Condition where bones are porous and thin but bone composition is normal
Disease where bone formed is poorly mineralized and soft. Deforms on weight-bearing
Abnormal bone formation and reabsorption
An incomplete fracture or cracking of the bone without actual separation of the parts. Common in children
Bone fragments into many pieces
Common sports fracture resulting from a twisting force
The lining of the marrow cavity
Cells that can dissolve the bony matrix
Layers of bone matrix
Small channels that radiate through the matrix of bone
Cells that can build bony matrix
The cells responsible for the early stages of endochondral ossification
The growth pattern of bone in which matrix is laid down on the surface
The area of long bones where cartilage cells are replaced by bone cells
The appearance of this structure signals the end of bone growth
Area where bone longitudal growth takes place
T or F: Hematopoiesis refers to the formation of blood cells within the red marrow cavities of certain bones
T or F: Compact bone is replaced more often than spongy bone.
T or F: Bones are classified by whether they are weight-bearing or protective in function.
T or F: The periosteum is a tissue that serves only to protect the bone because it is not supplied with nerves or blood vessels.
T or F: Short, irregular, and flat bones have large marrow cavities in order to keep the weight of the bones light.
T or F: In newborn infants, the medullary cavity and all areas of spongy bone contain yellow bone marrow.
T or F: The structural unit of compact bone (osteon) resembles the growth rings of a tree trunk.
T or F: The term osteoid refers to the organic part of the matrix of compact bones.
T or F: Sixty-five percent of the mass of bone is a compound called hydroxyapatite.
False; flat bones
T or F: All bones formed by intramembranous ossification are irregular bones.
T or F: An osteon contains osteocytes, lamellae, and a central canal, and is found in compact bone only.
T or F: The trabeculae of spongy bone are oriented toward lines of stress.
False; childhood to adolescence
T or F: Bone tissue in the skeleton of a human fetus is completely formed at six months' gestation.
T or F: Each consecutive bone lamella has collagen fibers that wrap in alternating directions.
T or F: Cartilage has a flexible matrix which can accomodate mitosis of chrondrocytes.
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)
Yellow bone marrow contains a large percentage of ________. A)
blood-forming cells C)
elastic tissue D)
The cell responsible for secreting the matrix of bone is the ________. A)
What kind of tissue is the forerunner of long bones in the embryo? A)
elastic connective tissue B)
dense fibrous connective tissue C)
decreased proliferation of the epiphyseal plate cartilage
In bone formation, a deficiency of growth hormone will cause ________. A)
inadequate calcification of bone B)
decreased osteoclast activity C)
decreased proliferation of the epiphyseal plate cartilage D)
increased osteoclast activity
A fracture in the shaft of a bone would be a break in the ________. A)
the internal layer of spongy bone in flat bones
The term diploë refers to ________. A)
the double-layered nature of the connective tissue covering the bone B)
the fact that most bones are formed of two types of bone tissue C)
the internal layer of spongy bone in flat bones D)
the two types of marrow found within most bones
The sternum (breastbone) is a good source of blood-forming tissue.
Select the correct statement concerning the location of blood-forming tissue. A)
There is blood-forming marrow in the diaphysis of most long bones of an adult. B)
The sternum (breastbone) is a good source of blood-forming tissue. C)
There is blood-forming marrow in most short bones of an adult. D)
Blood-forming tissue is found in the skull and pelvic bones only.
drinking fluoridated water
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
is produced by secondary ossification centers
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
high water content
Cartilage is found in strategic places in the human skeleton. What is responsible for the resilience of cartilage? A)
high water content B)
hydroxyapatite deposits C)
calcium influx D)
The most abundant skeletal cartilage type is ________. A)
Which of the following is (are) not the function(s) of the skeletal system? A)
storage of minerals C)
production of blood cells (hematopoiesis) D)
The structural unit of compact bone is ________. A)
osseous matrix B)
spongy bone C)
lamellar bone D)
osteoblasts and osteoclasts
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
Perforating (Sharpey's) fibers
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
blood vessels and nerve 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
The small spaces in bone tissue that are holes in which osteocytes live are called ________. A)
Volkmann's canals C)
Haversian canals D)
An ossification center forms in the fibrous connective tissue
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.
