DEXA Anatomy & Physiology of Bone Structure 5

Question 1

The metaphysis of a long bone is best described as the region:

Accepted Answer

Flared zone between the epiphysis and diaphysis containing the former growth plate

Answer

The metaphysis is the wider transitional region between the epiphysis and the diaphysis, encompassing the area of the former growth plate in skeletally mature individuals.

Question 2

Mechanotransduction in bone refers to:

Accepted Answer

The process by which mechanical loads are converted to cellular biochemical signals that regulate bone remodeling

Answer

Mechanotransduction describes how osteocytes sense mechanical strain and translate it into biochemical signals (e.g., nitric oxide, prostaglandins) that regulate bone formation and resorption.

Question 3

Vitamin D's principal role in bone physiology is to:

Accepted Answer

Enhance intestinal absorption of calcium and phosphate to support mineralization

Answer

Active vitamin D (1,25-dihydroxyvitamin D) promotes intestinal absorption of calcium and phosphate, providing the mineral substrate needed for bone mineralization.

Question 4

The lacunocanalicular system in bone primarily serves to:

Accepted Answer

Allow osteocytes to communicate and receive nutrients via fluid-filled channels

Answer

The lacunocanalicular network consists of lacunae (osteocyte cell bodies) connected by canaliculi (tiny channels) through which nutrients, waste, and signaling molecules diffuse.

Question 5

Degenerative changes such as osteophytes and aortic calcification can artificially _______ lumbar spine BMD measurements on DEXA.

Accepted Answer

Increase

Answer

Osteophytes, vertebral fractures, and overlying aortic calcifications increase X-ray attenuation in the scan field, falsely elevating apparent lumbar BMD values.

(DEXA) DEXA Bone Density Scan Certification Practice Test

(DEXA) DEXA Bone Density Scan Certification Practice Test

DEXA Anatomy & Physiology of Bone Structure 5