CH. 6

Bone-forming cells are called A) osteoclasts. B) osteocytes. C) osteons. D) ossification centers. E) osteoblasts.

E

A primary function of the skeletal system is A) maintaining the normal concentrations of calcium and phosphate ions in body fluids. B) absorbing the shock of unexpected rapid body movements. C) facilitating transmission of nerve impulses. D) cushioning abdominal organs such as the kidneys. E) contracting muscles.

A

Channels within bone, involved with cell-to-cell communication, are called A) canaliculi. B) lacunae. C) lamellae. D) perforating canals. E) Haversian canals.

A

In the skeletal system, compact bone is usually located A) where stresses come from a limited range of directions. B) where stresses arrive from many directions. C) only in a narrow ring around the diaphysis of long bones. D) in direct contact with articular cartilages. E) where bones are not heavily stressed.

A

Spongy bone is made up of a network of bony rods or plates called A) trabeculae. B) osteons. C) lamellae. D) canaliculi. E) perforating canals.

A

The following are major steps in the process of endochondral ossification: 1. Bone forms at the diaphysis surface. 2. Secondary ossification centers form in the epiphyses. 3. Chondrocytes enlarge and calcify. 4. Osteoclasts create a marrow cavity. 5. Blood vessels invade the inner cartilage and new osteoblasts form spongy bone at a primary ossification center. The correct order for these events is 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.

A

The presence of ________ strongly indicates that the long bone is still growing. A) an epiphyseal plate B) an articular cartilage C) an epiphyseal line D) an epiphysis E) trabeculae

A

The presence of an epiphyseal line indicates A) epiphyseal growth has ended. B) epiphyseal growth is just beginning. C) growth in bone diameter is just beginning. D) the bone is fractured at that location. E) The presence of an epiphyseal line does not indicate any particular event.

A

Two hormones that work together to elevate calcium levels in the body are ________ and ________. A) parathyroid hormone; calcitriol B) vitamin A; vitamin C C) parathyroid hormone; calcitonin D) growth hormone; calcitonin E) vitamin D3; growth hormone

A

Which cells are very sensitive to calcium levels in the blood? A) muscle cells B) red blood cells C) cartilage cells D) fibroblasts E) epithelial cells

A

A compound fracture A) is caused by an underlying pathology. B) results in bone projecting through the skin. C) is a type of incomplete fracture. D) is also known as a closed fracture. E) is completely internal.

B

Rickets is a condition marked by a softening and bending of bones that occurs in growing children, as a result of ________ deficiency. A) vitamin A B) vitamin D3 C) growth hormone D) vitamin C E) thyroid hormone

B

The bones of the upper arms and thighs are classified as A) short bones. B) long bones. C) flat bones. D) sesamoid bones. E) irregular bones.

B

The medullary cavity of a long bone is lined with A) periosteum. B) endosteum. C) lacunae. D) lamellae. E) osteon.

B

The organic component of the matrix, which makes up around one-third of the mass of bone, is dominated by A) calcium phosphate. B) collagen fibers. C) calcium carbonate. D) calcium carbonate and calcium phosphate. E) dendritic fibers.

B

You and your twin sister, both 18 years of age, were in a car accident. She had a clean break across the humerus and the upper arm bone-no bleeding, no break in the skin. However, you have a very messy break of the distal tibia in the lower leg, requiring pins to be inserted. Which statement is true regarding the differences in your break and your sister's break? A) Your damage is called a fracture, whereas hers is called a break. B) You will be given antibiotics to reduce bacterial infection, whereas your sister will not. C) Your break will not heal whereas her fracture will heal fine. D) Since her fracture did not penetrate through skin, it will not show up on an X-ray, whereas yours will. E) You are given calcium to take but your sister is not.

B

) The connective tissue covering the outer surface of a bone is (the) A) matrix. B) osteon. C) periosteum. D) endosteum. E) articular cartilage.

C

Narrow sheets of calcified matrix are referred to as A) osteons. B) canaliculi. C) lamellae. D) osteoclasts. E) central canals.

