chapter 6 mastering A&P

Which of the labeled parts of the bone is composed primarily of compact bone?

D The shaft of an adult long bone is composed of compact bone.

Which of the following is the major component of the part of the bone labeled E?

E Adipose tissue Yellow bone marrow within the medullary cavity is composed primarily of adipose tissue (fat).

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

Osteoclasts are the bone cells that break down bone. If they were activated more than normal, you should expect to see bone loss.

What type of cell is shown at A?

Osteocytes, literally "bone cells," are the primary structural and maintenance cells found in bone.

spine foramen facet ramus trochanter

Spine: Sharp, slender, often pointed projection. 2. Foramen: Round or oval opening through a bone. 3. Facet: Smooth, nearly flat articular surface. 4. Ramus: Armlike bar of bone. 5. Trochanter: Very large, blunt, irregularly shaped process.

What would be the physical sign that a bone cannot continue longitudinal growth?

an epiphyseal line The epiphyseal plate is a zone of hyaline cartilage between the epiphysis and diaphysis of a long bone. When the cartilage is replaced with bone and the plate closes, the bone has reached its maximum length. This ossified remnant of the "growth plate" is called the epiphyseal line.

The figure represents a wedge-shaped section of which structural unit of bone?

an osteon The circular structural unit found within compact bone is termed the osteon, and consists of a central canal surrounded by layers of bone.

Which hormone is NOT matched with its correct function?

calcitonin; increases blood calcium levels Calcitonin is produced in the thyroid gland; it plays a minor role in regulating Ca2+ homeostasis by decreasing blood calcium levels.

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

diaphysis

At what age do bones reach their peak density?

early adulthood

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

epiphyseal plate

The pubic symphysis connects the two hip bones anteriorly and provides a little movement during childbirth. Choose the most appropriate tissue for this structure that is subjected to both pressure and stretch.

fibrocartilage

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

foramen

During infancy and childhood, the most important stimulus of epiphyseal plate activity is __________.

growth hormone During infancy and childhood, the single most important stimulus for bone growth is growth hormone. It directly stimulates growth of the hyaline cartilage that forms the epiphyseal plates in long bones, causing the bones to lengthen.

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

hematoma formation, soft callus formation, bony callus formation, and bone remodeling From start to finish, a fracture is repaired by (1) formation of a hematoma, (2) formation of a fibrocartilaginous callus, (3) formation of a bony callus, and (4) bone remodeling.

What material makes up most of the structure at A?

hyaline cartilage The articular cartilage at the ends of long bones is formed from hyaline cartilage.

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.

What is the term for the layers of bony matrix surrounding the vessels and nerve?

lamellae Lamellae are layers of bony matrix synthesized by osteoblasts during bone growth and maintenance.

Bones are constantly undergoing resorption (breaking bone down) for various reasons. Which of the following cells accomplishes this process?

osteocalst

Which of the following refers to a bone disorder found most often in the aged and resulting in the bones becoming porous and light?

osteoporosis Osteoporosis refers to groups of diseases in which bone resorption outpaces bone deposit. The bones become fragile and easily fractured. The composition of the matrix remains normal, but bone mass declines, and the bones become porous and light. Osteoporosis occurs most often in postmenopausal women.

Which hormone increases osteoclast activity to release more calcium ions into the bloodstream?

parathyroid hormone

Which of the following bones are NOT a part of the appendicular skeleton?

skull

What is intramembranous ossification?

the formation of bone from within fibrous membranes The formation of bone by ossification centers within fibrous membranes is called intramembranous ossification.

spongy bone contains

trabeculae

Which of the following is a site for a muscle or ligament attachment?

trochanter A trochanter is a type of bone projection; projections often protrude from the bone because of the interaction forced upon them by muscle or ligaments.

Hematopoiesis refers to the formation of blood cells within the red marrow cavities of certain bones.

true

Bones do NOT have a role in __________.

waste removal Waste removal is not a role of bone; it takes place primarily in kidneys.

greenstick comminuted spiral

. GreenstickAn incomplete fracture or cracking of the bone without actual separation of the parts. Common in children. 2. ComminutedBone fragments into many pieces. 3. SpiralCommon sports fracture resulting from a twisting force.

The blood vessels and nerve in the figure are found within which type of space?

centeral A central (or Haversian) canal runs lengthwise at the center of each osteon.

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.

Hypercalcemia can be caused by_________.

hypersecretion of parathyroid hormone Parathyroid hormone functions to stimulate the activity of osteoclasts in bone tissue.

What is the structural unit of compact bone?

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