1.8b Bone Cells

Question 1

What are the four main types of bone cells?

Answer 1

Osteoblasts, osteocytes, osteoclasts, and bone lining cells.

Question 2

Where are osteoblasts typically located?

Answer 2

On the outer surface of trabecular bone, lining developing bone tissue.

Question 3

What is the main function of osteoblasts?

Answer 3

To secrete the extracellular matrix of bone — both the unmineralized osteoid and mineralized hydroxyapatite.

Question 4

Are osteoblasts mature or immature cells?

Answer 4

They are immature bone cells that build bone tissue.

Question 5

What happens to osteoblasts after they complete their function?

Answer 5

They can undergo apoptosis, become bone lining cells, or mature into osteocytes.

Question 6

What is the role of bone lining cells?

Answer 6

They protect bone surfaces and contribute to maintaining bone tissue homeostasis.

Question 7

What do osteocytes develop from?

Answer 7

They develop from osteoblasts that become embedded within the bone matrix.

Question 8

What is the function of osteocytes?

Answer 8

They maintain the existing bone matrix and sense mechanical load on the bone.

Question 9

How do osteocytes respond to mechanical stress on bone?

Answer 9

They activate signaling pathways to stimulate osteoblasts to form new bone and osteoclasts to resorb old bone.

Question 10

What type of stimulus do osteocytes detect to help maintain bone structure?

Answer 10

Mechanical load or stress, such as from exercise or weight-bearing activity.

Question 11

Which hormones do osteocytes respond to?

Answer 11

Hormones that regulate bone and calcium metabolism, such as parathyroid hormone (PTH).

Question 12

How do osteocytes mediate hormonal responses in bone?

Answer 12

They relay hormone signals to osteoblasts and osteoclasts to adjust bone formation or resorption.

Question 13

What is the primary function of osteoclasts?

Answer 13

To resorb or break down existing bone matrix.

Question 14

How do osteoclasts resorb bone?

Answer 14

They dissolve bone matrix, absorb it into their own cells, then release the digested material into the bloodstream.

Question 15

What triggers osteoclast activity?

Answer 15

Increased levels of parathyroid hormone (PTH).

Question 16

What happens when osteoclasts break down hydroxyapatite?

Answer 16

Calcium and other minerals are released from bone into the bloodstream.

Question 17

Why is bone resorption by osteoclasts beneficial?

Answer 17

It creates space for osteoblasts to build new bone and releases calcium needed for other body functions like muscle contraction.

Question 18

How do osteoblasts and osteoclasts functionally differ?

Answer 18

Osteoblasts build bone matrix, while osteoclasts break down bone matrix.

Question 19

What is the relationship between osteocytes, osteoblasts, and osteoclasts?

Answer 19

Osteocytes coordinate bone remodeling by signaling osteoblasts to form new bone and osteoclasts to resorb old bone.

Question 20

What happens when parathyroid hormone levels increase?

Answer 20

Osteoclasts are activated to break down bone and release calcium into the bloodstream.