Question 1

Spongy bone

Accepted Answer

Spongy bone contains several layers of lamellae, which are arranged in a trabecular network. Unlike compact bone, spongy bone does not contain osteons or central canals with vessels.

Question 2

Which of the following is true regarding endochondral ossification?

Accepted Answer

Endochondral ossification is a process of bone formation that occurs by replacement of a hyaline cartilage model. The majority of the bones in the body, especially long bones (such as the femur and humerus), are formed by endochondral ossification. Therefore, option A is true. Option B is not true because the epiphysis, which is the end of a long bone, gets its blood supply from the epiphyseal artery, not the diaphyseal periosteal bud. Option C is not entirely accurate as bone begins replacing the cartilage model during fetal development and for several years after birth, not shortly after birth. Option D is also not true because the first bony structure to form during endochondral ossification is the diaphysis (shaft), not the marrow cavity.

Question 3

A large, multinucleate cell with a ruffled border is an

Accepted Answer

A large, multinucleate cell with a ruffled border is most likely an osteoclast, which is responsible for breaking down bone tissue during bone remodeling. Adipocytes are fat cells, osteocytes are mature bone cells, and osteoblasts are responsible for building new bone tissue.

Question 4

The type of bone growth in which bones form directly from mesenchyme is called

Accepted Answer

Intramembranous ossification is the type of bone growth in which bones form directly from mesenchyme, without the intermediate step of cartilage formation.

Question 5

Which bone cell type secretes hydrochloric acid?

Accepted Answer

Osteoclasts are bone cells specialized in breaking down bone tissue, they secrete hydrochloric acid and enzymes that dissolve the mineral components of bone, allowing for the resorption and remodeling of bone tissue.

Question 6

Which statement about growth of long bones is false?

Accepted Answer

The diaphysis actually becomes thicker (not thinner) as the bone lengthens due to the growth of new bone tissue in the periosteum.

Question 7

Which of these is not a step in intramembranous ossification?

Accepted Answer

A bony collar is formed around the diaphysis during endochondral ossification, not intramembranous ossification.

Question 8

Which of these is not a step in endochondral ossification?

Accepted Answer

In endochondral ossification, woven bone does not fill the primary ossification center; instead, cartilage is replaced by bone. Woven bone is more associated with intramembranous ossification.

Question 9

Osteoblasts originate from

Accepted Answer

Osteoblasts originate from mesenchyme cells, which are embryonic cells that give rise to various tissues and organs, including bone.

Question 10

The cartilage of the epiphyseal plates is organized into zones based upon the unique processes occurring in each of these regions. Identify the correct sequence of these processes, from the epiphyseal end toward the diaphysis.

Accepted Answer

The correct sequence of processes in the cartilage of the epiphyseal plates from the epiphyseal end toward the diaphysis is resting, proliferation, hypertrophy, calcification, and ossification. This sequence reflects the progression of cartilage cells as they mature and contribute to bone lengthening.

Question 11

Which of the following is true regarding bone remodeling?

Accepted Answer

Bone remodeling helps in the maintenance of adequate concentrations of calcium and phosphate in our blood. Osteoblasts are bone-forming cells, while osteoclasts are bone-resorbing cells. If osteoblasts are more active than osteoclasts, more bone will be formed than resorbed, which is the opposite of option A. Option B is incorrect as osteoblasts function to form new bone, not break down bone. Option D is incorrect as bone remodeling rates vary depending on the location and type of bone tissue.

Question 12

The process of bone growth is regulated by several hormones throughout the lifetime of an individual. The hormone most influential in skeletal growth prior to adolescence is secreted from the

Accepted Answer

The pituitary gland secretes growth hormone, which regulates bone growth prior to adolescence.

Question 13

The primary center of ossification

Accepted Answer

The primary center of ossification occurs in the diaphysis, which is the shaft of a long bone.

Question 14

The only bone inferior to the skull that develops via intramembranous ossification is the

Accepted Answer

The clavicle is the only bone inferior to the skull that develops via intramembranous ossification. The femur, sternum, and rib all develop via endochondral ossification.

Question 15

Which of the following statements about woven bone is false?

Accepted Answer

Woven bone does contain trabeculae, but they are less organized and less regularly aligned than in mature bone.

Question 16

Which of the following is not present in the central canals of osteons?

Accepted Answer

Osteocytes are not present in the central canals of osteons; they reside in lacunae, which are small cavities between the lamellae of osteons. The central canals, also known as Haversian canals, primarily contain blood vessels and nerves, and are lined by the endosteum.

Question 17

An osteon is composed of

Accepted Answer

An osteon is a basic structural unit of compact bone, consisting of layers of bone lamellae surrounding a central canal. The central canal contains blood vessels and nerves that supply the osteon's cells, while the lamellae provide strength and support to the bone tissue. Choices A and B do not accurately describe the components of an osteon and choice D refers to lamellae found between fully formed osteons.

Question 18

Achondroplasia is a genetic disorder in which cartilage proliferation is inhibited and the epiphyseal plates close early. What would be a consequence of early closure of the epiphysial plates?

Accepted Answer

The early closure of the epiphyseal plates would result in shorter limbs due to decreased bone growth.

Question 19

A hormone that increases the bone-degrading activity of osteoclasts is

Accepted Answer

Parathyroid hormone increases the bone-degrading activity of osteoclasts, leading to an increase in blood calcium levels. This hormone is produced by the parathyroid glands in response to low blood calcium levels.

Question 20

Within a long bone of the skeleton, the circumferential lamellae are located in the

Accepted Answer

Circumferential lamellae are arranged in concentric rings in the external and internal regions of compact bone. They help to strengthen and support the bone. Trabeculae are found in spongy bone, and osteons are the structural units of compact bone that consist of concentric lamellae surrounding a central canal. The marrow cavity is found in the center of long bones and is filled with bone marrow.

Quiz 6: Bones and Skeletal Tissues