Ch. 9 Flashcards
the spongy bone that is found within the ends of long bones is called _____
trabecular
what is false about trabecular bone
it comprises approximately 80% of the skeleton
when does bone growth and modeling start
during fetal development
bone _____ refers to the two-step process in which bone tissue is recycled
remodeling
bone cells that are responsible for bone resorption are called _____
osteoclasts
in addition to proper growth and development, bone remodeling is critical in maintaining _____
blood calcium levels
at what age does bone resorption generally begin to occur more rapidly than bone formation
40
a T-score between +1 and -1 on a DXA signifies _____
normal bone density
Marie is 55 years old and just had her first DXA assessment. The results indicated that she has a T-score of -1.5. What does her T-score indicate?
Compared to a 30 year old healthy adult, she has low bone mass
which of the following techniques can assess the risk of fracture
dual energy x-ray absorptiometry
what is the most abundant mineral in our body
calcium
what is false concerning calcium
99% of calcium is found in the blood and soft tissue
what is not a function of calcium
promotes osteoclasts to break down bone
the average person will absorb no more than _____mg of calcium at one time
500
assuming equal serving sizes, which of the following foods would be the poorest source of calcium
cheddar cheese
the process called bone _____ determines the shape of bones
modeling
what is not a role that calcitonin plays when blood calcium levels are elevated
calcitonin stimulates the action of vitamin d
if a healthy individual were to consume too much calcium from the diet, what is most likely to occur
their gastrointestinal tract would limit the absorption of calcium
what organ is responsible for the synthesis of vitamin d
skin liver and kidneys (all of the above)
where do humans obtain vitamin d
sunight
the primary active form of vitamin d in the human body is _____
calcitriol
what is our primary dietary source of vitamin d
milk
vitamin d toxicity is associated with _____
supplements
calcitonin is a hormone secreted b the _____ gland
thyroid
individuals who have diseases that result in the malabsorption of _____ are at risk for a vitamin d deficiency
fat
insufficient vitamin d during adulthood is associated with _____
osteomalacia
what factor can not inhibit the synthesis of vitamin d
fair skin
vitamin K serves as a _____ to various enzyes involved in the coagulation of blood
coenzyme
newborn infants receive a single injection of vitamin k at birth due to the fact that _____
newborns do not have enough bacteria in their small intestine to make vitamin k
vitamin k’s primary role in the body is _____
blood clotting
in addition to dietary sources, vitamin K is produced in our _____
large intestine
formed in our bones, hydroxyapatite crystals are mineral complexes comprised of calcium and _____
phsphorus
what food is high in phosphorus
meat
when blood calcium levels fall, what does not occur
PTH and vitamin d stimulate osteoblasts to break down bone
most of the body’s phosphorus is stored in _____
the skeleton
what food is a good source of magnesium
green leafy vegetables
how can we increase our absorption of dietary magnesium
eat a high-protein diet
the majority of our body’s flouride is stored in _____
the skeleton
fluorosis is associated with _____
consuming too much fluoride
the individual with the highest risk of developing a viamin d deficiency is an _____
elderly institutionalized adult who consumes no milk and receives little or no sun exposure
the majority of the body’s magnesium is found in the _____
bones
what is a poor source of dietary magnesium
refined grain products
the hormone that assists in maintaining blood calcium levels by stimulating the activation of vitamin d is _____
parathyroid hormone (PTH)
what factor does not contribute to low bone density in the adult years
early onset of menarche in females
phosphorus consumption has increased approximately 10-15% over the past 30 years. this is largely due to the increase consumption of _____
processed foods
