Lecture Quiz 6: Bones and Bone Structure
the femur can withstand______times the body's weight without breaking
10 to 15
which structure is called an osteon
2
Bone is composed of ________ percent cells.
2%
which structure is a characteristic of spongy bone
5
which of the following is a function of the skeletal system
A) body support B) calcium homeostasis C) protection of internal organs D) blood cell production (all answers are correct)
which of the following does not describe treppe
An increase in stimulus intensity is required to see the effect.
For a weight to be lifted, which of the following must occur?
An isotonic muscle contraction with a force greater than the load.
Appositional and interstitial growth occurs in two different directions. Below, interstitial and appositional growths are paired with descriptions. Which of the pairings are correct?
Appositional growth: Bone gets wider. Interstitial growth: Lengthening of cartilage model Appositional growth: Bone grows at the diaphyseal surface Interstitial growth: Bone gets longer.
Bone is a type of connective tissue, with specialized cells embedded in a matrix. What does the matrix of bone consist of?
Approximately two-thirds of the weight of bone is composed primarily of calcium salts that form hard, brittle crystals of hydroxyapatite. The other major component of the bony matrix is the collagen fibers that provide tensile strength to bone.
The most abundant mineral in the human body is
Calcium
If you lift a heavy weight and hold it in your arms, close to your body, how would the bone matrix in the femur be affected?
The lateral sides of the diaphysis would stretch.
which of these cell types plays a role in bone remodeling
osteocyte, osteoblast, osteoclast (all of these are correct)
The most abundant cell type in bone is
osteocytes
The following are important steps in the process of endochondral ossification. what is the correct order for these events 1. enlarged chondrocytes die 2. osteoblasts replace calcified cartilage with spongy bone 3. chondrocytes enlarge and the surrounding matrix begins to calcify 4. blood vessels grow around the edges of the cartilage 5. perichondrial cells become osteoblasts and produce a superficial layer of bone
3, 1, 4, 5, 2
A transverse fracture of the wrist that may be comminuted is called a ________ fracture.
Colles
Why does wave summation occur?
Muscle fibers are partially contracted when the next stimulus arrives.
which of the following occurs during the latent period of isotonic concentric contraction
Muscle tension is produced, and the weight will not move.
Alex and his mother both suffer from osteogenesis imperfecta (OI), which means the imperfect formation of bone. Which bone cells are responsible for the formation of new bone matrix?
Osteoblasts are the bone cells that produce new bone matrix.
which of the following is true of osteoclasts
Osteoclasts secretes protein digesting enzymes and acids that dissolve matrix
Some older women lose height as they age. What would explain this change in stature?
Osteopenia causes compression of the vertebrae.
which of the following occurs during isotonic concentric contraction
The length of the muscle decreases with contraction.
which of the following statements regarding the homeostasis regulation of blood calcium is false?
The three main organs that serve as the site for the regulation of blood calcium levels are the bones, the intestines, and the pancreas
How do sex hormones affect bone growth?
They cause ossification to be faster than cartilage replacement.
how is vitamin D (vitamin D3) related to calcium homeostasis in bone
Vitamin D is involved in calcium absorption by the digestive tract
in normal adult bones
a portion of the protein and mineral content is replaced each year
Treppe is the phenomenon that results in _______.
a progressive increase in the force generated with repetitive stimulation
the process by which osteoblasts add layers to circumferential lamellae is
appositional growth
the trabeculae of spongy bone is
are organized along stress lines
_______ prevents damaging bone to bone contact with movable joints
articular cartilage
A bone scan of an older patient revealed the beginnings of osteoporosis. Which of these interventions is not recommended?
bed rest
The central canal of an osteon contains
blood vessels
Through the action of osteoclasts,
bony matrix is dissolved
A child with rickets would have
bowed legs
Elevated levels of calcium ion in the blood stimulate the secretion of the hormone
calcitonin
if blood calcium levels rise above 11mg/dL which hormone is likely to be activated
calcitonin
which of the following hormones is currently thought to decrease plasma calcium levels in pregnant women and children
calcitonin
PTH promotes the formation of which hormone?
calcitriol
Which hormone works directly in the intestine to increase plasma calcium levels?
calcitriol
Bone growth in length occurs by mitosis of
cartilage cells in the epiphyseal side of the metaphysis.
