Term
|
Definition
| -absorbed by facilitated transport and calcitriol dependent transport in the small intestine |
|
|
Term
| rec calcium intake daily and absorbed in the intestines |
|
Definition
|
|
Term
|
Definition
-expressed on osteoblasts
-binds RANK
-induces differentiation/maturation of osteoclasts |
|
|
Term
|
Definition
| -protein expressed on osteoclast precursor |
|
|
Term
|
Definition
-decoy receptor
-soluble extracellular protein acts like RANK
-prevents bone resorption |
|
|
Term
|
Definition
-physical/chemical signals recruit osteoclasts
-osteoclasts form tight seal and extend villi
-villi secrete acids to breakdown hydoxyapatite
-exposes the protein components
-enzymes like cathepsin K/collagenases break down protein components
-continues for 3 weeks |
|
|
Term
|
Definition
-lactic acid
-carbonic acid
-citric acid
-protons (using carbonic anhydrase and an H+ ATPase pump) |
|
|
Term
|
Definition
-hormones/cytokines stimulate osteoblasts
-osteoblasts proliferate and refill the cavity
-osteoblasts also secrete alkaline phosphatase to promote mineralization
-osteoblasts that get completely surrounded becomes osteocytes |
|
|
Term
|
Definition
| -help control balance of bone formation and resorption via secretion of sclerostin |
|
|
Term
|
Definition
-stimulates osteoclasts
-inc Ca reabsorption
-inc Phos secretion
-inc activation of vit D (inc intestinal Ca absorption)
-negative feedback control |
|
|
Term
|
Definition
-24hr/d
-inc osteoclasts
-inc RANKL
-dec OPG
-net LOSS of bone |
|
|
Term
|
Definition
-3-5hr/day
-inc osteoblast activity
-net GAIN of bone |
|
|
Term
|
Definition
-cholecalciferol
-animal sources
-produced by skin |
|
|
Term
|
Definition
-ergocalciferol
-plant sources |
|
|
Term
|
Definition
-travels to liver when it can be stored or converted to 25 hydroxy vit D by 25 hydoxylase
-then 25 hydroxy travels to kidney where it is activated in PCT by 1a-hydroxylase |
|
|
Term
|
Definition
-increases absorption of dietary Ca in small intestine
-inc expression of intake pump
-inc Ca binding proteins
-in ATP dep Ca pump |
|
|
Term
| other active vit D effects |
|
Definition
-inh PTH synthesis/release
-inc osteoclast
-inc resabsorption of Ca and Phos in DCT
-dec certain cells in immune system |
|
|
Term
|
Definition
-FGF 23
-group of proteins that dec active vit D
-produced by osteocytes |
|
|
Term
|
Definition
-produced by follicular cells of thyroid
-antagonist of PTH
-inhibits osteoclast activity
-stimulates Ca uptake and incorporation into bone matrix
-negative feedback mechanism
-little importance to humans |
|
|
Term
|
Definition
-reduced bone mass and degraded bone architecture due to decreased bone formation, inc bone resorption or both
-spongy bone is remodeled more (spine, pelvis, epiphyses of long bones) |
|
|
Term
|
Definition
-bone mineral density
-measured by dual energy x ray
-measured as g/cm3 |
|
|
Term
|
Definition
| -BMD expressed as standard deviations compared to healthy young adults |
|
|
Term
|
Definition
| -BMD expressed as standard deviations compared to same skeletal region in age matched adults |
|
|
Term
|
Definition
|
|
Term
|
Definition
-thyrotoxicosis
-glucocorticoids
-hyperPTH
-smoking
-alcohol abuse
-intestinal malabsorption or maldigestion
-dietary vit D or Ca def |
|
|
Term
|
Definition
-may be primary or secondary (vit D def, CKD, hypoCa)
-may be due to tumor (bone softens and deforms, depresses nervous system and causes kidney stones) |
|
|
Term
|
Definition
-can be congenital, immune related damage, post surgery or injury
-less Ca released from bones |
|
|
Term
|
Definition
-inadequate diet and or sunlight
-malabsorption
-kidney or liver disorder |
|
|
Term
|
Definition
-bone pain
-fragility
-muscle weakness
-twitching
-lethargy |
|
|
Term
|
Definition
-Rickets (children)
-osteomalacia (adults) (bone softening)
-oesteoporosis |
|
|
Term
|
Definition
-antiresorptive agents
-bone anabolic agents
-Ca
-vit D |
|
|
Term
|
Definition
-HRT
-SERMs
-bisphosphonates
-RANKL antagonists
-calcitonin |
|
|
Term
|
Definition
| -suppress BOTH resorption and formation |
|
|
Term
|
Definition
-tx post menopausal women with osteoporosis
-estrogen dec bone resorption and promotes osteoblast/clasts
-risk of cancer, DVT, stroke
-preferentially combined with progestin component |
|
|
Term
|
Definition
| -aims to have effects of estrogen in bone specifically |
|
|
Term
|
Definition
-most widely used class of OP tx
-analogue of pyrophosphate with POP substituted with PCP |
|
|
Term
|
Definition
-oxygen atoms interact with divalent Ca and concentrate with Ca in bone
-when osteoclast resorbe, it is released
-BP is internalized by osteoclasts where it causes apoptosis |
|
|
Term
| common characteristics of BPs |
|
Definition
-poor intestinal absorption
-take on empty stomach with only water for 30-60 min
-IV formulations can rarely cause acute renal failure/hepatitis
-not metabolized byt can accumulate in bone
-may slow bone healing (osteonecrosis of jaw) |
|
|
Term
| other possible used of BPs |
|
Definition
-nonmalignant hyperCa
-bone marrow malignancies
-hypogonadism
-hyperthyroidism
-para/tetra/hemipalegia
-Guillan Barre syndrome |
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