Chapter 6 Homework Flashcards
Which of the following bones is accurately described as an irregular bone?
*Vertebra
Rib
Metacarpal bone
Radius
An expanded joint surface shaped like a ball and found on the articular end of the epiphysis is called a __________.
condyle
facet
trochlea
*head
A large, rounded, articulating (relating to joints) process of bone is a _________.
*condyle (large, rounded, articulating)
tubercle (small, rounded)
tuberosity (rough projections)
trochanter (large, rough)
Changing the magnitude and direction of forces generated by skeletal muscles is an illustration of the skeletal function of __________.
- leverage - Changing the magnitude and direction of forces generated by skeletal muscles is an illustration of the function of leverage.
energy reserve in bones
storage capability of bones
protection
A smooth, grooved articulating process of bone shaped like a pulley is a ___________.
trochlea
Thin bones that form the roof of the skull, the sternum, and the scapulae are considered ________.
flat bones
Where is a sesamoid bone most often found?
near joints at the knees, hands, and feet
Depressions, grooves, and tunnels in bone indicate __________.
where blood vessels or nerves lay alongside or penetrated bones
Mature bone cells found in lacunae are called __________.
osteocytes
The process of bone breakdown or erosion is called __________.
osteolysis
The meshwork of supporting bundles of fibers that make up spongy bone are __________.
trabeculae
Which of the following types of bone cells are responsible for removing and recycling bone?
Osteoclasts
Which component of the bone stores energy?
yellow marrow - adipose tissue
Found in this medullary cavity is yellow marrow. This yellow marrow is predominately adipose tissue. This is an important energy reserve for the body.
One function of bone is to produce red and white blood cells. These cells are made in what substance in bone?
Red marrow
Which of the following is an effect of stress on a bone?
The bone will become thicker.
Our bodies get bigger and heavier, which puts more stress on our bones. Furthermore, if we are active, even more stress is applied. To compensate for the effects of stress, the bone will become thicker. However, the opposite is also true. If the stress on a bone decreases (for example, when a broken leg is placed in a cast for six weeks), the bone will become weaker. There is a direct relationship between amount of stress and bone thickness.
Which of the following are NOT structural components of compact bone?
Trabeculae
Unlike compact bone, spongy bone (also called cancellous bone) resembles a network of bony struts separated by spaces that are normally filled with __________.
bone marrow
The spaces made by the irregular pattern of struts in spongy bone are normally filled with bone marrow, which functions to produce blood cells or store lipids.
Two-thirds of a bone’s weight is composed of calcium phosphate which interacts with calcium hydroxide to form crystals of __________.
hydroxyapatite
Which of the following statements about bone tissue is FALSE?
*It is made primarily of cells.
It contains collagen.
It is made primarily of calcium phosphate.
It contains four different cell types.
Bone is an unusual substance. It is composed of proteins (collagen) and mineral crystals (calcium phosphate). Once ossified, bone has a tensile strength that is four to eight times stronger than reinforced concrete. This hard matrix—which supports and protects soft tissue, aids in movement, and produces red blood cells—is the product of four different cell types. But these cell types make up only 2 percent of the total skeletal system. Therefore, osseous tissue is NOT made up primarily of cells; rather, the cooperation among these cells yields the bone matrix.
The term for the expanded end of a long bone where the joint surfaces are located is the __________.
epiphysis
As osteoclasts absorb and remove bone matrix, they leave shallow depressions called a(n) _________.
meatus
lamella
ruffled border
*osteoclastic crypt
As osteoclasts resorb bone they release acid. The release of acid and degrading enzymes dissolves the matrix and creates an osteoclastic crypt (Howship’s lacunae). The osteoclastic crypt develops a ruffled border to increase the surface area to increase the erosion process. A meatus is a tube-like passageway in a bone and lamellae are the layers seen in osteons.
