bonezhisto Flashcards Preview

ANNNNNAAtomy > bonezhisto > Flashcards

Flashcards in bonezhisto Deck (22):
1

What do osteoblasts come from? Osteoclasts?

osteoblasts = mesenchymal stem cell
osteoclasts = hematopoietic stem cell

2

What is the one named sesamoid bone in the body?

patella

others located in hands, feet (small bone surrounded by tendon)

3

What does the endosteum line?

All inner parts of the bone: canals, cavites. Only osteoprogenitor layer

4

What does the periosteum line?

The outer part of the bone. Made of a connective tissue layer and a osteoprogenitor layer

5

What produces osteoid?

osteoblasts NOT osteocytes

6

What makes up osteoid?

organic

Type I collagen, bone matrix proteins (BMPs), GAGs

7

What makes up the inorganic part of bone?

hydroxyapatite

8

What does osteocalsin do?

excreted by osteoblasts, promotes calcification

9

What are the two ways osteoblasts help promote calcification?

1. secretion of osteocalsin: brings calcium

2. secretion of alkaline phosphates: PO4- and Ca2+ make up HA

10

What do the cytoplasmic extensions of osteocytes travel through? How do they communicate?

travel through canaliculi, communicate through gap junctions

11

What are major differences between bone and calcified cartilage?

bone:
-type I collagen
-eosinophilic

calcified cartilage:
-type II collagen
-basophilic

12

Another name for primary bone tissue

woven or immature bone

13

Another name for secondary bone tissue

lamellar or mature bone

14

Are spongy bone and compact bone the same histologically?

yes, both are lamellar

15

What is the structural unit of bone?

osteon

central canal contains artery/nerve
surrounded by concentric lamellae circles

16

What is the outer boundary of an osteon?

cement line

17

What are the vessels that run perpendicular to haversian canals, supplying the endosteum and periosteum?

Volkmann's canals

18

What surrounds osteon?

Interstitial lamellae

(remnants of old osteons)

19

How are new osteons made?

1. Osteoclasts dig a canal
2. New blood vessel and osteoprogenitor cells move down into the new canal
3. Osteoblasts start forming new bone from the outside in

20

Does spongy bone contain osteons?

No, but it still has lamellae

21

How are cells in spongy bone supplied?

They are close to the bone marrow, so nutrients don't have to travel far.

22

Where are osteocytes located?

In lacunae in between lamellae