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)
Bones are constantly undergoing resorption for various reasons. Which of the following cells accomplishes this process? A)
Which hormone increases osteoclast activity to release more calcium ions into the bloodstream? A)
parathyroid hormone D)
Vertebrae are considered ________ bones. A)
reflects incomplete osteon formation and mineralization
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
A bone fracture perpendicular to the bone's axis is called a(n) ________ fracture. A)
the thickness and shape of a bone being dependent on stresses placed upon it
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
within fibrous membranes
Cranial bones develop ________. A)
from cartilage models B)
within fibrous membranes C)
from a tendon D)
within osseous membranes
Which of the following glands or organs produces hormones that tend to decrease blood calcium levels? A)
pineal gland B)
due to pus-forming bacteria
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
the secretion of new matrix against the external face of existing cartilage
Cartilage grows in two ways, appositional and interstitial. Appositional growth is ________. 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
Chondrocytes in the lacunae divide and secrete matrix, allowing the cartilage to grow from within
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.
by pushing the epiphysis away from the diaphysis
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
Spongy bones are made up of a framework called ________. A)
lamellar bone C)
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
interstitial growth of the epiphyseal plates
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
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)
growth hormone D)
elevated levels of sex hormones
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
Electrical signals direct the remodeling process.
It is thought that remodeling or bone growth is in response to the forces placed on it. Which of the following hypotheses may explain how mechanical forces communicate with cells responsible for bone remodeling? A)
Increase in the synthesis of growth hormone directs the remodeling process. B)
Vitamin D enhances the remodeling process. C)
Bone deposition by osteoclasts is responsible for remodeling. D)
Electrical signals direct the remodeling process.
calcium, phosphate, and vitamin D
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
Which fracture would be least likely in a 92-year-old? A)
_____________ are not one of the four cell types that populate bone tissue in adults. A)
Mesenchymal cells C)
pain in a bone
Ostealgia is ________________. A)
a defect called clubfoot B)
a disease of the bone C)
pain in a bone D)
A fracture in which a bone is broken into many pieces would be classified as a ________ fracture.
Blood cell formation is called ________.
A bone embedded in a tendon is called a ________ bone.
A central (Haversian) canal may contain arteries, veins, capillaries, lymph vessels, and ________ fibers.
A narrow slitlike opening in bones is called a ________ .
A long bone forms by a process known as ________ ossification.
________ growth is growth in the diameter of long bones.
________ are multinucleated cells that destroy bone.
________ is a disease of the bone in which bone reabsorption outpaces bone deposit, leaving the person with thin and often very fragile bones.
A round or oval hole through a bone that contains blood vessels and/or nerves is called a ________.
Hematoma formation, fibrocartilaginous callus formation, bony callus formation, and remodeling.
List the steps in the repair process of a simple fracture.
Blood vessels and nerve fibers.
What is found in a Haversian canal?
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.
Several hormones control the remodeling of bones. Which two respond to changing blood calcium levels?
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.
Why are the bones of young children much more flexible than those of the elderly?
Inflamation of bony tissue is called ________.
Bone only appears lifeless in gross anatomy. Microscopically, bone is full of cells and blood vessels which 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.
Bones appear to be lifeless structures. Does bone material renew itself?
The organic matrix contributes to the bone structure and its tensile strength, while the inorganic matrix contributes to hardness and resistance to compression.
Compare the function of the organic materials in the bone matrix with the function of the inorganic materials in the matrix.
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 while the diaphysis is the "shank" of the bone. The diaphysis in long bones has a large medullary cavity while the epiphyses do not.
What are the differences between the diaphysis and the epiphyses of long bones?
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.
Describe how oxygen is carried from outside a bone to an individual osteocyte.
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.
How is the beginning of intramembraneous ossification different from endochondral ossification?
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.
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?
at epiphyseal plates
At the end of secondary ossification, hyaline cartilage can be found: