Chapter 6 Anatomy

__________bone reduces the weight of the skeleton and reduces the load on muscles.

Spongy

How do sex hormones affect bone growth?

They cause ossification to be faster than cartilage replacement.

The deposition of calcium salts in bone tissues is referred to as

calcification

If blood calcium levels rise above 11mg/dL which hormone is likely to be activated?

calcitonin

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

calcitonin

Which hormone increases calcium and phosphate ion absorption by the intestines?

calcitrol

Bones play a central role in the regulation of blood levels of:

calcium

the most abundant mineral in the human body is

calcium

________ account(s) for almost two-thirds of the weight of bone.

calcium phosphate

The narrow passageways that contain cytoplasmic extensions of osteocytes are called:

canaliculi

Bone growth in length occurs by mitosis of

cartilage cells in the epiphyseal side of the metaphysis.

Endochondral ossification begins with the formation of a(n) (what kind of model?)

cartilage model

The layers of bone tissue immediately deep to the periosteum are

circumferential lamellae

Of the total organic components in bone, most of it is:

collagen

A ________ fracture shatters the bone.

comminuted

An open or ________ fracture projects through the skin.

compound

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

compression

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

condyle

After a fracture of the diaphysis has healed, the thickened region that results is called the

external callus

A rib is an example of a ________ bone.

flat

A rounded passage or hole through a bone is called a:

foramen

a shallow depression on a bone is termed a:

fossa

Excessive growth hormone prior to puberty could result in

gigantism

In a ________ fracture one side of the shaft is split and the other side is bent.

greenstick

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

head

The articular cartilage of a typical long bone is composed of what type of cartilage?

hyaline cartilage

What type of tissue is replaced in the embryo during endochondral ossification?

hyaline cartilage

In bone, the calcium phosphate forms crystals of

hydroxyapatite

Bones that have complex shapes are:

irregular

The space occupied by an osteocyte is called:

lacuna

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

long

Adipose tissue is stored within the

medullary cavity

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

metaphysis

Canaliculi are:

narrow passageways in the matrix connecting lacunae to blood supply

Cells that secrete protein fibers in bone are called:

osteoblasts

Cells that secrete the organic components of the bone matrix are called

osteoblasts

Cells that are found in small depressions on the endosteal surfaces are the:

osteoclasts

Cells that free calcium from bone to maintain blood calcium levels are called

osteoclasts

The most abundant cell type in bone is

osteocytes

Stem cells that can differentiate into osteoblasts are called:

osteogenic

The structural units of mature compact bone are called

osteons

In relationship to the diaphysis of a long bone, the osteons are:

parallel

The superficial membrane of a bone is called the

periosteum

intramembranous ossification

produces flat bones, as in the bones of the roof of the skull.

The ________ interactions allow bone to be strong, somewhat flexible, and highly resistant to shattering.

protein-crystal

The ongoing process of tearing down and rebuilding bone matrix is called

remodeling

A lack of exercise could

result in porous and weak bones

Bones that are small, round and tend to develop in tendons are

sesamoid

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

sesamoid

_____ bones develop inside tendons, commonly near the knees, hands, and feet.

sesamoid

The carpal bones are examples of ________ bones.

short

A(n) ______, or closed, fracture, does not break the skin.

simple

A chamber within a bone normally filled with air is a:

sinus

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

spiral

The type of bone that is adapted to withstand stresses that arrive from many directions is ________ bone

spongy

Small bones that fill gaps between bones of the skull are called ________ bones.

sutural

The femur can withstand _____ times the body's weight without breaking.

10-15

Bone is composed of ________ percent cells.

2

Of the total inorganic components in bone, calcium accounts for what percent?

39%

Which of the following is a characteristic of bone? A) The bone matrix is very dense and contains deposits of calcium salts. B) The matrix of the bone contains osteoclasts and chondroblasts. C) Narrow channels pass through the matrix to allow for muscle attachment. D) The matrix of bone is mostly collagen with very little calcium. E) For strength, compact bone is organized into a meshwork of matrix called trabeculae.

A) The bone matrix is very dense and contains deposits of calcium salts.

