Chapter 6

in an adult, the perichondrium

acts like a girdle to prevent matrix extrusion when cartilage is compressed.

which of the following statements is/are true of epiphyseal plates throughout bone growth

cartilage is replaced by bone tissue on the diaphysis side as quickly as it grows, causing the epiphyseal plates to maintain a constant thickness

the cell responsible for secreting the matrix of cartilage is the

chondroblast

Cartilage repairs slowly after adolescence because

chondrocytes no longer are able to divide

the only membrane bone that occurs inferior to the skull is the

clavicle

in which type of fracture does the bone fragment into three or more pieces

comminuted

osteoporosis

compact bone becomes thinner and less dense; spongy bone has fewer trabeculae; vertebral column is most vulnerable

perforating canals within compact bone

connect the blood and nerve supply of the periosteum to that of the central canals

a fracture in which the bone breaks cleanly but does not penetrate the skin is a compound fracture

false

epiphyseal plates typically close at the time an infant learns to walk

false

microscopic inspection of hyaline cartilage would show prominent parallel bundles of collagen fibers

false

a deficiency of osteocalcin would cause

fat cells to store more fat and the pancreas to secrete less insulin

the type of cartilage that can withstand the strongest compression and tension forces is

fibrocartilage

If a bone is thin, flattened, and somewhat curved, that bone is a(n) ________ bone.

flat

a round or oval opening through a bone is a

foramen

the primary center of ossification

is in the diaphysis

which component of bone tissue makes bone hard

mineral salts the inorganic mineral salts form the hard, calcified portion of the bone matrix

blood vessels to the diaphysis move through the

nutrient foramen

the cell responsible for secreting the matrix bone is the

osteoblast

which osteogenic cells are located in the endosteum

osteoblasts because they secrete the matrix components of bone tissue

a large, multinucleate cell with a ruffled border is an

osteoclast

which bone cell type secretes hydrochloric acid

osteoclast

which of the following is not present in the central canals of osteons

osteocytes

osteomalacia

osteoid matrix is secreted, but calcification does not occur, and bones soften and weaken

which term applies to a number of disorders in adults in which the bones are inadequately mineralized

osteomalacia

what disease might result from a compound fracture of a bone

osteomyelitis

which of these diseases can be treated by administering calcitonin and calcium supplements increased weight-bearing exercise and osteoclast-inhibiting drugs

osteoporosis

which of these diseases is characterized by a pathological loss of bone density

osteoporosis

a hormone that increases the bone-degrading activity of osteoclasts is

parathyroid hormone

the kneecap, or patella, is an example of

sesamoid bone

bones in the wrists and ankles are

short bones

which of the following is not a function of bony skeleton

storage if parathyroid hormone

what is the function of the bone markings illustrated on this rib: head and facets

surfaces that form joints. heads and facets are both terms used to indicate a joint surface. many bones of the skeleton have heads, which commonly articulate with fossae. Facets are smooth, flat joints surfaces that form plane joints

in what way does healing of cartilage occur in adults (a person who has stopped growing)

surviving chondrocytes secrete more extracellular matrix

in an open reduction to repair a broken bone

the ends are joined by pins or wires

what is the effect of parathyroid hormone on bone tissue

PTH stimulates osteoclasts to resorb bone and release calcium into the blood when the concentration of calcium in body fluid is low

Rickets most often results from a deficiency of vitamin

D

Most bone disorders are characterized by bone loss; which of these diseases is characterized by excessive bone deposition?

Paget's disease

a disease that is characterized by excessive and abnormal remodeling of bone tissue and affects 3% of the elderly is

Paget's disease

which characteristic is a similarity among all types of cartilage

all types of cartilage consist of 60-80% water

the benefits of weight-bearing exercise include stronger muscles

and stronger bones

what are two locations in the body where fibrocartilage is located

annulus fibrosis of intervertebral discs and menisci of the knee

which of the following statements is true regarding the chondrocytes in the calcification zone of the epiphyseal plates of a growing person? They

are dying, leaving trabeculae on the diaphysis side of the epiphyseal plate

osteomyelitis

bacterial infection of bone and bone marrow; pathogen enters from surrounding tissue or bloodstream, or follows a compound bone fracture

which of the following statements about bones is true

bones grow thicker in response to the forced experienced during exercise

a long bone that is fractured midshaft has damaged the

diaphysis

the type of cartilage that comprises the epiglottis is

elastic cartilage

which of the following boney markings is a site for muscle attachment

epicondyle

which type of fracture tends to occur where cartilage cells are dying and the matrix is calcifying

epiphyseal

the types of fractures that are common in children are

epiphyseal and greenstick because children's bones contain relatively more organic matrix, and are more flexible than the bones of adults

after secondary ossification centers have appeared in endochondral bone, where is one of the only places on a long bone that hyaline cartilage remains

epiphyseal plates

In the repair of a simple fracture, the step that follows formation of a hematoma is

formation of fibrocartilaginous callus

achondroplasia

genetic; results in inhibition of cartilage proliferation at epiphyseal plates, and early closure of epiphyseal plates

an incomplete, splintery fracture that occurs in the flexible bones of children is an (blank) fracture

greenstick

during endochondral ossification, which of the listed types of tissue is replaced by bone

hyaline cartilage

the type of cartilage that forms the costal cartilages at the ends of the ribs is

hyaline cartilage

what is the importance of the perichondrium that surrounds cartilage

it resists outward expansion when cartilage is subjected to pressure and functions in growth and repair of cartilage

An osteon is composed of

layers of bone lamellae surrounding a central canal

rickets

leads to malformation of head and rib cage; epiphyseal plates not replaced by calcified bone; epiphyseal plates become thick

Achondroplasia most significantly affects

long bones

which factor will decrease the rate of bone resorption

mechanical stress

compression and tension exerted on bones is lowest

medullary cavity

Osteoblasts originate from what type of precursor cells?

mesenchyme cells

Muscles are not likely to tear from their bones because

perforating fibers of collagen attach the tendons and periosteum to the cortical surfaces of bone

the process of bone growth is regulated by several hormones throughout the lifetime of an individual. The hormone most influential in skeletal growth prior to adolescence is secreted from the

pituitary gland

functions of bones include all of the following EXCEPT

protein storage

mineral salts in bones

provide bone with the with the ability to resist compression

the universal loss of skeletal mass that begins after age 40

reflects an imbalance in the bone-remodeling process

which hormone modulates the effects of growth hormone to ensure that the skeleton remains proportional

thyroid hormone

the arrangement of the fibers and minerals in an osteon function to resist

torsion the alternating directions of the collagen fibers and mineral salts in each lamella add strength to bone tissue and function to resist twisting or torsional forces

Osteocytes, residing within lacunae, are connected via canaliculi.

true

as a researcher, you exploring possible ways to treat achondroplasia, Which of the following mechanisms might work in treatment

until the receptor structure of the fibroblastic grown factor is corrected, it will be difficult or impossible to correct the bone growth

a long bone is able to withstand extreme torsion or twisting stresses because

within each osteon the collagen fibers and mineral crystals in adjacent lamellae are aligned in opposite directions

how long after a fracture occurs does a bony callus begin to form

within one week

flat bones include all of the following examples, EXCEPT

wrist bones