lecture 4 (continuation of height as a biomarker)

Question 1

what are ultradian, infradian, and circadian rhythms?

Answer 1

ultradian: less than 24 hours (appetite)
infradian: more than 24 hours (menstrual cycle)
circadian: 24 hours (height)

Question 1

what is chronobiology?

Answer 1

study of timescales and cycles in biology

Question 2

why does change in height have limitations as a biomarker of osteoporosis?

Answer 2

-must be measured over time
-low sensitivity, doesn’t change that much
-varies during the day
-does not predict the disease state

however, they still monitor it to alert possible osteoporosis

Question 3

what are bones made of

Answer 3

-living cells that build/break down the mineral structure
-serves as function calcium store
-composed of hydroxyapatite, an insoluble deposit of calcium and phosphate

Question 4

how does DEXA measure bone density?

Answer 4

estimates the amount of x-ray absorbing dense material, the hydroxyapatite, that is packed in the extracellular space of the bone

Question 5

how to maximize bone density as a 28 year old?

Answer 5

-consume calcium
-vitamin D
-maintain stable body mass
-get plenty of sleep