Ch 6 Mastering
The types of fractures that are common in children are __________.
epiphyseal and greenstick
Lacunae of compact bone are occupied by mature
Osteocytes
By which week of development do most long bones have obvious primary ossification centers?
12
endochondral ossification stage 2
Calcified Matrix deteriorates
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 perichondrium is a structure that surrounds cartilage and contains the
Chondroblasts
The extracellular matrix of cartilage contains only one type of cell, which are the
Chondrocytes
The only bones formed by intramembranous ossification that are NOT in the skull are the
Clavicles
A fracture in which the bone breaks cleanly but does not penetrate the skin is a compound fracture.
False
As cartilage ages, calcium salts are deposited and mineralize the cartilage, turning it into bone.
False
Circumferential lamellae occur around the entire outer and inner surfaces of compact bone, and they are considered remnants of old osteons that have been disrupted by bone remodeling.
False
Epiphyseal plates typically close at the time an infant learns to walk.
False
In appositional growth, chondrocytes within cartilage divide and secrete new matrix. True or False
False
Type of Cartilage present in intervertebral disks
Fibro
Which of the following statements about woven bone is false? It contains no trabeculae. It is the same as spongy bone of adults. As fetal development progresses it is replaced by comapact bone at the periphery. It is characteristic of the development of embryonic flat bones.
It contains no trabeculae.
Which of the following statements about a long bone is false?
It must be more than 5 inches in length.
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.
A __________ is a layer of bone matrix in which the collagen fibers and mineral crystals align and run in a single direction.
Lamella
Daniel landed with his right arm outstretched. He heard a popping sound, and a sharp pain shot through the area just above his elbow. His brothers knew immediately that he had broken his arm. What type(s) of bone(s) could he have damaged?
Long bone
Osteoblasts originate from what type of precursor cells?
Mesenchyme Cells
Which component of bone tissue makes bone hard?
Mineral Salts
are cells that are involved in creating new extracellular matrix in bone.
Osteoblasts
Bones are continually remodeled, a process that requires that old bone matrix be broken down by
Osteoclasts
What is the effect of parathyroid hormone (PTH) on bone tissue?
PTH stimulates osteoclasts to resorb bone and release calcium into the blood when the concentration of calcium in body fluids is low.
Most bone disorders are characterized by bone loss; which of these diseases is characterized by excessive bone deposition?
Paget's disease
Which of these skeletal disorders is characterized in the later stages by excessive rates of bone deposition, where medullary cavities may fill with bony matrix?
Paget's disease
Which skeletal disorder is more common in older persons and has an abnormally high ratio of immature woven bone to mature compact bone?
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.
Functions of bones include all of the following, EXCEPT __________. blood cell formation movement protein storage mineral storage fat (energy) storage
Protein Storage
endochondral ossification stage 4
Secondary ossification centers form. Begins at or near birth.
Which statement about growth of long bones is false? The bone cannot grow longer once the epiphyseal plates are ossified. The epiphyses are pushed further from the center of the diaphysis. The epiphyseal plates remain a constant thickness during growth. The diaphysis becomes progressively thinner as the bone lengthens.
The diaphysis becomes progressively thinner as the bone lengthens.
The arrangement of the fibers and minerals in an osteon function to resist ________.
Torsion
The kneecap, or patella, is an example of
a sesamoid bone.
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
In growing cartilage, the chondroblasts associated with the perichondrium are responsible for
appositional growth.
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
In which type of fracture does the bone fragment into three or more pieces
comminuted
The cell responsible for secreting the matrix of cartilage is the
chondroblast.
The only membrane bone that occurs inferior to the skull is the
clavicle.
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 long bone that is fractured midshaft has damaged the
diaphysis.
In the bone matrix, osteoblasts become
osteocytes.
If a bone is thin, flattened, and somewhat curved, that bone is a(n) ________ bone.
flat
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
In an open reduction to repair a broken bone,
the ends are joined by pins or wires.
Osteoid is
the organic part of bone matrix prior to mineralization.
Which hormone modulates the effects of growth hormone to ensure that the skeleton remains proportional?
thyroid hormone
How long after a fracture occurs does a bony callus begin to form?
within 1 week
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.
Flat bones include all of the following examples, EXCEPT __________.
wrist bones
Which of the following is the correct progression in the healing of a skeletal fracture?
hematoma, fibrocartilage callus, bony callus, bone remodeling
Type of Cartilage present in Nose
hyaline
What is the function of the bone markings illustrated on this rib: head and facets?
surfaces that form joints
In what way does healing of cartilage occur in adults (a person who has stopped growing)?
surviving chondrocytes secrete more extracellular matrix
Which of the following statements about bones is true?
Bones grow thicker in response to the forces experienced during exercise.
endochondral ossification stage 1
Bony collar forms. Begins during week 9
Osteocytes, residing within lacunae, are connected via canaliculi.
True
Put the steps of endochondral ossification in the correct order. 1: Formation of medullary cavity and appearance of secondary ossification centers 2: Cavitation of hyaline cartilage within the cartilage model 3: Invasion of internal cavities by periosteal bud and spongy bone formation 4: Ossification of epiphyses; hyaline cartilage remains at epiphyseal plates and articular cartilages 5: Formation of bone collar around hyaline cartilage model
5,2,3,1,4
Which characteristic is a similarity among all types of cartilage? Which characteristic is a similarity among all types of cartilage? All types of cartilage lack fibers. Cartilages consist of primarily inorganic phosphates and calcium. All types of cartilages consist of 60-80% water. All types of cartilage are replaced by bone tissue.
