractures c. Pott's fractures d. Nondisplaced fractures

d. Nondisplaced fractures

Put the steps in the repair of a fracture in order. 1. The cartilage of the external callus has been replaced by bone and struts of spongy bone now unite the broken ends. Fragments of dead bone and the areas of bone closest to the break have been removed and replaced. 2. Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops. 3. A swelling initially marks the location of the fracture. Over time, this region will be remodeled, and little evidence of the fracture will remain. 4. An internal callus forms as a network of spongy bone unites the inner edges, and an external callus of cartilage and bone stabilizes the outer edges.

2, 4, 1, 3

Put the steps in endochondral ossification in order from beginning to end of the process. 1. Capillaries and osteoblasts penetrate the cartilage and invade the central region. Osteoblasts begin producing spongy bone at the primary center of ossification; bone formation then spreads along the shaft toward both ends of the cartilaginous model. 2. As the cartilage enlarges, chondrocytes near the center of the shaft increase greatly in size, the matrix is reduced to a series of small struts that soon begin to calcify, and the enlarged chondrocytes die and disintegrate, leaving cavities within the cartilage. 3. Capillaries and osteoblasts migrate into the epiphysis, creating secondary ossification centers. 4. Blood vessels grow around the edges of the cartilage, and the cells of the perichondrium convert to osteoblasts. The shaft of the cartilage then becomes ensheathed in a superficial layer of bone. 5. Epiphyses are filled with spongy bone. Articular cartilage remains exposed to the joint cavity; over time it will be reduced to a thin superficial layer. At each metaphysis, epiphyseal cartilage separates the epiphysis from the diaphysis. 6. Remodeling occurs as growth continues, and osteoclasts erode the central portion, creating a medullary cavity. The bone of the shaft becomes thicker, and the cartilage near each epiphysis is replaced by shafts of bone.

2, 4, 1, 6, 3, 5

Place the steps of appositional bone growth in order. 1. The osteon is complete with new central canal around blood vessel. Second blood vessel becomes enclosed. 2. Ridges meet and fuse, trapping the vessel inside the bone. 3. Additional circumferential lamellae are deposited, and the bone continues to increase in diameter. 4. Bone formation at the surface of the bone produces ridges that parallel a blood vessel. 5. Ridges enlarge and create a deep pocket. 6. Bone deposition proceeds inward toward the vessel, beginning the creation of a typical osteon.

4, 5, 2, 6, 3, 1

Which anatomical structures of the skeleton are complex, dynamic organs that contain osseous tissue, other connective tissue, smooth muscle, and neural tissue? a. Bones b. Joints c. Sutures d. None of the listed responses is correct.

a. Bones

The digestive system plays an important role in providing certain minerals needed for bone growth. Which mineral must be constantly provided by the digestive system, because it makes up a large portion of the bone matrix? a. Ca2 b. K+ c. Na+ d. Cl−

a. Ca2

What term is used to describe a shallow depression in bone? a. Fossa b. Ramus c. Foramen d. Tubercle

a. Fossa

Concerning the hormonal regulation of bone growth, which of the following statements is not true? a. In children and pregnant women, calcitonin inhibits osteoblasts, and decreases the rate of calcium loss in the urine. Unselected b. Parathyroid hormone stimulates osteoclast and osteoblast activity, increases the rate of calcium absorption from the small intestine, and decreases calcium loss in the urine. c. The sex hormones, estrogen and testosterone, cause osteoblasts to produce bone faster than the rate of epiphyseal cartilage expansion; eventually, the epiphyseal cartilages narrow and ossify. d. Growth hormone and thyroxine both stimulate bone growth and maintain proper epiphyseal cartilage activity until puberty.

a. In children and pregnant women, calcitonin inhibits osteoblasts, and decreases the rate of calcium loss in the urine.

Which of the following statements about intramembranous ossification is FALSE? a. It begins when mesenchymal cells differentiate into osteoclasts within embryonic or fibrous connective tissue. b. Intramembranous ossification is also known as dermal ossification. c. It normally occurs in the deeper layers of the dermis. d. Examples of intramembranous ossification include the frontal and parietal bones, the mandible, and the clavicle.

a. It begins when mesenchymal cells differentiate into osteoclasts within embryonic or fibrous connective tissue.