The condition known as osteopenia
causes a gradual reduction in bone mass
Which cells divide rapidly on the epiphyseal side at the epiphyseal plate, resulting in lengthening of the bone?
chondrocytes
which of the following produced an increase in stimulus frequency
clicking the mouse in rapid succession
An open or ________ fracture projects through the skin.
compound
in a_______fracture, the broken bone penetrates through the skin
compound
identify the structures labeled "4"
concentric lamellae
The smooth, rounded articular process of a bone is termed a
condyle
what is normally found at the site of a bone fracture
dead bone, bone fragments, and fracture hematoma (all are found at site of bone fracture)
Which portion of the developing long bone ossifies before the other portions?
diaphysis
Accelerated closure of the epiphyseal plates could be caused by
elevated levels of estrogen
what structure is necessary for a bone to grow in length
epiphyseal cartilage
the proximal and distal ends of a long bone are called the
epiphyses
one of the reasons that men can grow taller than women is because
estrogens stimulate epiphyseal closure earlier than androgens
A shallow depression on a bone is termed a
fossa
excessive growth hormone prior to puberty can result in
gigantism
When cartilage is produced at the epiphyseal side of the metaphysis at the same rate as bone is deposited on the opposite side, bones
grow longer
Alex had incurred previous fractures that were already in the process of healing when he went to the emergency room for his current injury. What is the correct sequence of events in the repair of a fracture?
hematoma formation, callus formation, spongy bone formation, and compact bone formation
A hard ossified bone in an adult actually begins within the embryo as a miniature version composed of __________.
hyaline cartilage
the articular cartilage of a typical long bone is composed of what type of cartilage
hyaline cartilage
In bone, the calcium phosphate forms crystals of
hydroxyapatite
Calcitonin does all of the following except
increase bone deposition
which of the following would not be a way that parathyroid hormone (PTH) could alter plasma calcium levels
increase osteroblasts on bone
which of the following produced an increase in stimulus intensity
increasing the voltage applied
Based on shape, a vertebra is an example of a(n) __________ bone.
irregular
RANKL or receptor activators of nuclear factor kB
is a signal molecule that stimulates osteoclasts development
Osteoclasts activating factor does all of the following except that it
is released in large amounts early in life
The humerus is an example of_____bone
long bone
bones that are relatively long and slender, consisting of a shaft with two ends are
long bones
Aging has what effect on the skeletal system?
loss of calcium and collagen fibers from matrix
There currently is no cure for OI, and treatments are often aimed at preventing or controlling symptoms. One common treatment is rodding surgery, where a metal rod is inserted into a long bone to strengthen and prevent deformity. Using what you know about the structure of a typical long bone, what part of the long bone is the most likely place for this rod to be inserted?
medullary cavity of the diaphysis
which of these is not a primary function of the skeletal system
movement
during the process of______ an existing tissue is replaced by bone
ossification
intramembranous ossification begins with differentiation of______cells
osteoblast
the lacunae of osseous tissue contain
osteocytes
stem cells that can differentiate into osteoblasts are called_____cells
osteogenic
the organic component of the matrix in developing or repairing bone is called
osteoid
what structural feature of compact bone prevents it from bending when forces are applied to either end
osteons
If osteoclasts are more active than osteoblasts, bones will become
osteopenic
A condition in which bone becomes riddled with holes making them brittle and compromises normal function is called
osteoporosis
in relationship to the diaphysis of a long bone, the osteons are
parallel
What gland responds when the blood calcium level is too low?
parathyroid gland
A drop in blood calcium levels stimulates the secretion of __________.
parathyroid hormone
intramembranous ossification
produces flat bones as in the bones of the roof of the skull.
The ongoing process of tearing down and rebuilding bone matrix is called
remodeling
The process of bone recycling and renewal is known as
remodeling
The structure labeled "3" is a result of which process
remodeling of compact bone
A lack of exercise could
result in porous and weak bones.
Roger has been lifting weights seriously for years. His twin brother Steven does not exercise regularly. Which of the following statements would be a reasonable hypothesis to make regarding differences between their skeletons?
roger's osteoblasts are more active than Steven's Roger's skeleton undergoes less osteolysis then steven's and steven's hydroxyapatite collagen combination is less than roger's
the patella is an example of an______bone
sesamoid
bones that are small, round and tend to develop in tendons are
sesamoid bones
bones that are boxy with approximately equal dimensions are
short bones
The speed of muscle contraction is called the _______.
shortening velocity
Small bones that fill gaps between bones of the skull are called ________ bones.
sutural
What is classification of this bone according to its shape
sutural
which of the following characteristics applies to the cells known as osteoclasts
the cells dissolve matrix
When wave summation occurs, _______.
the muscle force generated increases
a______is a large rough proximal projection on a bone
trochanter
a______is a smooth, grooved bone process shaped like a pulley
trochlea
A small rough bump on bone where a tendon attaches is called a
tuberosity
which of the following bones is classified as irregular in shape
vertebra
when the frequency of stimulation of a muscle is great enough
wave summation results and muscle twitches overlap.
