chapter 6 A&P 1 multiple choice
Bones are constantly undergoing resorption for various reasons. Which of the following cells accomplishes this process? A) osteoclast B) osteocyte C) osteoblast D) stem cell
A
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
A
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
A
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
A
The most abundant skeletal cartilage type is ________. A) hyaline B) elastic C) fibrocartilage D) epiphyseal
A
What are the small spaces in bone tissue that are holes in which osteocytes live called? A) lacunae B) Volkmann's canals C) Haversian canals D) trabeculae
A
Yellow bone marrow contains a large percentage of ________. A) fat B) blood-forming cells C) elastic tissue D) Sharpey's fibers
A
________ growth is growth in the diameter of long bones.
Appositional
Cartilage grows in two ways, appositional and interstitial. What is appositional growth? 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
B
Cranial bones develop ________. A) from cartilage models B) within fibrous membranes C) from a tendon D) within osseous membranes Cranial bones develop ________. A) from cartilage models B) within fibrous membranes C) from a tendon D) within osseous membranes
B
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.
B
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
B
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
B
The cell responsible for secreting the matrix of bone is the ________. A) osteocyte B) osteoblast C) osteoclast D) chondrocyte
B
Which of the following glands or organs produces hormones that tend to decrease blood calcium levels? A) pineal gland B) thyroid C) parathyroid D) spleen
B
Which of the following is a bone marking name that indicates a projection that helps to form joints? A) meatus B) ramus C) foramen D) fossa E) epicondyle
B
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
B
How can a tooth be moved in a bony socket during orthodontic treatment?
Because bone deposition and reabsorption can occur, and because bone responds to mechanical stress (Wolff's law), a tooth can be moved. By applying slight pressure to a tooth, the bone on the forward side will reabsorb, while the bone on the reverse side will be reformed.
What is found in a Haversian canal?
Blood vessels and nerve fibers.
Describe how oxygen is carried from outside a bone to an individual osteocyte.
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.
Bones appear to be lifeless structures. Does bone material renew itself?
Bone only appears lifeless in gross anatomy. Microscopically, bone is full of cells and blood vessels that 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.
Why are the bones of young children much more flexible than those of the elderly?
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.
) What can a deficiency of growth hormone during bone formation cause? A) inadequate calcification of bone B) decreased osteoclast activity C) decreased proliferation of the epiphyseal plate cartilage D) increased osteoclast activity
C
A fracture in the shaft of a bone would be a break in the ________. A) epiphysis B) metaphysis C) diaphysis D) articular cartilage
C
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
C
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) somatomedins C) growth hormone D) prolactin
C
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
C
Ostealgia is ________. A) a defect called clubfoot B) a disease of the bone C) pain in a bone D) fractured 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
C
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
C
Spongy bones are made up of a framework called ________. A) osteons B) lamellar bone C) trabeculae D) osseous lamellae
C
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
C
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) concentric growth
C
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) trabecular bone
C
The term diploë refers to the ________. A) double-layered nature of the connective tissue covering the bone B) fact that most bones are formed of two types of bone tissue C) internal layer of spongy bone in flat bones D) two types of marrow found within most bones
C
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
C
Which hormone increases osteoclast activity to release more calcium ions into the bloodstream? A) calcitonin B) thyroxine C) parathyroid hormone D) estrogen
C
Which structure allows the diaphysis of the bone to increase in length until early childhood, as well as shaping the articular surfaces? A) lacunae B) Haversian system C) epiphyseal plate D) epiphyseal line
C
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
D
What is the structural unit of compact bone? A) osseous matrix B) spongy bone C) lamellar bone D) the osteon
D
What kind of tissue is the forerunner of long bones in the embryo? A) elastic connective tissue B) dense fibrous connective tissue C) fibrocartilage D) hyaline cartilage
D
Which of the following is not a function of the skeletal system? A) support B) storage of minerals C) production of blood cells (hematopoiesis) D) communication
D
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.
D
Emily, a 64-year-old obese woman, was brought to the hospital suffering pain in her legs, and an X ray revealed that she had a simple fracture in her right femur and a crack in her left tibia. Other tests revealed that her bones were brittle and porous. What might have happened to Emily, and what advice would she have been given by the physician?
Emily has osteoporosis, a debilitating bone disease that strikes more women than men after age 45-50. The bones become weak and brittle due to leaching of calcium from the bone. Emily has been told that she needs to lose weight because her bones may not have the strength to support her body mass.
A long bone forms by a process known as ________ ossification.
Endochondral
A round or oval hole through a bone that contains blood vessels and/or nerves is called a(n) ________.
