Question 1

Osteoclast activity would decrease when ________ levels are elevated.

Accepted Answer

Calcitonin is a hormone produced by the thyroid gland that works to lower blood calcium levels. It does this by inhibiting osteoclast activity, which are the cells responsible for bone resorption. When calcitonin levels are elevated, it means that the activity of osteoclasts is decreased, leading to a reduction in the breakdown of bone and a decrease in the release of calcium into the bloodstream.

Question 2

When a fracture begins to heal, one type of bone cell moves into the fracture site and tears down the damaged bone tissue. Which of the following does this?

Accepted Answer

Osteoclasts are responsible for breaking down bone tissue, which is a crucial step in the process of bone healing. They remove the damaged or old bone tissue, allowing for the formation of new bone tissue by osteoblasts.

Question 3

The remodeling of bone tissue is a function of

Accepted Answer

The remodeling of bone tissue is a continuous process involving the resorption of old or damaged bone by osteoclasts and the formation of new bone tissue by osteoblasts. Osteocytes are mature bone cells that originate from osteoblasts and play a role in maintaining bone tissue, but they are not directly involved in the remodeling process. Chondroblasts and chondrocytes are involved in cartilage formation and maintenance, not bone remodeling. Fibroblasts are involved in the formation of connective tissue, including the collagen matrix of bone, but not directly in bone remodeling.

Question 4

The collar that forms around the opposing ends of bone fragments is called a/an ________.

Accepted Answer

The answer of The collar that forms around the opposing...

Question 5

Osteoclast activity is increased by ________.

Accepted Answer

Parathyroid hormone increases osteoclast activity to release calcium from bones into the bloodstream.

Question 6

Which of the following statements regarding calcium homeostasis is true?

Accepted Answer

When blood calcium levels are too low, the body responds by increasing osteoclast activity. Osteoclasts break down bone, releasing calcium into the bloodstream to elevate the calcium levels back to normal.

Question 7

The radiologist informs Matthew that his fracture has not penetrated the skin, meaning Matthew has a/an ________ fracture.

Accepted Answer

A fracture that has not penetrated the skin is referred to as a "closed" fracture. Open fractures, in contrast, involve a break in the skin.

Question 8

The proper sequence of events in bone repair is

Accepted Answer

The correct sequence for bone repair starts with hematoma formation (blood clotting at the fracture site), followed by callus formation (fibrocartilaginous callus formation), then callus ossification (the callus is replaced by bone), and finally, remodeling of bone (the bone is reshaped to its original form).

Question 9

Which chemical, ingested or synthesized by the body, is necessary for calcium absorption from the intestines?

Accepted Answer

Vitamin D is essential for the absorption of calcium from the intestines. It facilitates the intestinal absorption of calcium, which is crucial for bone health and maintenance of calcium levels in the blood.

Question 10

A bone fracture in which the two bone sections do not separate is a/an ________ fracture.

Accepted Answer

A nondisplaced fracture is where the bone cracks either part or all of the way through, but does not move and maintains its proper alignment. This contrasts with displaced fractures, where the bone fragments shift in position.

Question 11

When blood calcium levels are low

Accepted Answer

When blood calcium levels are low, osteoclast activity increases to break down bone tissue and release calcium into the bloodstream, helping to restore normal calcium levels. Calcitonin, on the other hand, decreases blood calcium levels by inhibiting osteoclast activity, so its secretion would not increase in response to low blood calcium levels.

Question 12

Which structure forms between the ends of a broken bone as well as the marrow cavity?

Accepted Answer

An internal callus forms between the ends of a broken bone as well as within the marrow cavity, providing a bridge of cartilage and bone tissue that helps stabilize the fracture and facilitate healing.

Question 13

An incomplete bone fracture generally found in children is a/an ________.

Accepted Answer

Greenstick fractures are incomplete fractures where the bone bends and cracks, rather than breaking completely into separate pieces. This type of fracture is more common in children because their bones are softer and more flexible.

Question 14

Which of the following is NOT a direct effect of parathyroid hormone (PTH)?

Accepted Answer

Increased calcium uptake by the small intestine is an indirect effect of PTH, mediated through its action on vitamin D activation in the kidneys, which then increases intestinal calcium absorption.

Question 15

Bone remodeling may occur

Accepted Answer

Bone remodeling occurs for various reasons: as bones grow, they adjust to stress (such as from physical activity), during the healing process of fractures, and it is a constant process that occurs throughout a person's lifetime to maintain bone health and structure.

Question 16

In which of the following locations in a growing bone would the greatest osteoclast activity be found?

Accepted Answer

Osteoclast activity is most prominent in the medullary cavity of a growing bone. This is because osteoclasts are responsible for bone resorption, which is crucial for the expansion of the medullary cavity as the bone grows. This process helps in the remodeling of bone and the regulation of calcium and phosphate levels in the body.

Question 17

Sam, an older man, has been diagnosed with osteoporosis, and his blood calcium levels are above normal. The pathologiste found cancer cells that were oversecreting ________ causing Sam's symptoms.

Accepted Answer

Parathyroid hormone (PTH) is responsible for regulating calcium levels in the blood. Cancer cells that oversecrete PTH can lead to hypercalcemia (elevated blood calcium levels) and contribute to the development or worsening of osteoporosis by increasing bone resorption.

Question 18

Miguel fell out of a tree and broke his fall by putting his arm out, fracturing his radius and ulna. The bones were still aligned at the fracture site. Which specific type of bone fracture is Miguel most likely to have?

Accepted Answer

A nondisplaced fracture is where the bone cracks either part or all of the way through, but maintains its proper alignment. This is consistent with Miguel's injury, where his radius and ulna were fractured but remained aligned.

Question 19

Which of the following statements about bone remodeling and repair is correct?

Accepted Answer

Bone remodeling is a process that responds to mechanical stress, where the bone tissue is continuously renewed to maintain bone strength and mineral homeostasis. This process involves the activity of osteoclasts, which break down old bone, and osteoblasts, which form new bone. Increased mechanical stress stimulates this remodeling process to adapt the bone structure for better support, making option D correct.

Question 20

Parathyroid hormone (PTH) causes

Accepted Answer

Parathyroid hormone (PTH) increases RANKL and decreases OPG to stimulate osteoclasts and increase bone resorption, thereby increasing blood calcium levels.

Quiz 6: Skeletal System: Bones and Bone Tissue