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