Term
| What biochemical processes does calcium play a role in? |
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Definition
NCHEF
Neuromuscular excitation
Coagulation of blood
Hormone secretion
Enzyme activity
Fertilization |
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Term
| Calcium is stored as _____ in bones |
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Definition
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Term
| In regards to cells, is most calcium intra or extra cellular |
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Definition
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Term
| Describe the different states/forms of extracellular Ca2+ |
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Definition
50% free ionized Ca
40% bound to protein
10% in a complex with phosphate & citrate |
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Term
True or False
Calcium is not well regulated in the body |
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Definition
False
very tightly regulated! |
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Term
| What parts of the cell is Ca2+ associated with? |
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Definition
plasma mmb
ER mmb
mitochondrial mmb |
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Term
| What is the recommended daily Ca intake? |
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Definition
|
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Term
| What percentage of Ca is absorbed in the SI? |
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Definition
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Term
| Total body calcium = _____ minus _____ |
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Definition
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Term
| What hormones regulate the movement of calcium between the bone, kidney & intestine? Which are most important in adults? |
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Definition
PTH
Calcitriol
Calcitonin
PTH & Calcitriol |
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Term
True or False
The parathyroid gland can be safely removed |
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Definition
| false - it is essential for life! |
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Term
| What are the two cells types in parathyroid glands? |
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Definition
Chief cells (produce PTH)
oxyphils (unknown function) |
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Term
| Does PTH raise or lower plasma [Ca2+]? |
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Definition
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Term
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Definition
| it is not, it is secreted continuously |
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Term
| What happens to PTH secretion in the case of hypercalcaemia? |
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Definition
| PTH secretion will decrease |
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Term
| How does PTH raise blood Ca2+ concentrations? (3) |
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Definition
-stimulates osteoclasts to resorb bone
-stimulates kidneys to resorb Ca2+
-stimlates kidneys to produce enzyme to activate Vit D, which promotes Ca2+ absorption across the intestinal epithelium |
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Term
| What enzyme produced by the kidneys is important in increase Ca2+ absorption? How? |
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Definition
1-alpha-hydroxylase
promotes conversion of 25-hydroxvitamin D3 to 1,25-dihydroxyvitamin D3 which promotes absorption of Ca2+ across the intestinal epithelium |
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Term
| What is the precursor for Vit D3? |
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Definition
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Term
| What type of Vit D is found in supplements? Fish? |
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Definition
supplements - D2
Fish - D3 |
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Term
| Describe the process of producing active Vit D3 from sunlight |
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Definition
1. 7-dehydrocholesterol + UVB produces Vit D3
2. Vit D3 secreted into bloodstream as prehormone
3. In liver, converted to 25-hydroxy Vit D3
4. 1-alphahydroxylase converts to 1,25-dihydroxy Vit D3 in kidneys |
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Term
| Can dogs & cats produce D3 from sunlight? |
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Definition
| no, it is essential in their diet |
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Term
| What effects does D3 have on Ca2+? |
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Definition
stimulates intestinal absorption
stimulates osteoclast activity (resorption) |
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Term
| When Ca2+ plasma levels are high, what does the thyroid do? |
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Definition
|
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Term
true or false
Calcitonin is essential for regulating Ca2+ in adults |
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Definition
false
patients who have had their thyroid removed do not experience hypercalcaemia |
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Term
|
Definition
-targets kidneys to excrete more calcium & phosphate
-inhibits resorption of bone |
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Term
| What is more tightly regulated, phosphate levels or calcium levels? |
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Definition
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Term
| A patient shows hypercalcaemia, frequent bone fractures, and mineralization of soft tissue. What is the issue? |
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Definition
| hyperparathyroidism (too much PTH being secreted) |
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Term
| A patient exhibits hypocalcaemia, muscle weakness, cardiac arrhythmia. What is the issue? |
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Definition
| hypoparathyroidism (too little PTH) |
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Term
| Lack of Vit D will cause what disease in children? What are the clinical signs? |
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Definition
Ricketts
-stunted growth, bone deformities |
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Term
| Lack of Vit D will cause what disease in adults? What are the clinical signs? |
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Definition
osteomalacia
bone pain, fractures |
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Term
| What is the most common bone disorder? |
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Definition
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Term
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Definition
| demineralization of bone (resorption) |
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Term
| What are the risk factors for osteoporosis? |
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Definition
-females (especially post-menopausal)
-lack of exercise
-diet deficient in calcium |
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Term
| Why is osteoporosis a significant concern? |
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Definition
-it is highly prevalent, 1 in 3 women and 1 in 3 men will suffer a fracture related to it
-huge financial cost nationwide
-reduced quality of life
-hip fractures are common, can result in death or disability |
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Term
| At what age does osteoporosis typically begin? |
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Definition
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Term
| What is the best treatment for osteoporosis? |
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Definition
| prevention! exercise, get lots of Vit D & calcium |
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Term
| What hormone therapies can be used to treat osteoporosis? |
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Definition
| administer calcitonin to antagonize effects of PTH |
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