A&P 1- CHAPTER 6 MASTERING ASSIGNMENTS

Define appositional growth. (Module 6.6A)

Appositional growth is an increase in bone diameter due to the addition of bone matrix at the bone's outer surface.

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

It interacts with the lymphatic system to regulate calcium levels.

Which of the following is false for spongy bone? (Module 6.5C)

It makes up most of the volume of the diaphysis of long bones.

Which condition, due to excessive cartilage formation at the epiphyseal cartilages, results in individuals who are very tall, with long, slender limbs?

Marfan syndrome

In what area of a long bone would it probably be easiest to observe the cartilage the orthopedic doctor refers to?

Metaphysis

Describe the functions of osteocytes. (Module 6.4B)

Osteocytes are mature bone cells that maintain the bone matrix.

Art-labeling Activity: Surface markings of the femur and pelvis

PICTURE

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

Pott's fractures

When testosterone is increased in males at puberty, epiphyseal plates

accelerate rapidly

The trabeculae of spongy bone

are organized along stress lines.

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

calcitonin

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

head

Cells of the perichondrium need to take on a new role as ossification begins. They will become __________.

osteoblasts and begin to deposit bone matrix

Secondary ossification centers occur in

the epiphyses.

Which is the last phase of endochondral ossification?

An epiphyseal cartilage separates the epiphysis from the diaphysis.

Define osteon. (Module 6.5A)

An osteon is the functional unit of compact bone.

________ prevents damaging bone-to-bone contact within movable joints.

Articular cartilage

What type of bone growth is the doctor most likely looking for in the example above?

Endochondral ossification

Bill, age 15, is still growing, but his older sister Andrea, age 19, has stopped. What has changed in Andrea's bones?

Her epiphyseal plates have ossified.

Drag and drop the labels to the correct part during each stage of endochondral ossification.

PICTURE

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

PTH stimulation of osteoclasts

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? (Module 6.4D)

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

The cartilage the doctor is referring to will disappear when

The osteoblasts work faster than cartilage producing cells

The intestinal response to PTH secretion when calcium ion levels are low is that calcium is

absorbed quickly.

Osteocytes are embedded in a dense matrix of hydroxyapatite. Which of the following describes how osteocytes in compact bone receive nutrients?

by diffusion from nutrients released from vessels in the central canal that travel through canaliculi.

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

calcium salts

The narrow passageways that contain cytoplasmic extensions of osteocytes are called

canaliculi

A ________ fracture produces shattered bone fragments.

comminuted

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

crest

The shaft of a long bone is called the

diaphysis

The articular cartilage of a typical long bone covers portions of what part of the bone?

epiphysis

List the steps involved in fracture repair, beginning just after the fracture occurs. (Module 6.12A)

fracture hematoma formation, callus formation, spongy bone formation, compact bone formation

Remnants of osteons, which have been almost completely recycled by osteoclasts, are known as __________.

interstitial lamellae

All the following are characteristics of periosteum EXCEPT __________.

it is an incomplete cellular layer that lines the medullary cavity

Which organ prevents calcium loss in response to PTH stimulation?

kidney

As blood vessels extend into the spaces left by dying chondrocytes, the models begin to ossify internally. Where does internal ossification begin?

the primary ossification center in the diaphysis