final on calcium bone osteo. vitamin D Flashcards
5 physiological functions of calcium?
structural component of bones and teeth role in cellular process muscle contraction blood clotting enzymes
4 calcium deficiencys?
rickets
osteomalacia
osteoporosis
tetany (muscle twitch)
4 food sources for calcium?
milk products
oysters
broccoli
legumes
% calcium in the blood?
% calcium in bones and teeth?
1% in blood
99% bones and teeth
where does calcium digestion occure?
in stomach with low pH
where is calcium absorbed?
what does it involve?
in small intestine
active transport and diffusion
what % of digestion calcium is absorbed?
20-30%
what 5 factors enhance calcium absorption?
acidity chime pregnancy deficient lactose vitamin D
4 jobs calcium does in the blood?
neuoromuscluar excitability
blood coagulation
hormonal secretion
enzymatic regulation
1 job calcium does in the bone?
serves as a calcium reservoir or storage
so when calcium is low in the blood it takes it from the bone
how do you get rid of calcium when you have enough?
calcitonin is secreted by the thyroid gland and it targets the bone to suppress resorption and tells the kidney to increase excretion
calcium AI for: teens 19-50 year olds 50+ year olds osteoporosis
teens = 1300 mg 19-50 = 1000 mg 50+ = 1200 mg osteoporosis = 1500 mg
calcium UL?
2500 mg
calcium supplementation, 3 types and % calcium in each one and if you take it with food or not?
try diet first
calcium carbonate 39% take with food
calcium acetate 32%
calcium citrate 30% dont need food
what is the composition of the bone?
the matrix and the cells
the bone matrix is made up of?
compact bone (outside) spongy bone (inside) this is where the minerals are
what is the bone cells made up of?
basic multicellular units (BMU) called: osteoclast osteoblast osteocyte bone lining cells
what are the bone cells called osteoclast used for?
bone resorption
large multinucleated giant cells
degradation of proteins by enzymes and acid
what are bone cells called osteoblast used for?
bone formation
synthesis of matrix proteins
mineralization
what are bone cells called osteocyte?
mature osteoblast embedded in the bone or covering the bone surface after modeling/remodeling
what are the bone lining cells used for?
protective cells covering bone surface
they move so osteoclast can do its job
(like a door)
what are the 2 phases bone modeling and remodeling have?
resorption and formation
what cells do modeling and remodeling use?
osteoclast and osteoblast
what is bone modeling?
reshaping bones during growth
resorption and formation may occur in different spots
what is bone remodeling
maintain bone mass and repairing damage
bone is completely remodeled in 3 years
when bone absorption and resorption is happening, what should be going on?
should have the same amount going into the blood and same amount building the bone
when growing nutrients go into the blood from the bone, this uses?
absorption = adding to different spot
when adding nutrients back to the top of the bone to make it longer this is using?
resorption = taking down to move
what is the most common bone disease?
osteoporosis
osteoporosis fractures are associated with?
high incidence of deep vein thrombosis
pulmonary embolism
mortality rate during the few months after surgery
two sites of fractures?
hip fracture and vertebral fracture
what is kyphosis?
hump back
primary cause of osteoporosis?
bone mineral density
low bone mineral density results from?
failure to achieve optimal peak bone mass during early adulthood
imbalance of bone remodeling, increased bone resorption and decreased bone formation after peak bone mass has been achieved
what is peak bone mass?
maximum bone density genetically determined
osteoporosis happens when a person fails to reach peak bone mass
issues of peak bone mass?
90% of your peak bone mass is achieved by 18 and keeps growing till 30
drops in late 30
faster drop after menopause
risk of osteoporosis depends on peak bone mass loss rate
non modifiable risk factors of osteoporosis?
white or asain family history old female premature menopause long time no period small frame
modifiable risk factors of osteoporosis?
inactivity low intake of calcium and vitamin D poor general health prolonged bed rest smoking excessive drinking high intake of protein or sodium or caffeine or pop (lowers calcium intake)
how to diagnosis osteoporosis?
bone densitometry is the only method
screening for women over 65
best way to tell is by DEXA
what is the mother molecule of vitaminD?
cholesterol
what does vitamin D act as?
hormone &
vitamin
how to activate vitamin D?
cholesterol makes 7-dehydrocholesterol in the skin
then it is activated to cholecalcferol (D3)
then to 25-hydroxycholecaciferol in the liver
then to 1,25-dihydroxycholecalciferol (active D3) in kidney
function of vitamin D?
fracture prevention
how does vitamin D prevent fractures?
it regulates calcium homeostasis and bone mineralzation
how does vitamin D regulate in the GI tract?
it promotes intestinal absorption of calcium by stimulating expression of calbindin (Ca carrier protein)
taking active D3 from kidney to liver making calbindin to raise calcium level in the blood
how does vitamin D regulate in the kidney?
promotes reabsorption of calcium increasing calcium retention
how does vitamin D regulate in bone?
mobilizes calcium from bone and initiates bone remodeling process at the same time it promotes calcium Po4 into osteoporotic bone
vitamin D deficieny in 2 groups of people?
adults
children
adult vitamin D deficiency?
osteomalacia = soft bone
children vitamin D deficiency?
rickets = bow legs
general vitamin D deficiency?
bone pain chronic pain restless sleep muscle weakness unexplained fatigue high BP headache depression all very close to immune disease
AI for vitamin D and the ages?
5 mcg per day ages 1-50
10 mcg per day ages 51-70
15 mcg per day ages 70+
sources of vitamin D?
sun cod liver oil salmon cooked milk butter egg
toxicity of vitamin D?
10x RDA
increased calcium absorption increases calcium deposits on soft tissue making kidney stones
