1.
Bone growth in length is called growth, and bone growth in diameter is called growth.
Explanation
Bone growth in length is called interstitial growth, which occurs at the epiphyseal plates located at the ends of long bones. These plates are made up of cartilage cells that divide and mature, causing the bone to lengthen. On the other hand, bone growth in diameter is called appositional growth. This type of growth occurs on the outer surface of the bone, where new bone tissue is added by osteoblasts, while osteoclasts remove old bone tissue from the inner surface. Together, these two types of growth allow bones to increase in both length and diameter.
2.
The crystallized inorganic mineral salts in bone contribute to bone's , while the collagen fibers and other organic molecules provide bone with .
Explanation
The crystallized inorganic mineral salts in bone contribute to bone's hardness, while the collagen fibers and other organic molecules provide bone with tensile strength. This means that the mineral salts give bone its ability to resist compression and withstand forces, making it hard. On the other hand, the collagen fibers and organic molecules give bone its ability to resist stretching and bending, making it strong and able to withstand tension.
3.
Bone resorption involves increased activity of osteoclasts.
Correct Answer
A. True
Explanation
Bone resorption is the process by which osteoclasts break down and remove old or damaged bone tissue. Osteoclasts are specialized cells that are responsible for this activity. They secrete enzymes and acids that dissolve the mineralized matrix of bone, allowing the breakdown and removal of bone tissue. Therefore, increased activity of osteoclasts is indeed involved in bone resorption.
4.
The formation of bone from cartilage is known as endochondral ossification.
Correct Answer
A. True
Explanation
Endochondral ossification is a process in which bone is formed from cartilage. During this process, cartilage gradually transforms into bone through the deposition of minerals and the replacement of cartilage cells with bone cells. This process is responsible for the formation of most bones in the body, including long bones. Therefore, the statement that the formation of bone from cartilage is known as endochondral ossification is true.
5.
The growth of bone is controlled primarily by hormones.
Correct Answer
A. True
Explanation
Bone growth is primarily regulated by hormones. Hormones such as growth hormone and sex hormones play a crucial role in stimulating bone growth and development. Growth hormone, secreted by the pituitary gland, promotes the division and multiplication of bone cells. Sex hormones, such as estrogen and testosterone, are responsible for the growth spurt during puberty and the closure of growth plates. These hormones stimulate the production of bone cells and regulate the balance between bone formation and resorption. Therefore, it is correct to say that the growth of bone is controlled primarily by hormones.
6.
Place in order the steps involved in intramembranous ossification. 1. Bony matrices fuse to form trabeculae 2. Clusters of osteoblasts form a center of ossification that secretes the organic extracellular matrix. 3. Spongy bone is replaced with compact bone on the bone's surface. 4. Periosteum develops on the bone's periphery. 5. The extracellular matrix hardens by deposition of calcium and mineral salts.
Correct Answer
E. 5, 1, 3, 4, 2
7.
Place in order the steps involved in endochondral ossification. 1. Nutrient artery invades the perichondruim 2. Osteoclasts create a marrow cavity 3. Chondrocytes enlarge and calcify 4. Secondary ossification centers appear at epiphyses 5. Osteoblasts become active in the primary ossification center.
Correct Answer
A. 3, 1, 5, 2, 4
8.
Spongy bone differs from compact bone because spongy bone
Correct Answer
E. Is composed of trabeculae that are oriented along lines of stress.
Explanation
Spongy bone differs from compact bone because it is composed of trabeculae that are oriented along lines of stress. Trabeculae are small, needle-like pieces of bone that form a network within spongy bone. This arrangement provides strength and support to the bone, especially in areas where forces are applied. In contrast, compact bone is composed of osteons, which are cylindrical structures that are aligned in the same direction along lines of stress. This arrangement allows compact bone to withstand compressive forces.
9.
A primary effect of weight-bearing exercise on bones is to
Correct Answer
C. Maintain and increase bone mass.
Explanation
Weight-bearing exercise, such as walking or weightlifting, puts stress on the bones, which stimulates the bone cells to become more active. This increased activity leads to the formation of new bone tissue, helping to maintain and increase bone mass. Weight-bearing exercise also helps to strengthen the muscles around the bones, providing additional support and protection. Therefore, the primary effect of weight-bearing exercise on bones is to maintain and increase bone mass.
10.
Place in order the steps involved in the repair of a bone fracture. 1. osteoblast production of trabeculae and bony callus formation 2. formation of a hematoma at the site of fracture 3. resorption of remaining bone fragments and remodeling of bone 4. migration of fibroblasts to the fracture site 5. bridging of broken ends of bones by a fibrocarilaginous callus.
Correct Answer
A. 2, 4, 5, 1, 3
Explanation
The correct order of steps involved in the repair of a bone fracture is as follows:
1. Formation of a hematoma at the site of fracture (2)
2. Migration of fibroblasts to the fracture site (4)
3. Bridging of broken ends of bones by a fibrocarilaginous callus (5)
4. Osteoblast production of trabeculae and bony callus formation (1)
5. Resorption of remaining bone fragments and remodeling of bone (3)