C

Osseous tissue is classified as which of the following? A) neural tissue B) nonstriated muscle tissue C) connective tissue D) epithelial tissue E) striated muscle tissue

C

Perforating canals A) are arranged parallel to the long axis of the central canal. B) are always associated with osteons in cancellous bone. C) provide passageways for linking the blood vessels of the central canals with those of the periosteum and the marrow cavity. D) occur in growing juvenile bone, but are obliterated in adult bone. E) are arranged in concentric layers around a central canal.

C

Red bone marrow functions in the formation of A) adipose tissue. B) new bone. C) blood cells. D) osteoblasts. E) osteocytes.

C

Tarsal bones are classified as ________ bones. A) long B) flat C) short D) irregular E) sesamoid

C

The bone cells that contribute to increases in calcium in blood are the A) chondrocytes. B) osteons. C) osteoclasts. D) osteocytes. E) osteoblasts.

C

The hormone calcitonin functions to A) stimulate osteoclast activity. B) stimulate the absorption of calcium and phosphate ions in the digestive tract. C) depress calcium levels in body fluids. D) depress osteoblast activity. E) elevate calcium levels in body fluids.

C

The primary function of ________ is exemplified when bones function as to change the magnitude and direction of the forces generated by skeletal muscle. A) support B) protection C) leverage D) storage E) blood cell production

C

Which of the following accounts for almost two-thirds of the mass of bone tissue? A) cells B) protein fibers C) calcium phosphate D) osteons E) polysaccharides

C

Which of the following occurs in intramembranous ossification? A) Hyaline cartilage model forms. B) Periosteum forms a collar around the cartilage. C) Fibrous connective tissue is converted to bone tissue, which first resembles spongy bone. D) As the bone enlarges, osteoclasts break down some of the spongy bone and create a marrow cavity. E) Ossification centers are formed as blood vessels and osteoblasts enter the centers of the epiphyses.

C

An increase in the diameter of growing bone is termed ________ growth. A) epiphyseal B) endochondral C) intramembranous D) appositional E) ossification

D

During the process of ________, an existing tissue is replaced with bone. A) blood cell production B) calcification C) resorption D) ossification E) osteolysis

D

The shaft of a long bone is called the A) epiphysis. B) trabecula. C) canaliculus. D) diaphysis. E) lamella.

D

Which of the following is found only in compact bone? A) trabeculae B) canaliculi C) osteoblasts D) osteons E) marrow

D

Which of the following primary functions of the skeletal system applies to the role of red bone marrow? A) support B) storage C) protection D) blood cell production E) movement

D

Your doctor suggests that you increase your calcium intake to maintain your healthy bones. You do not understand why the doctor suggested this since you are a healthy 32-year-old. What was the doctor's reasoning? A) The doctor is afraid that you will fall and break a bone. B) The increased calcium intake will then increase your vitamin D blood level. C) Calcium intake will increase the activity of osteoblasts, causing more bone to be formed. D) You are at an age where calcium levels in the bone may start to subside, producing weaker bones later in life. E) As you get older you are more prone to arthritis, and calcium reduces that problem.

D

Osteocytes A) are giant cells with 50 or more nuclei. B) are immature bone cells. C) are the cells responsible for the production of new bone. D) secrete acids and enzymes. E) maintain normal bone structure by recycling the calcium salts in the bony matrix around themselves.

E

The process of depositing calcium salts into a tissue is called A) ossification. B) remodeling. C) resorption. D) osteolysis. E) calcification.

E

Which of the following is an example of the skeletal system's primary function of providing structural support? A) Calcium salts are found in bone. B) Bones change the magnitude and direction of the forces generated by skeletal muscles. C) Red marrow fills the internal cavities of many bones. D) The skull encloses the brain. E) Individual bones provide a framework for the attachment of soft tissues and organs.

E

Which of the following is formed via intramembranous ossification? A) tibia B) humerus C) carpal bones D) femur E) mandible

E

________ are giant bone cells with 50 or more nuclei. A) Osteocytes B) Osteons C) Osteoblasts D) Canaliculi E) Osteoclasts

E