Giant, multinucleated cells involved in the process of osteolysis are __________.
osteoclasts
Even as an adult, we have populations of primitive cells that can produce osteoblasts. These primitive cells are called __________.
osteogenic cells
Compact bone is characterized by many cylindrical osteons. Osteons are formed by layers of nested cylinders each called a(n) _____________.
osteocyte
*lamella
canaliculus
lacuna
Compact bone is composed of multiple osteons each of which is composed of cylinders called lamellae (plural for lamella). These lamellae are named differently for their location (e.g., circumferential are around the outer edge of bone and interstitial lamellae for the space filling layers found between osteons). Most lamellae are concentric lamellae which surround the central canals of osteons. Osteocytes are bone cells found in lacunae and communicate through small cytoplasmic extensions called canaliculi.
Unlike compact bone, spongy bone (also called cancellous bone) resembles a network of bony struts separated by spaces that are normally filled with __________.
?
Narrow passageways that allow osteocytes to communicate with neighboring osteocytes are called _____________.
osteons
central canals
*canaliculi
lacuna
Canaliculi are narrow passageways that allow for communication with neighboring cells. Although surrounded by osteoid, osteocytes must still receive oxygen and nutrients, get rid of waste products, and respond to hormones. Canaliculi allow for the rapid exchange of ions and smaller molecules. Lacunae are the pockets in which osteocytes reside. Osteons are the functional units of bone. Central canals are passageways that carry blood vessels and nerves within bone.
The basic functional unit(s) of compact bone tissue is/are __________.
an osteon
Cells that produce new bone matrix are called __________.
osteoblasts
The spaces in the bony matrix where osteocytes exist are __________.
lacunae
The small passageways that exist in the bone matrix to allow living bones cells to obtain nutrients and get rid of wastes are called __________.
lacunae
canals
*canaliculi
foramina
Canals that extend perpendicularly through bone to supply blood to deeper osteons and to tissues of the medullary cavity are ___________________ canals.
interstitial lamellae
*perforating
central
Howship’s
Perforating canals (also called Volkmann’s canals) extend perpendicularly to the surface of compact bone. These canals allow osteons to be connected one to another, supply blood to deeper osteons, and supply tissue of the medullary cavity. Central canals run parallel to the long axis of osteons. Interstitial lamellae fill the spaces between osteons and Howship’s lacunae are the shallow pits caused by osteoclasts during bone resorption.
Appositional growth on the outer surface of bones results in __________.
an increase in the diameter of a growing bone
The result of overproduction of growth hormone before puberty can result in a condition called ___________.
gigantism
The result of overproduction of growth hormone after puberty can result in a condition called ___________.
acromegaly
Which bones are not formed by intramembranous ossification?
*Bones of the appendages
Flat bones of the skull
Mandible
Clavicles
The process of replacing other tissues with bone is called __________.
ossification
The bony skeleton begins to form about __________ after fertilization and usually does NOT stop growing until about age __________ years.
six weeks; 25
What is the major advantage or advantages of bones undergoing continual remodeling?
It may change the total amount of minerals deposited in the bones.
*All of the listed responses are correct.
It may change the shape of a bone.
It may change the internal structure of a bone.
In which of the following does bone replace existing cartilage?
Endochondral ossification
Appositional growth __________.
increases the diameter of a long bone, forms circumferential lamellae, and involves both osteoblasts and osteoclasts
What type of tissue is replaced by bone in intramembranous ossification?
Mesenchyme or embryonic fibrous connective tissue
The outer dense connective tissue of a bone, the periosteum, ________.
isolates the bone from surrounding tissues, provides a route for circulatory and nervous supply, and actively participates in bone growth and repair
The fibers of tendons intermingle with those of the periosteum, attaching __________.
skeletal muscles to bones
What is the term for the process in which the organic and mineral components of bone are continuously recycled and renewed?
Remodeling
How is the tendon connected to a bone so that it will withstand the force that must be applied by the muscle to move the bone?
The collagen fibers of the tendon as well as the periosteum are incorporated into the bone tissue.
