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.