Question

name the cylindrical structural unit of compact bone, which consists of a central canal (containing blood vessels, nerves, and lymph vessels) surrounded by concentric rings of calcified matrix.

multiple choice 5 points
bone resorption is the process by which bone is ____ by substances released by ____.

• destroyed; osteoclasts
• deposited; osteoblasts
• destroyed; osteoblasts
• deposited; osteocytes

multiple choice 4 points
parathyroid hormone (pth) is released in response to ______ levels of calcium in the blood.

• low
• high
• perfect

Explanation:

1. The cylindrical structural unit of compact bone is the osteon. It has a central canal with blood - vessels, nerves etc. surrounded by concentric rings of calcified matrix.
2. Bone resorption is the process by which bone is destroyed by substances released by osteoclasts. Osteoclasts break down bone tissue.
3. Parathyroid hormone (PTH) is released in response to low levels of calcium in the blood. PTH acts to increase blood calcium levels.

Answer:

1. Osteon
2. A. destroyed; osteoclasts
3. A. low