The periosteum is a membrane with a fibrous outer layer and an inner cellular layer. The fibers of the periosteum are interwoven with those of the tendons attached to the bone. As the bone grows, those tendon fibers, as well as fibers from the periosteum, are cemented into circumferential lamellae by osteoblasts from the cellular layer of the periosteum. This method of attachment bonds the tendons into the general structure of the bone, providing a much stronger attachment than would otherwise be possible. This allows the muscle to apply large amounts of force to the bone and cause movement.
A tall, slender person with unusually long, slender limbs because of excess cartilage formation at the epiphyseal cartilages has what disorder?
Marfan’s syndrome
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
The endosteum is found in all of the following places except the __________.
covering the outside surface of the bones
In endochondral ossification, blood vessels penetrate and invade the central region of the cartilaginous model. This first area that is invaded is called the __________.
primary ossification center
The presence of which structure is a clear indication that the person has reached their adult height and has stopped growing?
Epiphyseal line
Which statement concerning endochondral ossification is the most accurate?
The ends of the cartilage rod are converted into bone first.
*A primary ossification center begins replacing cartilage in the central region of the cartilage rod.
A bone collar forms around the ends of the cartilage rod.
The epiphyseal plate is an area of bone that joins the shaft of the cartilage rod to the ends of the rod.
Calcitonin does all of the following except ____________________.
decrease intestinal absorption of calcium
decrease osteoclast activity
increase excretion of calcium by the kidneys
*increase osteoblast activity
Calcitonin is released when calcium levels rise above 11 mg/dL in the blood. Calcitonin does decrease osteoclast activity, decrease intestinal absorption of calcium, and increase calcium excretion all in an attempt to lower blood calcium levels. Calcitonin does not increase osteoblast activity.
Fractures that shatter a bone into many small fragments are called __________ fractures.
comminuted
Parathyroid does all of the following except __________.
increase the activity of osteoblasts
Parathyroid hormone (PTH) is released when calcium levels drop below 8.5 mg/dL in the blood. PTH increases osteoclast activity, increases intestinal absorption of calcium, and decreases calcium excretion all in an attempt to raise blood calcium levels. PTH does not increase osteoblast activity which would have the effect of lowering the calcium levels even more.
Darcy wrecks her bike and experiences a break in the distal portion of her radius, which now projects out of her skin. Which type of fracture does she have?
an open Colles’ fracture
Which of the following is not brought about by parathyroid hormone?
Increased absorption of calcium by the small intestine
Increased osteoclast activity
Decreased rate of excretion of calcium by the kidneys
*Decreased production of calcitriol
What is the term for a reduction in bone mass that is large enough to compromise the normal function of bone?
Osteoporosis
as we age, everyone will have some form of osteopenia. Recall that with this condition, osteoblast activity starts to slow, while osteoclast activity remains the same. However, if osteoblast activity decreases very rapidly, then the loss of bone matrix can compromise the normal bone function. If this happens, then the person has osteoporosis. With osteoporosis, the bones become perforated with holes, fragile, and break easily.
Bone stores ____% of body’s calcium and phosphate.
99%
The hormone synthesized in the kidneys that regulates absorption of calcium and phosphate ions in the digestive tract is __________
calcitriol
If the level of calcium in the blood drops below normal levels, which hormone is produced to correct this homeostatically?
Parathyroid hormone
The type of fracture that occurs in vertebrae that are subject to extreme stresses is a __________ fracture.
compression
If an abnormal rearrangement or alignment of the bones results from a fracture, it is called a __________ fracture.
displaced
A fracture of the ankle where both the distal ends of the tibia and fibula broken is called a ________ fracture.
Pott’s
When the calcium ion concentration of the blood rises above the normal level, secretion of the hormone calcitonin __________.
increases the rate of calcium ion excretion from the kidneys
A fracture in which one side of the shaft is broken and the other side is bent is a __________.
greenstick fracture