All types of cartilages consist of 60-80% water.
Rickets most often results from a deficiency of vitamin
D.
Type of Cartilage present in external ear
Elastic
Microscopic inspection of hyaline cartilage would show prominent parallel bundles of collagen fibers. True or False
False
Type of Cartilage present in meniscus
Fibro
Type of Cartilage present in pubic symphysis
Fibro
Achondroplasia
Genetic; results in inhibition of cartilage proliferation at epiphyseal plates, and early closure of epiphyseal plates
endochondral ossification stage 5
Growth continues at epiphyseal plate. Occurs throughout childhood
The emergency room doctor expressed some concern that there might be both cartilage and bony damage to the elbow. She sent Daniel off for an X-ray. What types of cartilage might you find near the elbow?
Hyaline
Type of Cartilage present in articular cartilage of a joint
Hyaline
Type of Cartilage present in costal cartilage
Hyaline
During endochondral ossification, which of the listed types of tissue is replaced by bone?
Hyaline Cartilage
To immobilize the broken bone, Daniel's arm (including his elbow) was put in a cast. The doctor's prognosis is for a full recovery, but there is a chance that bone growth could be affected. If there is permanent damage to the growth plate, what would be the most likely outcome?
The distal end of the humerus would not grow as long as that of the undamaged left humerus. As a result, his right arm would be slightly shorter.
A sesamoid bone is a specialized short bone that develops within a tendon, such as the patella.
True
As a person ages, some calcium phosphate crystals are deposited within cartilage, leading to a condition called calcified cartilage.
True
Membrane bones form directly from mesenchyme without being modeled in cartilage.
True
Which of these is a congenital condition primarily affecting long bones?
achondroplasia
Which of these is a skeletal disorder resulting from mutations in a gene that leads to the most common form of dwarfism?
achondroplasia
Which of these results from a genetic mutation that leads to premature endochondral ossification before adult height can be reached?
achondroplasia
In an adult, the perichondrium
acts like a girdle to prevent matrix extrusion when cartilage is compressed.
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
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
Within a long bone of the skeleton, the circumferential lamellae are located in the
external and internal regions of compact bone.
The type of cartilage that can withstand the strongest compression and tension forces is
fibrocartilage.
In the repair of a simple fracture, the step that follows formation of a hematoma is
formation of fibrocartilaginous callus.
An incomplete, splintery fracture that occurs in the flexible bones of children is a(n) ________ fracture.
greenstick
What type of tissue is the embryonic precursor for long bones in the fetal skeleton?
hyaline cartilage
The type of cartilage that forms the costal cartilages at the ends of the ribs is
hyaline cartilage.
The type of cartilage that forms the long bones of the embryonic skeleton is
hyaline cartilage.
Compression and tension exerted on bones is lowest
in the medullary cavity
Repair of a simple fracture begins with
inflammation and hematoma formation.
The primary center of ossification
is in the diaphysis.
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
If a bone located in a limb is longer than it is wide, that bone is a(n) ________ bone.
long
Achondroplasia most significantly affects_________
long bones
Which factor will decrease the rate of bone resorption?
mechanical stress
Osteoblasts probably originate directly from
mesenchyme cells.
Which of the following components give rise to embryonic mesenchyme cells that then produce the membranes and cartilages that form most of the embryonic skeleton?
mesoderm germ layer and neural crest cells
Blood vessels to the diaphysis move through the
nutrient foramen.
The cartilage of the epiphyseal plates is organized into zones based upon the unique processes occurring in each of these regions. Identify the correct sequence of these processes, from the diaphysis to the epiphyseal end.
ossification - calcification - hypertrophy - growth - resting
The cell responsible for secreting the matrix of bone is the
osteoblast
Which bone cell type secretes hydrochloric acid?
osteoclast
A large, multinucleate cell with a ruffled border is an
osteoclast.
Which of the following is not present in the central canals of osteons?
osteocytes
Which of these diseases, if untreated could lead to excessively long epiphyses and bowed legs in children?
osteomalacia and rickets
Which of these would be characterized as a skeletal disorder resulting in weakened bones due to inadequate mineralization?
osteomalacia and rickets
What disease might result from a compound fracture of a bone?
osteomyelitis
What skeletal disease results from a bacterial infection of the bone and bone marrow?
osteomyelitis
Which disease of the skeletal system is often associated with decreasing levels of estrogen, but may also result from inadequate weight-bearing exercise and nutritional deficiencies of calcium, vitamin D and protein?
osteoporosis
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
The continual process of bone resorption is under the control of the
parathyroid gland.
Which hormone is primarily responsible for bone matrix resorption rather than bone matrix deposition during puberty?
parathyroid hormone
A hormone that increases the bone-degrading activity of osteoclasts is
parathyroid hormone.
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.
endochondral ossification stage 3
primary ossification center forms. begins in month 3
Mineral salts in bones _________
provide bone 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.
What is the function of the superficial (external) layer of periosteum?
resisting tension placed on bone during bending
Which of these diseases is more prevalent in children, and was exceedingly common in the United States and other industrialized nations before vitamin D was added to milk?
rickets
Bones in the wrists and ankles are
short bones.
Which of the following is not a function of the bony skeleton? production of blood cells support and protection transmission of muscular forces by acting as levers storage of parathyroid hormone
storage of parathyroid hormone
