Chapter 6

The adult skeleton contains ________ major bones.

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Where is articular cartilage found, and how is it nourished? (Module 6.3C)

Articular cartilage is found covering both epiphyseal portions of articulating bone and nutrients diffuse from synovial fluid within the joint.

The most abundant mineral in the human body is

Calcium

A transverse fracture of the wrist that may be comminuted is called a ________ fracture.

Colles

How does calcitonin act to lower blood calcium? (Module 6.11C)

Decreases osteoclast break down of bone matrix, decreases calcitriol production, decreases intestinal absorption, and increases renal excretion

Define endochondral ossification

Endochondral ossification is the replacement of a cartilage model with bone.

Compare gigantism with acromegaly. (Module 6.9C)

Gigantism results from an overproduction of growth hormone before puberty, whereas acromegaly results from an overproduction of growth hormone after puberty.

Which of the following is not true of the skeletal system?

It interacts with the lymphatic system to regulate calcium levels.

Describe the functions of osteocytes. (Module 6.4B)

Osteocytes are mature bone cells that maintain the bone matrix.

Describe the functions of osteogenic cells and osteoblasts. (Module 6.4A)

Osteogenic cells are stem cells that form osteoblasts. Osteoblasts are immature bone cells that secrete the organic components of bone matrix.

All the following result in decreased calcium levels in the bloodstream EXCEPT __________.

PTH stimulation of osteoclasts

Ankle fractures that affect both bones of the leg are called __________.

Pott's fractures

A ________ fracture is produced by twisting stresses applied to the bone.

Spiral

Describe the axial and appendicular divisions of the skeleton. (Module 6.1A)

The axial skeleton consists of the bones of the skull, vertebral column, and thorax. The appendicular skeleton consists of the bones of the limbs, pectoral girdle and pelvic girdle.

If osteoclast activity exceeds osteoblast activity in a bone, how will bone mass be affected?

The bone mineral content will decrease and thus bone mass will decrease.

Describe the function of the medullary cavity. (Module 6.3B)

The medullary cavity contains the red bone marrow and the yellow bone marrow.

Excessive growth hormone after puberty could result in

acromegaly.

In compact bone, the osteons are

arranged in concentric lamellae

The central canal of an osteon contains

blood vessels

Elevated levels of calcium ion in the blood stimulate the secretion of the hormone

calcitonin.

Which substance accounts for almost two-thirds of the weight of bone?

calcium salts

Endochondral ossification begins with the formation of a(n)

cartilage model.

A ________ fracture produces shattered bone fragments.

comminuted

An open, or ________, fracture projects through the skin.

compound

The fracture of vertebrae subjected to extreme vertical stress is called a ________ fracture.

compression

The smooth, rounded articular process of a bone is termed a

condyle.

A prominent ridge, as seen on the pelvis, is a

crest

The shaft of a long bone is called the

diaphysis

The lining of the medullary cavity is called the

endosteum

Secondary ossification centers occur in

epiphyses

List the major parts of a long bone. (Module 6.3A)

epiphysis, metaphysis, diaphysis, and medullary cavity

A rib is an example of a ________ bone.

flat

Identify the six broad categories for classifying a bone according to shape.

flat, sutural, long, irregular, sesamoid, short

A ________ is a rounded passageway for passage of blood vessels and/or nerves.

foramen

A rounded hole through a bone is termed a

foramen

A shallow depression on a bone is termed a

fossa

Damage to a bone because of extreme load, sudden impact, or stresses applied from an unusual direction is called a

fracture.

Which of the following describes spiral fractures?

fractures that are produced by twisting stresses that spread along the length of the bone

The expanded articular end of an epiphysis that is separated from the shaft by a narrower neck is termed a

head

Which of the following is true for parathyroid hormone?

inhibits calcitonin secretion.

All the following are characteristics of periosteum EXCEPT __________.

it is an incomplete cellular layer that lines the medullary cavity

The humerus is an example of a(n) ________ bone.

long bone

Fat is stored within the

medullary cavity

The region of a long bone between the end and the shaft is known as the

metaphysis.

the opening in the diaphysis through which blood vessels provide oxygen to osteons is named the ________ foramen.

nutrient

The lacunae of osseous tissue contain

osteocytes

Identify the hormone that stimulates the release of calcium ions from bone matrix. Explain its mechanism of action. (Module 6.11A)

parathyroid hormone; increases osteoclast break down of bone matrix

A projection at an angle on a bone is termed a(n) ________

ramus

Which class of bones develops inside tendons and is most commonly located near joints at the knees, the hands, and the feet?

sesamoid bones

The carpal bones are examples of ________ bones.

short

A chamber within a bone normally filled with air is

sinus

Which of the following is not a function of the skeletal system?

temperature regulation

Which of the following are not components of the skeletal system?

tendons

A small rough bump on bone where a tendon attaches is called a

tuberosity.