A&P lab exercise 8

Your patient is returning for follow-up 6 weeks after sustaining a nondisplaced fracture of his radius. He tells you that his forearm is no longer painful, but he is concerned that he can palpate a "lump" in the bone at the site of the healing fracture. What is your response?

"That bump is a normal part of bone healing at this stage. As your body completes the process, the cells in your bone will gradually remodel it to its previous shape."

Which event has to proceed all others during endochondral ossification?

A cartilage model of the bone is formed.

Which of the following statements best describes interstitial growth of cartilage?

Chondrocytes in the lacunae divide and secrete matrix, allowing the cartilage to grow from within.

Which description of skeletal cartilage is INCORRECT?

Costal cartilages reinforce airways and support the external nose. Respiratory cartilages form the skeleton of the larynx (voice box) and reinforce other respiratory passageways. Costal cartilages connect the ribs to the sternum.

Which of the following statements is true? Endochondral ossification occurs within fibrous connective tissue membranes. During endochondral ossification, hyaline cartilage is broken down and replaced with bone. Most bones in the body are formed by intramembranous ossification. Endochondral ossification leads to the formation of the clavicles and cranial bones.

During endochondral ossification, hyaline cartilage is broken down and replaced with bone. Endochondral ossification is the formation of bone within hyaline cartilage. Beginning late in the second month of development, this process uses hyaline cartilage "bones" formed earlier as models, or patterns, for bone construction. It is more complex than intramembranous ossification because the hyaline cartilage must be broken down as ossification proceeds. Most bones below the base of the skull form by endochondral ossification.

The main role of the axial skeleton is to help us manipulate our environment.

False It is the appendicular skeleton, along with the skeletal muscles that attach to it, that allows us to manipulate our environment. The axial skeleton is mostly involved in protecting, supporting, or carrying other body parts.

Which statement regarding the classification of bones is FALSE? The sternum is an example of a flat bone. Sesamoid bones form within certain tendons. Irregular bones include the vertebrae and hip bones. Long bones include all limb bones except the patella.

Long bones include all limb bones except the patella. This is false; long bones include all limb bones except the patella, tarsals, and carpals.

Which description of bone cells is INCORRECT?

Osteogenic cells can differentiate into osteoclasts.

Which statement regarding osteons is FALSE?

Osteons are found in all bone tissues

Which of the following statements regarding the skeleton is INCORRECT? The axial skeleton includes the bones of the limbs. The appendicular skeleton allows us to move around. The axial skeleton supports and protects internal organs. The appendicular skeleton includes the shoulder girdles.

The axial skeleton includes the bones of the limbs. The bones of the limbs makeup the appendicular skeleton.

What is the structural unit of compact bone?

The structural unit of compact bone is the osteon, an elongated cylinder oriented parallel to the long axis of the bone.

You are counseling a patient with osteoporosis about strategies for avoiding fractures. Which of the following comments would NOT be appropriate?

You should avoid weight-bearing exercise and strength training because these types of exercise will further weaken your bones Remember that Wolff's law states that bone density increases in response to mechanical stress. Appropriate activity is an essential component of the treatment for this condition.

The axial/ appendicular skeleton consists of bones that surround the body's center of gravity.

axial

All the following are functions of the skeleton except: a. attachment for muscles b. production of melanin c. site of red blood cell formation d. storage of lipids

b. production of melanin

The central (Haversian) canal that runs through the core of each osteon is the site of ________.

blood vessels and nerve fibers

What tissue forms the model for endochondral ossification?

cartilage

A fracture in the shaft of a bone would be a break in the ________.

diaphysis

the shaft of the bone is called the ____________.

diaphysis

Which structure allows the diaphysis of the bone to increase in length until early childhood?

epiphyseal plate

the end of a long bone is called ___________.

epiphysis

Closure of the epiphyseal plate stops all bone growth.

false

The hormone that is primarily involved in the control of bone remodeling is calcitonin.

false

The type of cartilage that has the greatest strength and is found in the knee joint and intervertebral discs is:

fibrocartilage

Which of the following is a bone marking described as a round or oval opening through a bone?

foramen

Which of the following is UNLIKELY to affect bone remodeling?

glucagon Glucagon's main action is to increase blood glucose levels by triggering the breakdown of glycogen in the liver; it does not affect bone remodeling.

Which of the following is the single most important stimulus for epiphyseal plate activity during infancy and childhood?

growth hormone

The central canal in an osteon is also called the __________.

harversian canal

The correct order (from start to finish) of fracture repair is __________.

hematoma formation, soft callus formation, bony callus formation, and bone remodeling

Which of the following contributes most directly to the hardness of bones?

hydroxyapatite Hydroxyapatite, or mineral salts such as calcium phosphate, accounts for the most notable characteristic of bone—its exceptional hardness, which allows it to resist compression.

At the epiphyseal plate, which zone is characterized by older cartilage cells that are enlarging?

hypertrophic zone

The hardness of bone is due to __________.

inorganic calcium-salt deposits

When chondrocytes in lacunae divide and form new matrix, it leads to an expansion of the cartilage tissue from within. This process is called __________.

interstitial growth Interstitial growth occurs when chondrocytes divide and form new matrix, thereby expanding the cartilage tissue from within.

Ossification of the ends of long bones ________.

is characterized by secondary ossification

What did the acid treatment do to the structure of the bone?

it dissolved the minerals in the bone matrix

In a cross section of compact bone, where are osteocytes found?

launae

Bone projections include __________.

muscle and ligament attachment sites

The process of bone formation is also called __________.

ossification

The cell responsible for secreting the matrix of bone is the ________.

osteoblast

A homeostatic imbalance that activates these bone cells would lead to a loss of bone density.

osteoclasts

The mature bone cell found in compact bone tissue is the __________.

osteocyte

The structural unit of compact bone is the:

osteon or haversian system

The periosteum is secured to the underlying bone by ________.

perforating (Sharpey's) fibers

Osteoid-producing osteoblasts must rely on this organelle to produce primary structures leading to the formation of collagen and calcium-binding proteins.

ribosomes

The resilience of bone is thought to come from which of the following?

sacrificial bonds in or between collagen molecules

Bone tissue that is composed of trabeculae (columns) of bone and a lot of open space is classified as __________.

spongey

Which of the following pairs of terms is mismatched? tarsals: short bones sternum: long bone cranial bones: flat bones femur: long bone

sternum: long bone

What is intramembranous ossification?

the formation of bone from within fibrous membranes

Cartilage grows in two ways, appositional and interstitial. What is appositional growth?

the secretion of new matrix against the external face of existing cartilage

Choose which bone marking type would likely increase in size when a weight lifter repeatedly exercises muscles that attach to it.

trochanter

The structural unit of compact bone (osteon) resembles the growth rings of a tree trunk.

true

The term osteoid refers to the organic part of the matrix of compact bones without mineralization.

true

Flat bones consist of a thin plate of spongy bone, called diploë, sandwiched between two layers of compact bone.

true Flat bones consist of thin plates of spongy bone (diploë) covered by compact bone.

Bones do NOT have a role in __________.

waste removal

What fills the central (medullary) cavity of the shaft of a long bone in an adult?

yellow marrow