Which of the following statements about the periosteum is FALSE? a. It is an incomplete layer, with the thickness of one cell and with bone matrix occasionally exposed. b. It consists of an inner cellular layer containing osteoprogenitor cells. c. It is continuous with the joint capsule that encloses the joint. d. It actively participates in bone growth and repair.

a. It is an incomplete layer, with the thickness of one cell and with bone matrix occasionally exposed.

What term is used to describe a passageway through the substance of a bone? a. Meatus b. Sulcus c. Process d. Facet

a. Meatus

Which vessels form as blood vessels invade the cartilage model at the start of endochondral ossification? a. Nutrient artery and vein b. Metaphyseal vessels c. Epiphyseal vessels d. Periosteal vessels

a. Nutrient artery and vein

Which cells in bone are considered "bone-forming" because they secrete the organic components of the bone matrix? a. Osteoblasts b. Osteocytes c. Osteoid d. Osteoclasts

a. Osteoblasts

Which cell population of mature bone directs both the release of calcium from bone to blood and the deposition of calcium salts in the surrounding matrix? a. Osteocytes b. Osteoclasts c. Osteoblasts d. Osteoprogenitor cells

a. Osteocytes

What is the function of the bone cell shown below? a. Secretes acids and dissolves bone matrix b. Maintains bone matrix c. Secretes osteoid d. Divides to produce osteoblasts

a. Secretes acids and dissolves bone matrix

Name the type of fracture this x-ray image is showing: a. Spiral fracture b. Transverse fracture c. Compression fracture d. Displaced fracture

a. Spiral fracture

Which of the following statements regarding factors that regulate bone growth is FALSE? a. The active form of vitamin C, calcitriol, must be obtained from the diet. b. Vitamins A and C are essential for normal bone growth and remodeling. c. Normal bone growth requires a constant dietary source of calcium and phosphate salts, as well as other ions such as magnesium, citrate, carbonate, and sodium. d. Hormones regulate the pattern of growth by changing the rates of osteoblast and osteoclast activity.

a. The active form of vitamin C, calcitriol, must be obtained from the diet.

After the perichondrium is converted to a periosteum, the inner osteogenic layer produces a thin layer of compact bone around the shaft of the cartilage known as __________. a. bone collar b. epiphyseal plate c. articular cartilage d. metaphysis

a. bone collar

In a __________ fracture, one side of the bone shaft is broken, and the other is bent. a. greenstick b. Pott's b. comminuted c. spiral

a. greenstick

Bone growth occurs when osteoblasts are creating more bone matrix than __________ are removing. a. osteoclasts b. osteocytes c. osteoid d. osteoprogenitor cells

a. osteoclasts

During the process of endochondral ossification, a major step occurs when the centers of the epiphyses begin to calcify. Capillaries and osteoblasts migrate into these areas, creating sites called __________. a. secondary ossification centers b. articular cartilage c. epiphyseal cartilage d. primary ossification centers

a. secondary ossification centers

Immediately after a bone fracture, extensive bleeding occurs. Over a period of several hours, what develops as a result of this bleeding? a. A network of spicules b. A fracture hematoma c. An internal callus d. An external callus

b. A fracture hematoma

Which of the following statements is correct? a. Osteoblasts and osteoclasts are active during the growth years only. b. Bone remodeling involves the simultaneous process of bone resorption and bone deposition. c. In older adults, osteoblast activity exceeds that of osteoclast activity. d. In young adults, the rate of bone deposition is greater than the rate of bone resorption.

b. Bone remodeling involves the simultaneous process of bone resorption and bone deposition.

