Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
18 Cards in this Set
- Front
- Back
|
When signals trigger osteoblasts to lay down bone what other cell do they affect?
|
Osteoclasts are typically inhibited by the same signals
|
|
|
What are the 5 functions of bone?
|
1. Support & shape
2. Protection 3. Allow movement 4. Calcium & phosphate homeostasis 5. Blood cell production |
|
|
What is ground substance composed of?
|
1. extracellular fluid
2. chondroitin sulfate 3. hyaluronan |
|
|
What are the 3 components of the non-cellular portion of bone?
|
1. collagen matrix
2. hydroxyapatite 3. ground substance |
|
|
what provides tensile strength to bones?
|
Collagen
|
|
|
What lays down the collagen for bone?
|
osteoblasts
|
|
|
After collagen is synthesized is polymerizes to form ______.
|
Osteoid (an organic matrix)
|
|
|
What ions/molecules do osteoblasts secrete?
|
calcium Ca++
phosphate HPO42 hydroxyl ions OH- |
|
|
What is the recipe for precipitation of hydroxyapatite?
|
osteoblast -> Collagen -> polymerize -> osteoid -> hydroxyl ion -> high pH of osteoid -> Ca++ & HPO42 supersaturation ->
|
|
|
What is the formula for hydroxyapatite?
|
(Ca10(PO4)6(OH)2)
|
|
|
What is the make-up of collagen?
|
1. Triple helix of 3 alpha (polypeptide) chains
2. proline, lysine, & glycine |
|
|
What is an important consideration of lysine & proline in collagen?
|
they can be hydroxylated
|
|
|
What are the four different general forms of collagen?
|
Gel: stiffen (ECM)
Bundle: strength (tendons) Stacked: cornea (stiff but transmits light) Angled bundle: bone (strength in 3 axes) |
|
|
Where is type I collagen (fibril) found?
|
bone, skin, tendon, cornea, organs
|
|
|
Where is type II collagen (fibril) found?
|
Cartilage,vitreous humor
|
|
|
Where is type III collagen (fibril) found?
|
Skin, vessels, organs
|
|
|
What digests collagen?
|
collagenases
|
|
|
How do you create collagen?
|
1. prepro-alpha-polypeptide is made @ the RER
2. gets cleaved -> pro-alpha chain 3. Pro-alpha chain is HYDROXYLATED in the RER & golgi 4.hydroxylysines are GLYCOSYLATED on the pro-alpha chain 5. procollagen (triple helix) begins to form in the golgi by using DISULFIDE BONDS between 3 pro-alpha chains 6. procollagen is exocytosed into the ECM 7. N-procollagen peptidase & C-procollagen peptidase clip the C&N terminus to form collagen 8. lysyl oxidase forms cross links with other collagen molecules 9. Many collagen fibrils form a collagen fiber |
