Term
What signals are needed to transform a mesenchymal fibroblast into a chondrocyte or an osteoblast? |
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Definition
High BMP
(bone morphogenetic protein) |
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Term
True or false:
chondrocytes are multinucleate |
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Definition
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Term
What signal is needed to transform a myofibroblast into an adipocyte?
a smooth muscle cell? |
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Definition
myofibroblast + low BMP = adipocyte
myofibroblast + no BMP = smooth muscle cell |
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Term
| What are three differences between endochondral bone and intramembranous bone? |
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Definition
Endochondral:
requires collagen template for ossification
mature bone is avascular
long bones & flat bones |
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Term
| What type of collagen links cementum to bone? |
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Definition
| Collagen types 1 and 2 make up PDL fibers |
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Term
Which of the following non-collagenous proteins is the most abundant type in bone?
A. proteoglycans
B. alkaline phosphatase
C. osteonectin
What is the most common type in dentin? |
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Definition
C. osteonectin
~ 2% of bone, function undefined
DSPP - dentin sialophosphoprotein is the most common non-collagenous protein in dentin |
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Term
Which of the body's mineral stores are found in bone in the following amounts?
99%
85%
66% |
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Definition
99% - Ca
85% - PO4
66% - Mg (not consistently found in hydroxyapatite) |
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Term
| What metabolic bone disease is characterized by premature loss of primary teeth? |
|
Definition
Hypophosphatasia
- lack of cementum and PDL fibers
- lack of alkaline phosphatase expression in osteoblasts |
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Term
| Alkaline phosphatase is a hallmark of _____. |
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Definition
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Term
| What effects does PTH have in the kidney? |
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Definition
- inhibits PO4 reabsorption in proximal and distal tubule
- stimulates Calcium reabsorption in distal tuble |
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Term
Which vitamins are water soluble?
Which are fat soluble? |
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Definition
Water soluble: C, B complex
Fat soluble: A, D, E, K |
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Term
Which B vitamin has the highest RDA? |
|
Definition
Niacin
- a precursor for NAD and NADP
- RDA is 19 mg/day
- 3 "d's" of deficiency (pellagra):
dermatitis, diarrhea, dementia (& death if severe) |
|
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Term
| Which anti-tuburculosis drug is a B6 (Pyridoxine) antagonist? |
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Definition
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Term
| Eating a lot of raw eggs can cause a deficiency of which B vitamin? |
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Definition
Biotin
- avidin in raw eggs has high affinity for biotin
- biotin normally produced by intestinal microflora
- acts as coenzyme in carboxylation reactions, covalently bound to enzyme lysyl side chains |
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Term
Which B vitamin is needed to make coenzyme A? |
|
Definition
Pantothenic acid (aka B5)
- hard to have a deficiency, many sources |
|
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Term
What has been the most common vitamin deficiency in the US? |
|
Definition
Folic acid
- precursor for tetrahydrofolate, used as a 1 C unit carrier in oxidation |
|
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Term
| Which 2 enzymes require cofactor forms of B12? |
|
Definition
Homocysteine ---------------> Methionine
Homocysteine Methyltransferase +
N5-Methyl-tetrahydrofolate ----> Tetrahydrofolate
Methyl Malonyl CoA ------------> Succinyl CoA
Methylmalonyl CoA mutase |
|
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Term
Which vitamins are antioxidants?
Of these which is water soluble?
Which has the largest RDA of all the vitamins? |
|
Definition
Antioxidants: C, E, Beta carotene
Vitamin C is water soluble and has the largest RDA = 60 mg/day |
|
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Term
Rickets can be caused by what vitamin deficiency? |
|
Definition
Vitamin D (cholecalciferol) |
|
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Term
What vitamin deficiency can cause hemolysis? |
|
Definition
Vitamin E
- found in vegetables and wheat germ oil
- prevents lipid damage |
|
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Term
Where is vitamin K found in the diet?
What would be a symptom of vitamin K deficiency? |
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Definition
- Made by intestinal bacteria (deficiency rare)
- as vit K is coenzyme for blood clotting factors like prothrombin, deficiency could lead to prolonged blood clotting times |
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Term
How does PTH increase the number of osteoclasts? |
|
Definition
PTH binds to receptors on osteoblasts, and stimulates RANKL differentiation factor
osteoblasts --> preosteoclasts --> osteoclasts |
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Term
What do C cells secrete?
Chief cells? |
|
Definition
C cells of thyroid secrete calcitonin
Chief cells of parathyroid gland secrete PTH
(there is pre-pro form, pro form, and finally PTH) |
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Term
Which organs are involved in Vitamin D synthesis?
What happens in each organ? |
|
Definition
Skin: 7 dehydrocholesterol--> D3 (cholecalciferol)
UV radiation
Liver: D3 ---------> 25(OH)vitamin D3
25 hydroxylase
Kidney: 25(OH)vitamin D3 -----> 1,25(OH)2D3
1,25.. = active form aka calcitriol
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Term
| What causes increased absorption of Ca++ in the intestine? |
|
Definition
Vitamin D
- 1,25(OH)2D3 binds intestinal cytoplasmic receptor --> steroid receptor complex transported to nucleus --> increased synthesis of CALBINDIN --> increased serum Ca++ |
|
|
Term
What is the normal blood Ca++ level?
In what forms is it found in the blood? |
|
Definition
10 mg/100 mL
51% ionized
46% bound to plasma proteins (albumin)
3% complexed to other ions (PO4) |
|
|
Term
| What is the direct effect of PTH on the intestine? |
|
Definition
|
|
Term
|
Definition
aka Osteitis Deformans
- excess osteoclast activity with compensatory osteblast activity
- remodeling disease
- craniofacial lesions and deformities complicate tooth care
- 3% of over 40 population affected |
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Term
What is the effect of calcitonin in bone?
In kidney?
In intestine? |
|
Definition
bone: shrinks osteoclasts
kidney: increases Calcium excretion at supra-physiological levels
intestine: inhibits gastrin |
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Term
| What are the steps for conversion of Beta carotene to retinoic acid? |
|
Definition
b carotene -------> all trans (x2) retinal <-------> dioxygenase
retinol (x2) ------> retinoic acid
retinoic acid used to maintain epithelial cells
retinal used in the visual cycle |
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