Which of the following are not components of the skeletal system? A) tendons B) bones C) ligaments D) cartilage E) other tissues that connect bones

A) tendons (part of the muscular system)

__________ prevents damaging bone-to-bone contact within movable joints:

Articular cartilage

factors that are necessary for proper bone formation include all of the following except: A) vitamin A. B) vitamin E. C) vitamin C. D) the hormone thyroxine. E) vitamin D.

B) vitamin E.

The following are major steps in the process of intramembranous ossification: 1. Clusters of osteoblasts form osteoid that becomes mineralized. 2. Osteoblasts differentiate within mesenchymal connective tissue. 3. Spicules of bone radiate out from the ossification centers. 4. Mesenchymal cells aggregate. What is the correct order for these events? A) 4, 1, 2, 3 B) 2, 1, 3, 4 C) 4, 2, 1, 3 D) 2, 3, 1, 4 E) 3, 4, 2, 1

C) 4, 2, 1, 3

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

Colles

Which of the following chemicals is not present in bone? A) calcium phosphate B) collagen fibers C) calcium carbonate D) chondroitin sulfate E) hydroxyapatite

D) chondroitin sulfate

Parathyroid hormone functions in all of the following ways except: A) stimulating osteoclast activity. B) increasing the rate of calcium absorption. C) decreasing the rate of calcium excretion. D) raising the level of calcium ion in the blood. E) inhibiting calcitonin secretion.

E inhibiting calcitonin secretion

The following are important steps in the process of endochondral ossification. What is the correct order for these events? 1. Enlarged chondrocytes die. 2. Osteoblasts replace calcified cartilage with spongy bone. 3. Chondrocytes enlarge and the surrounding matrix begins to calcify. 4. Blood vessels grow around the edges of the cartilage. 5. Perichondrial cells become osteoblasts and produce a superficial layer of bone. A) 3, 1, 5, 4, 2 B) 1, 3, 5, 4, 2 C) 1, 5, 3, 4, 2 D) 2, 3, 1, 5, 4 E) 3, 1, 4, 5, 2

E) 3, 1, 4, 5, 2

Which of the following is formed by intramembranous ossification? A) roof of the skull B) carpal bones C) femur D) clavicle E) the roof of the skull and the clavicle

E) the roof of the skull and the clavicle

Which of following is a function of the skeletal system? A) body support B) calcium homeostasis C) protection of internal organs D) blood cell production E) All of the answers are correct.

E: All of the answers are correct

________ are stem cells that develop into osteoblasts.

Osteogenic

________ cells are located in the inner cellular layer of the periosteum.

Osteogenic

A fracture at the ankle involving both lower leg bones is often called a ________ fracture.

Pott's

A fracture that affects the malleolus on both lower leg bones is called a ________ fracture.

Pott's

_______ marrow is found between the trabeculae of spongy bone.

Red

In normal adult bones,

a portion of the mineral protein is replaced each year

The process by which osteoblasts add layers to circumferential lamellae is

appositional growth

When production of sex hormones increases at puberty, epiphyseal plates

become narrower

The central canal of an osteon contains

blood vessels

Through the action of osteoclasts,

bony matrix is dissolved

If blood calcium levels drop below 8.5 mg/dL which hormone is likely to be activated?

both calcitrol and parathyroid hormone

A child with rickets often has

bowed legs

the hormone calcitonin functions to

decrease the level of calcium ion in the blood

Primary ossification centers develop in long bones in the

diaphysis

The shaft of long bones is called the:

diaphysis

Accelerated closure of the epiphyseal plates could be caused by

elevated levels of estrogen

The lining of the medullary cavity is called the

endosteum

When stress is applied to a bone

the minerals in the bone produce a weak electrical field that attracts osteoblasts.

The interconnecting tiny arches of bone found in spongy bone are called:

trabeculae

A fracture of the bone across its long axis is called a ________ fracture.

transverse

A _____ is a large rough proximal projection on a bone.

trochanter

A ________ is a smooth, grooved bone process shaped like a pulley.

trochlea

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

tuberosity