Foramen
List the steps in the repair process of a simple fracture.
Hematoma formation, fibrocartilaginous callus formation, bony callus formation, and remodeling.
How is the beginning of intramembraneous ossification different from endochondral ossification?
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.
While on vacation last spring, June fell on the pavement and broke her wrist. At the emergency room, a resident placed a cast on her wrist after manipulating the bones. It seemed to heal within a few months. However, recently she has noticed lumps in the area where the break happened and she has been complaining of pain. What could be causing the lumps and the pain?
June probably has "bony spurs," which are abnormal projections from a bone due to bone overgrowth.
Johnny fractured the lower third of his right tibia in a skiing accident. The soft tissues in the area were severely damaged and their surgical removal was necessary. After prolonged immobilization, it was found that Johnny was healing very poorly. The explanation offered by the orthopedic surgeon was that vascularization of the fracture site was still inadequate and good healing was absolutely dependent upon an adequate blood supply. Describe how a long bone receives its blood supply and trace the path of nutrient delivery to the osteocytes.
Long bones are nourished by nutrient arteries that frequently enter the shaft. Removal of the soft tissues probably reduced the flow of blood to the affected area. The pathway would include diffusion of nutrients from blood vessels to periosteum to Volkmann's canals to Haversian canals to canaliculi to lacunae.
Explain why swimming is not generally recommended as an exercise to prevent osteoporosis. .
Mechanical stress and gravity help to promote skeletal remodeling. Swimming is not considered a weight-bearing exercise. The water, not bones, supports the body's weight while swimming.
If your elderly patient's blood calcium level is normal, does that mean the patient does not have osteoporosis? Explain.
No. The level of calcium in the blood is expected to be normal, even in advanced cases of osteoporosis. The calcium in the bones will be low, but that is not indicated by the blood nourishment.
Mrs. Brown was outside on her patio cleaning windows when she fell off her step ladder and fractured her right hip. She had emergency surgery for an open reduction and internal fixation of the right hip. Three days postoperative, she asks you if she will have trouble going through airport security. What has prompted her concern?
Open reduction is the correction of the bone alignment through a surgical incision. It may include internal fixation of the fracture with the use of rods, wire, screws, pins, or nails, metal items that may trigger security alarms.
________ are multinucleated cells that destroy bone.
Osteoclast
________ is a disease of the bone in which bone reabsorption outpaces bone deposit, leaving the person with thin and often very fragile bones.
Osteoporosis
A 75-year-old woman and her 9-year-old granddaughter were victims of a train crash. In both cases, trauma to the chest was sustained. X rays of the grandmother revealed several fractured ribs, but her granddaughter had none. Explain these different findings.
The child had more organic material in her bones, which allows them to bend, while her grandmother's bones are extensively calcified, with little organic material, and are probably thin due to osteoporosis.
Alice and James adopted a 3-year-old child from a developing country. They noticed that her legs were bowed and there were some deformities in her cranial and pelvic bones. They brought her to a physician for a diagnosis. What was the diagnosis, and what was the treatment for the disorder?
The child most likely has rickets, a condition caused by poor diet, especially one deficient in vitamin D. The parents were told to increase her intake of calcium and vitamin D and to make sure that she gets some sunshine every day.
What are the differences between the diaphysis and the epiphyses of long bones?
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; the diaphysis is the "shank" of the bone. The diaphysis in long bones has a large medullary cavity, whereas the epiphyses do not.
Compare the function of the organic materials in the bone matrix with the function of the inorganic materials in the matrix.
The organic matrix contributes to the bone structure and its tensile strength, while the inorganic matrix contributes to hardness and resistance to compression.
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?
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.
When does prevention of osteoporosis start?
The prevention of osteoporosis should begin with children. Parents need to provide children with the opportunity to develop as much bone as they have inherited the ability to develop. If people increase their peak bone mass as young adults, they will have additional protection from osteoporotic fractures in the future.
Several hormones control the remodeling of bones. Which two respond to changing blood calcium levels?
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.
People who live in the north should take supplemental calcium with vitamin D. Explain why.
Vitamin D is manufactured by sunlight and is needed for absorption of dietary calcium. People who live in the north where the winter months are severe may need supplemental vitamin D because of the decreased amount of sunlight exposure.
Blood cell formation is called ________.
hematopoiesis
A central (Haversian) canal may contain arteries, veins, capillaries, lymph vessels, and ________ fibers.
nerve
Inflammation of bony tissue is called ________.
osteitis
A bone embedded in a tendon is called a(n) ________ bone
sesamoid