Which type of lamellae fill in the spaces between the osteons in compact bone? a. Perforating lamellae b. Interstitial lamellae c. Circumferential lamellae d. Concentric lamellae

b. Interstitial lamellae

In the formation of blood and lymphatic supply, which vessels supply blood to the diaphyseal surface of each epiphyseal cartilage, where bone is replacing cartilage? a. Epiphyseal vessels b. Metaphyseal vessels c. Periosteal vessels d. All of the listed responses are correct.

b. Metaphyseal vessels

In the classification of bones by shape, which type of bone is hollow, or contains numerous air pockets? a. Sutural bones b. Pneumatized bones c. Sesamoid bones d. Short bones

b. Pneumatized bones

Which of the following statements about the skeletal system is FALSE? a. Many bones of the skeleton can change the magnitude and direction of the forces generated by skeletal muscles. b. Red blood cells, white blood cells, and platelets are produced in the yellow marrow, which fills the internal cavities of many bones. c. Calcium is the most abundant mineral in the human body; 98 percent of the calcium in the body is deposited in the bones of the skeleton. d. Individual bones or groups of bones provide a framework for the attachment of soft tissues and organs.

b. Red blood cells, white blood cells, and platelets are produced in the yellow marrow, which fills the internal cavities of many bones.

Which of the following accurately states a difference between compact bone and spongy bone? a. Lamellae are present in compact bone only. b. Spongy bone is arranged into trabeculae. c. Osteons are present in compact bone only. d. All of the listed responses are correct.

b. Spongy bone is arranged into trabeculae.

Which type of bone consists of small, flat, oddly shaped bones that are occasionally found in the suture lines? a. Pneumatized bones b. Wormian bones c. Sesamoid bones d. Irregular bones

b. Wormian bones

Inadequate ossification is called __________. a. osteoporosis b. osteopenia c. osteomyelitis d. None of the listed responses is correct.

b. osteopenia

Put the steps of intramembranous ossification in the correct order: 1. Entrapment of blood vessels within the bone 2. Differentiation of osteoblasts within the mesenchyme 3. Formation of spongy bone 4. Formation of bony spicules a. 3, 1, 4, 2 b. 4, 2, 3, 1 c. 2, 4, 1, 3 d. 1, 4, 3, 2

c. 2, 4, 1, 3

Which diagnostic procedure would be most useful when checking for metastatic bone cancer, fractures, early infections, or certain degenerative bone diseases? a. Mri b. Arthroscopy c. Bone scan d. Arthrocentesis

c. Bone scan

Which of the following accounts for almost two-thirds the weight of bone? a. Collagen fibers b. Osteocytes and other cell types c. Calcium phosphate d. Noncollagenous proteins

c. Calcium phosphate

Which of the following is found at the ends of bones? a. Diaphysis b. Shaft c. Epiphysis d. Metaphysis

c. Epiphysis

What type of bone has thin, roughly parallel surfaces of compact bone, resembles a spongy bone sandwich, is strong but relatively light, and forms the roof of the skull, the sternum, the ribs, and scapulae? a. Sutural bones b. Irregular bones c. Flat bones d. Long bones

c. Flat bones

Which classification of bones is described as having complex shapes, with varied internal structure? a. Wormian bones b. Short bones c. Irregular bones d. Pneumatized bones

c. Irregular bones

Which of the following congenital disorders of the skeleton involves excessive cartilage formation at the epiphyseal cartilages, resulting in extremely long and slender limbs? a. Achondroplasia b. Osteomalacia c. Marfan's syndrome d. Gigantism

c. Marfan's syndrome

Which bone structure isolates and protects the bone from surrounding tissues, provides a route and a place of attachment for circulatory and nervous supply, actively participates in bone growth and repair, and attaches the bone to the connective tissue network of the deep fascia? a. Osteocytes b. Osteoprogenitor cells c. Periosteum d. Endosteum

c. Periosteum

Which vitamins are essential for normal bone growth and remodeling? a. Vitamins C and B12 b. Vitamins C and Ca2 c. Vitamins A and C d. Vitamins A and B12

c. Vitamins A and C

A bone marking called a ramus is: a. a chamber within a bone, normally filled with air b. a smooth, rounded articular process c. an extension of a bone making an angle to the rest of the structure d. a large, rough projection

c. an extension of a bone making an angle to the rest of the structure

Bones are largely under the physiological control of the __________ system. a. digestive b. urinary c. cardiovascular d. endocrine

d. endocrine

A painful and destructive bone infection generally caused by bacteria is __________. a. osteoclasts b. osteoporosis c. osteoblasts d. osteomyelitis

d. osteomyelitis